EXICURE, INC. (Form: 424B5, Received: 08/01/2019 06:07:13)

Filed Pursuant to Rule 424(b)(5)

Registration No. 333-230175

PROSPECTUS SUPPLEMENT

(To Prospectus dated July 24, 2019)

27,500,000 Shares

Common Stock

We are offering 27,500,000 shares of our common stock.

We are an “emerging growth company” under applicable Securities and Exchange Commission rules and are subject to reduced public company reporting requirements.

Our common stock was previously quoted on the OTC Market Group’s OTCQB ^® Market quotation system under the ticker symbol “XCUR.” On July 30, 2019, the last reported sale price of our common stock was $1.85 per share. In connection with this offering, our common stock has been approved for listing on the Nasdaq Capital Market under the symbol “XCUR” and is expected to begin trading on July 31, 2019.

Investing in our securities involves significant risks. Please read the information contained in or incorporated by reference under the heading “Risk Factors” beginning on page S-7 of this prospectus supplement, and under similar headings in other documents filed after the date hereof and incorporated by reference into this prospectus supplement and the accompanying prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.



	PER SHARE		TOTAL
Public offering price	$	2.00	$	55,000,000
Underwriting discounts and commissions(1)	$	0.12	$	3,300,000
Proceeds, before expenses, to us	$	1.88	$	51,700,000

(1) We have agreed to reimburse the underwriters for certain expenses. We refer you to “Underwriting” beginning on page S-21 of this prospectus supplement for additional information regarding total underwriting compensation.

Certain of our existing stockholders, who are affiliated with certain of our directors, have agreed to purchase an aggregate of approximately $2.6 million in shares of common stock in this offering at the public offering price. The underwriters will receive the same underwriting discount on any shares purchased by these stockholders as they will on any other shares sold to the public in this offering.

We have granted the underwriters an option for a period of 30 days from the date of this prospectus supplement to purchase an additional 4,125,000 shares of our common stock. If the underwriters exercise the option in full, the total underwriting discounts and commissions payable by us will be $3,795,000, and the total proceeds to us, before expenses, will be $59,455,000.

Delivery of the shares of common stock is expected to be made on or about August 2, 2019.

Sole Book-Running Manager

Guggenheim Securities

Lead Manager

Chardan



	Co-Managers
H.C. Wainwright & Co.		Ladenburg Thalmann

The date of this prospectus supplement is July 30, 2019.

TABLE OF CONTENTS

Prospectus Supplement



	Page
ABOUT THIS PROSPECTUS SUPPLEMENT	S-ii
PROSPECTUS SUPPLEMENT SUMMARY	S-1
THE OFFERING	S-6
RISK FACTORS	S-7
NOTE REGARDING FORWARD-LOOKING STATEMENTS	S-10
USE OF PROCEEDS	S-12
CAPITALIZATION	S-13
DILUTION	S-15
MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO NON-U.S. HOLDERS	S-17
UNDERWRITING	S-21
LEGAL MATTERS	S-26
EXPERTS	S-26
WHERE YOU CAN FIND MORE INFORMATION	S-26
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	S-27

Prospectus



	Page
ABOUT THIS PROSPECTUS	1
WHERE YOU CAN FIND MORE INFORMATION	1
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	2
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	4
ABOUT THE COMPANY	6
RISK FACTORS	10
USE OF PROCEEDS	11
DIVIDEND POLICY	12
GENERAL DESCRIPTION OF SECURITIES WE MAY OFFER	13
DESCRIPTION OF CAPITAL STOCK	14
DESCRIPTION OF DEBT SECURITIES	19
DESCRIPTION OF DEPOSITARY SHARES	26
DESCRIPTION OF WARRANTS, OTHER RIGHTS AND UNITS	27
PLAN OF DISTRIBUTION	29
LEGAL MATTERS	32
EXPERTS	33

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus are part of a shelf registration statement on Form S-3 (File No. 333-230175), as amended, that we filed with the Securities and Exchange Commission, or SEC, on July 11, 2019 and was declared effective by the SEC on July 24, 2019, pursuant to which we may from time to time offer various securities in one or more offerings.

This document is in two parts. The first part is this prospectus supplement, which describes the terms of this offering and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference herein or therein. The second part, the accompanying prospectus, including the documents incorporated by reference into the accompanying prospectus, provides more general information. Generally, when we refer to this prospectus, we are referring to both parts of this document combined. To the extent there is a conflict between the information contained in this prospectus supplement and the information contained in the accompanying prospectus or any document incorporated by reference herein or therein filed prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement; provided that if any statement in one of these documents is inconsistent with a statement in another document having a later date - for example, a document incorporated by reference in the accompanying prospectus - the statement in the document having the later date modifies or supersedes the earlier statement.

Neither we nor the underwriters have authorized anyone to provide information different from that contained in this prospectus supplement and the accompanying prospectus that we have authorized for use in this offering. If anyone provides you with different or inconsistent information, you should not rely on it. Neither we nor the underwriters take any responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. Neither the delivery of this prospectus supplement and the accompanying prospectus, nor the sale of our common stock means that information contained in this prospectus supplement and the accompanying prospectus, is correct after their respective dates. It is important for you to read and consider all information contained in this prospectus supplement and the accompanying prospectus, including the information incorporated by reference into this prospectus supplement and the accompanying prospectus in making your investment decision.

This prospectus supplement does not contain all of the information that is important to you. You should also read and consider the information in the documents to which we have referred you in the sections entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” in this prospectus supplement. You should rely only on the information contained or incorporated by reference in this document. You should assume that the information in this prospectus supplement and the accompanying prospectus, as well as the information we have filed with the SEC and incorporated by reference in this document, is accurate only as of its date or the date which is specified in those documents.

We are offering to sell, and seeking offers to buy, and the underwriters are soliciting offers to buy, these securities only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe any restrictions relating to, the offering of the securities and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

This prospectus supplement and the information incorporated herein by reference include trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included or incorporated by reference herein are the property of their respective owners.

Unless the context otherwise requires, in this prospectus supplement the “Company,” “we,” “us,” “our” and similar names refer to Exicure, Inc. and its subsidiaries.

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PROSPECTUS SUPPLEMENT SUMMARY

This summary highlights certain information about us, this offering and selected information contained elsewhere in or incorporated by reference into this prospectus supplement and the accompanying prospectus. This summary is not complete and does not contain all of the information that you should consider before deciding whether to invest in our common stock. For a more complete understanding of Exicure and this offering, we encourage you to read and consider carefully the more detailed information in this prospectus supplement and the accompanying prospectus, including the information incorporated by reference in this prospectus supplement and the accompanying prospectus, including the information referred to under the heading “Risk Factors” in this prospectus supplement beginning on page S-7.

Overview

We are a clinical-stage biotechnology company developing therapeutics for immuno-oncology, inflammatory diseases and genetic disorders based on our proprietary Spherical Nucleic Acid, or SNA, technology. SNAs are nanoscale constructs consisting of densely packed synthetic nucleic acid sequences that are radially arranged in three dimensions. We believe the design of our SNAs gives rise to distinct chemical and biological properties that may provide advantages over other nucleic acid therapeutics and enable therapeutic activity outside of the liver. We have advanced our SNA therapeutic candidates through three Phase 1 clinical trials. These candidates include AST-008 addressing immuno-oncology, and XCUR17 and AST-005 addressing psoriasis. We have also shown in preclinical studies that SNAs may have therapeutic potential in neurology, ophthalmology, pulmonology, and gastroenterology.

Clinical development programs

Immuno-oncology

AST-008 is an SNA consisting of toll-like receptor 9, or TLR9, agonists designed for immuno-oncology applications. TLR9 agonists bind to and activate TLR9 receptors. We believe AST-008 may be used for immuno-oncology applications as a monotherapy or in combination with checkpoint inhibitors. Checkpoint inhibitors are therapeutics that prevent tumors from evading destruction by the immune system. We have observed that the administration of AST-008 as a monotherapy can have anti-tumor activity in mouse models of colon cancer, breast cancer, lymphoma and melanoma. We have also observed that, in preclinical studies in a variety of tumor models, AST-008, applied in combination with certain checkpoint inhibitors, exhibited anti-tumor responses and survival rates that were greater than those demonstrated by checkpoint inhibitors alone. We have also demonstrated that AST-008 was active when administered subcutaneously, intratumorally or intravenously, in both prevention and established mouse tumor models. The administration of AST-008 also produced localized as well as abscopal anti-tumor activity in mouse cancer models. Additionally, the administration of AST-008 in combination with certain checkpoint inhibitors conferred adaptive immunity in breast and colon cancer mouse models.

During the fourth quarter of 2018 the U.S. Food and Drug Administration, or the FDA, opened the investigational new drug application, or IND, for AST-008 and informed us that our proposed Phase 1b/2 trial may proceed. During the first half of 2019, we opened five clinical trial sites and began recruiting and dosing patients in that trial. The Phase 1b/2 is an open-label, multi-center trial designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy of intratumoral AST-008 injections alone and in combination with intravenous pembrolizumab in patients with advanced solid tumors. We plan to recruit patients with advanced or metastatic Merkel cell carcinoma, head and neck squamous cell carcinoma, cutaneous squamous cell carcinoma, and melanoma. The primary outcome measure is the safety and tolerability of AST-008 alone and in combination with pembrolizumab. Secondary outcomes include the recommended Phase 2 dose and disease assessment with RECIST 1.1. As of July 28, 2019, we have dosed nine patients in the first three cohorts of the Phase 1b stage of the clinical trial. We have observed no treatment related serious adverse events, or SAEs, nor have we observed any dose-limiting toxicity, or DLT, among the treated subjects. We are now proceeding to the fourth dosing cohort in the clinical trial. We intend to disclose results from the Phase 1b stage of the clinical trial in late 2019 and initiate the Phase 2 stage of the trial in 2020.

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Inflammatory diseases

XCUR17

XCUR17 is an SNA that targets the mRNA that encodes interleukin 17 receptor alpha, or IL-17RA, a protein that is considered essential in the initiation and maintenance of psoriasis. Although the availability of inhibitors of TNF revolutionized the systemic treatment of severe psoriasis, studies of disease pathogenesis have shifted attention to the IL-17 pathway in which IL-17RA is a key driver of psoriasis. Our strategy is to reduce the levels of IL-17RA in the skin by topically applying XCUR17. In preclinical studies, XCUR17 inhibited IL-17RA in the keratinocytes of the skin.

We filed a clinical trial authorization, or CTA, for a Phase 1 clinical trial of XCUR17 in patients with psoriasis in Germany in the third quarter of 2017, and we began dosing patients in April 2018. The Phase 1 clinical trial, which had final patient visits in the fourth quarter of 2018, was a randomized, double-blinded, placebo-controlled trial in 21 patients with mild to moderate chronic plaque psoriasis designed to assess the safety of XCUR17 formulated as a topical gel, and to evaluate early signs of efficacy. All patients received three strengths of XCUR17 gel, a vehicle gel, and a positive comparator (Daivonex® cream), which were all applied on different areas of psoriatic skin within each individual patient.

In the fourth quarter of 2018, we reported results from the Phase 1 trial of XCUR17. In the case of XCUR17, of the 21 treated patients, 11 treated with the highest strength XCUR17 gel were observed to have a reduction in redness and improvement in healing as determined by blinded physician assessments. Further, the highest strength XCUR17 gel showed a statistically significant improvement in psoriasis symptoms versus the vehicle gel. By comparison, 17 of the 21 patients treated with the positive comparator showed a clinical response, while four patients treated with the placebo vehicle had a clinical response.

There were no adverse safety events related to treatment with XCUR17 observed. In addition to the safety, tolerability and clinical assessments, the trial measured psoriatic infiltrate thickness over the 26-day treatment period. No relevant changes in mean psoriatic infiltrate thickness were observed for the three XCUR17 gels or the active ingredient-free vehicle gel. At this time, assessments of IL-17RA mRNA levels from skin biopsies collected from the treated areas in patients have not yet been correlated with the clinical or infiltrate thickness assessments.

Dermelix License Agreement

On February 17, 2019, we entered into a License and Development Agreement, or the Dermelix License Agreement, with DERMELIX, LLC, d/b/a Dermelix Biotherapeutics. Under the terms of agreement, Dermelix licensed worldwide rights to research, develop, and commercialize Exicure’s technology for the treatment of Netherton Syndrome, or NS, and, at Dermelix’s option, up to five additional rare skin indications.

Dermelix will initially develop a targeted therapy for the treatment of NS. NS is a rare and severe autosomal recessive disorder caused by loss-of-function mutations in the SPINK5 gene, which encodes the serine protease inhibitor LEKTI involved in skin barrier function. NS affects approximately one in 200,000 children born each year, and is characterized by severely inflamed, red, scaled, itchy skin, and patients are at increased risk of mortality in the first year of life due to recurrent infections and dehydration as a result of the impaired skin barrier. Currently, there are no approved treatments for NS patients and off-label use of standard of care treatments are of limited utility. In partnership with Dermelix, we will seek to open an IND for a proposed SNA therapeutic for NS in 2020.

Under the terms of the Dermelix License Agreement, Exicure received an upfront payment of $1 million at closing of the transaction and will receive an additional $1 million upon the exercise of each of the five options granted to Dermelix. Exicure will be responsible for conducting the early-stage development for each indication up to IND enabling toxicology studies. Dermelix will undertake subsequent development, commercial activities and financial responsibility. For each of NS as well as any additional licensed product for which Dermelix exercises one of its options, Exicure is eligible to receive potential payments totaling up to $13.5 million upon achievement of certain development and regulatory milestones and up to $152.5 million upon achievement of certain sales

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milestones per indication in each of six indications. In addition, Exicure will receive low double-digit royalties on annual net sales for SNA therapeutics developed.

Other Inflammatory Diseases

We believe that one of the key strengths of our proprietary SNAs is that they have the potential to enter a number of different cells and organs. As a consequence, we are also conducting early stage research activities in ophthalmology, pulmonology, and gastroenterology.

We believe promising therapeutic targets for SNAs include antibody targets with confirmed therapeutic benefit. We envision inhibiting these targets with local application of SNAs in a variety of therapeutic areas. We believe that this approach combines the benefits of specifically inhibiting validated targets without the potential safety issues associated with systemic therapy.

Genetic disorders

We are investigating the utility of our SNA technology for the treatment of neurological conditions and have ongoing research programs underway. In the fall of 2018, we completed a biodistribution study in rats comparing nusinersen to nusinersen in SNA format. Nusinersen, marketed by Biogen Inc., is a linear nucleic acid therapeutic approved by the FDA in late 2016 for the treatment of spinal muscular atrophy, or SMA. We found that more nusinersen in SNA format was retained in the rats’ brain and spinal cord compared to nusinersen retained in the rats’ brain and spinal cord at 24, 72 and 168 hours.

On June 26, 2019, we announced data from a preclinical study evaluating the biodistribution of SNAs in the non-human primate central nervous system. In our study, 7mg of radio-labeled SNAs were injected intrathecally into cynomolgus monkeys. The biodistribution of the SNAs was followed for 14 days by PET/CT scans. SNAs were observed throughout the entire brain and were found both in the brain stem as well as inside the brain. High content of SNA was observed in all 46 regions of the brain examined. These key data indicate that the SNA platform may be well-suited for development of new therapeutics directed towards diseases of the central nervous system.

We are now formulating our strategy for developing a pipeline of SNA therapeutics targeting neurological diseases. Preclinical research is underway in a number of indications including, spinal muscular atrophy, Huntington’s disease, spinocerebellar ataxia type 3 (SCA3), SCA2, SCA1, Friedreich’s ataxia, and Batten disease. We believe this preclinical research may lead to a therapeutic candidate for one of the above neurological indications.

AST-005

AST-005 is an SNA targeting TNF for the treatment of mild to moderate psoriasis. AST-005 is intended to be administered locally in a gel to psoriatic lesions. In a completed Phase 1 clinical trial, AST-005, when topically administered to the skin of patients with mild to moderate psoriasis, resulted in no drug associated adverse events, and demonstrated a reduction of TNF mRNA. The TNF mRNA reduction elicited by the highest strength of AST-005 gel was statistically significant when compared to the effects of the vehicle.

On December 2, 2016, we entered into a research collaboration, option and license agreement with Purdue Pharma L.P., referred to as the Purdue Collaboration. As part of our collaboration with Purdue, a Phase 1b clinical trial was conducted in Germany to evaluate the effect of AST-005 gel in patients with chronic plaque psoriasis. The trial demonstrated that AST-005 is safe and tolerable in patients at higher doses than were previously studied, however, the study did not result in a statistically significant decrease in echo lucent band thickness, one of the key indicators of efficacy in patients with psoriasis. In April 2018, Purdue notified us that it had declined to exercise its option to develop AST-005 at that time, but that it also intended to retain rights relating to the TNF target, and Purdue reserved its right to continue joint development, with Exicure, of new anti-TNF drug candidates and to retain its exclusivity and other rights to AST-005.

S-3

In April 2019, Purdue notified us that it will not be selecting any collaboration targets pursuant to the Purdue Collaboration. As a result, we will not receive any research, regulatory and commercial sales milestones contingent upon successful development of such collaboration targets. Purdue re-asserted its right to develop new anti-TNF therapeutic candidates. At this time, there are no active development activities underway for a new anti-TNF therapeutic candidate. As a consequence, we also believe that it is highly unlikely that we will receive any research, regulatory and commercial sales milestones for any anti-TNF therapeutic candidates.

Our Clinical Development Programs

Our clinical development programs include the development of one SNA therapeutic candidate to address unmet medical needs in the treatment of solid tumors and one SNA therapeutic candidate to address unmet medical needs in the treatment of mild to moderate psoriasis. We are also conducting early stage research activities in neurology, ophthalmology, respiratory and gastrointestinal applications.

The table below sets forth the stage of development of our SNA therapeutic candidates as of July 28, 2019:

TLR9 = Toll-like Receptor 9; IL17RA = Interleukin 17 Receptor Alpha

Recent Developments

Board of Director Appointments

On July 21, 2019, our Board of Directors, or the Board, upon the recommendation of the Nominating and Corporate Governance Committee, appointed each of Timothy P. Walbert and Jeffrey L. Cleland to the Board, effective immediately. Each of Mr. Walbert and Dr. Cleland will serve as a Class II director, to hold office until the date of the annual meeting of stockholders following the year ending December 31, 2021 or until his earlier death, resignation or removal.

Immediately following completion of the offering, we expect to appoint an individual designated by Abingworth LLP, an expected investor in the offering, to serve as a member of the Board and a Class I Director, and we expect to appoint an additional director recommended by another expected investor in the offering.

Financial Update

While we have not finalized our full financial results for the fiscal quarter ended June 30, 2019, we expect to report that we had approximately $17.2 million of cash as of June 30, 2019. This amount is preliminary, has not been audited and is subject to change pending completion of our unaudited financial statements for the three and six months ended June 30, 2019. Additional information and disclosures would be required for a more complete understanding of our financial position and results of operations as of June 30, 2019. We expect to complete our unaudited financial statements for the quarter ended June 30, 2019 subsequent to the completion of this offering. It is possible that we or our independent registered public accounting firm may identify items that require us to make adjustments to the preliminary estimated cash balance set forth above and those changes could be material.

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Accordingly, undue reliance should not be placed on this preliminary estimate. The preliminary estimate is not necessarily indicative of any future period and should be read together with the sections titled “Risk Factors” and “Note Regarding Forward-Looking Statements” in this prospectus supplement, and our financial statements, related notes and other financial information incorporated by reference herein.

Our Corporate Information

We were originally incorporated in the State of Delaware on February 6, 2017 under the name “Max-1 Acquisition Corporation.” Prior to the Merger (as defined below), Max-1 was a “shell” company registered under the Securities Exchange Act of 1934, as amended, or the Exchange Act, with no specific business plan or purpose until it began operating the business of Exicure Operating Company, or Exicure OpCo, through a transaction on September 26, 2017, or the Merger. Exicure OpCo was originally formed as a limited liability company under the name AuraSense Therapeutics, LLC in the State of Delaware in June 2011 and was a clinical-stage biotechnology company developing gene regulatory and immuno-oncology therapeutics based on its proprietary SNA technology. AuraSense Therapeutics, LLC was subsequently converted into AuraSense Therapeutics, Inc., a Delaware corporation, on July 9, 2015, and changed its name on the same date to Exicure, Inc. Immediately after giving effect to the Merger and the initial closing of the 2017 Private Placement, the business of Exicure OpCo became our business.

Our corporate headquarters are located at 8045 Lamon Avenue, Suite 410, Skokie, IL 60077, and our telephone number is (847) 673-1700. We maintain a website at www.exicuretx.com, to which we regularly post copies of our press releases as well as additional information about us. Our filings with the SEC will be available free of charge through the website as soon as reasonably practicable after being electronically filed with or furnished to the SEC. Information contained in our website is not a part of, nor incorporated by reference into, this prospectus or our other filings with the SEC, and should not be relied upon.

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THE OFFERING



Common stock offered by us	27,500,000 shares

Underwriters’ option to purchase additional shares	We have granted the underwriters an option for a period of up to 30 days from the date of this prospectus supplement to purchase up to an additional 4,125,000 shares of our common stock at the public offering price less the underwriting discounts and commissions.

Common stock to be outstanding after this offering	71,858,000 shares (75,983,000 shares assuming the underwriters exercise in full their option to purchase 4,125,000 additional shares).

Use of proceeds	We intend to use the net proceeds from this offering (i) to advance AST-008 through a Phase 1b/2 clinical trial; (ii) to develop an SNA therapeutic candidate for a neurology condition and advance it into Phase 1 clinical trials; and (iii) for general corporate purposes. See “Use of Proceeds.”

Risk factors	An investment in our common stock involves a high degree of risk. See “Risk Factors” beginning on page S-7 of this prospectus supplement, and under similar headings in other documents filed after the date hereof and incorporated by reference into this prospectus supplement and the accompanying prospectus.

Nasdaq Symbol	In connection with this offering, our common stock has been approved for listing on the Nasdaq Capital Market under the symbol “XCUR” and is expected to begin trading on July 31, 2019.

Outstanding Shares

The number of shares of our common stock to be outstanding after this offering is based on 44,358,000 shares of our common stock outstanding as of March 31, 2019, and excludes:


•	5,125,659 shares of our common stock issuable upon the exercise of stock options outstanding as of March 31, 2019 at a weighted-average exercise price of $2.26 per share;


•	11,790 shares of our common stock issued upon stock option exercises subsequent to March 31, 2019 through July 29, 2019;


•	431,750 shares of our common stock reserved under the Exicure, Inc. 2017 Employee Stock Purchase Plan (the “ESPP”);


•	694,372 shares of our common stock reserved for issuance under the Exicure, Inc. 2017 Equity Incentive Plan (the “2017 Plan”); and


•	413,320 shares of our common stock issuable upon the exercise of outstanding warrants as of March 31, 2019, at a weighted average exercise price of $3.00 per share.

Except as otherwise indicated herein, all information in this prospectus supplement, including the number of shares that will be outstanding after this offering, does not assume or give effect to the exercise of the underwriters’ option to purchase additional shares in this offering.

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RISK FACTORS

Investing in our common stock involves a high degree of risk. Before investing in our common stock, you should carefully consider the risks described below, together with all of the other information contained in this prospectus supplement and the accompanying prospectus and incorporated by reference herein and therein, including from our Annual Report on Form 10-K for the year ended December 31, 2018, as well as any amendment or update to our risk factors reflected in subsequent filings with the SEC. Some of these factors relate principally to our business and the industry in which we operate. Other factors relate principally to your investment in our securities. The risks and uncertainties described therein and below are not the only risks facing us. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also materially and adversely affect our business and operations.

If any of the matters included in the following risks were to occur, our business, financial condition, results of operations, cash flows or prospects could be materially and adversely affected. In such case, you may lose all or part of your investment.

Risks Related to this Offering

You will experience immediate and substantial dilution in the net tangible book value per share of the common stock you purchase in this offering.

The offering price per share of our common stock being offered is substantially higher than the net tangible book value per share of our outstanding common stock. As a result, investors purchasing shares of our common stock in this offering will incur immediate dilution of $1.07 per share, after giving effect to the sale of an aggregate of 27,500,000 shares of our common stock at an offering price of $2.00 per share, and after deducting underwriting fees and estimated offering expenses payable by us. As a result of the dilution to investors purchasing shares in this offering, investors may receive significantly less than the purchase price paid in this offering, if anything, in the event of our liquidation. See “Dilution” on page S-15 of this prospectus supplement for a more detailed discussion of the dilution you will incur if you purchase shares of our common stock in this offering.

In addition, as of March 31, 2019, we had outstanding options to acquire 5,125,659 shares of our common stock and outstanding warrants to acquire 413,320 shares of our common stock. The issuance of shares of our common stock upon exercise of the stock options or warrants could result in dilution to the interests of other holders of our common stock and could adversely affect our stock price.

Substantial future sales or other issuances of our common stock could depress the market for our common stock.

Sales of a substantial number of shares of our common stock, or the perception by the market that those sales could occur, could cause the market price of our common stock to decline or could make it more difficult for us to raise funds through the sale of equity in the future.

In connection with this offering, we and our directors, executive officer, and certain of our significant stockholders have entered into lock-up agreements for a period of 90 days following this offering (which period may be extended under certain circumstances). We and our directors, executive officers, and certain of our significant stockholders may be released from such lock-up agreements prior to the expiration of the lock-up period at the sole discretion of Guggenheim Securities (See “Underwriting” beginning on page S-21 of this prospectus supplement). Upon expiration or earlier release of the lock-up, we and our directors, executive officers and certain of our significant stockholders may sell shares into the market, which could adversely affect the market price of shares of our common stock.

Future issuances of our common stock or our other equity securities could further depress the market for our common stock. We expect to continue costs associated with our research and development programs, such as the cost of research and development, preclinical studies, clinical trials, and the regulatory approval process for

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therapeutic candidates, and general and administrative costs associated with our operations, and to satisfy our funding requirements, we may need to sell additional equity securities. The sale or the proposed sale of substantial amounts of our common stock or our other equity securities may adversely affect the market price of our common stock and our stock price may decline substantially. Our stockholders may experience substantial dilution and a reduction in the price that they are able to obtain upon sale of their shares. New equity securities issued may have greater rights, preferences or privileges than our existing common stock.

We have broad discretion in the use of the net proceeds of this offering and, despite our efforts, we may use the net proceeds in a manner that does not increase the value of your investment.

Our management will have broad discretion in the application of our existing cash and the net proceeds from this offering, including for any of the purposes described in the section titled "Use of Proceeds," and you will not have the opportunity as part of your investment decision to assess whether such proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of our existing cash and the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. Our management might not apply our existing cash and the net proceeds from this offering in ways that ultimately increase the value of your investment. The failure by our management to apply these funds effectively could harm our business. Pending their use, we may invest the net proceeds from this offering in short-term, investment-grade, interest-bearing securities. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

We may not be able to meet the continued listing requirements for the Nasdaq Capital Market or another nationally recognized stock exchange, which could limit investors’ ability to make transactions in our securities and subject us to additional trading restrictions.

In connection with this offering, our common stock has been approved for listing on the Nasdaq Capital Market under the symbol “XCUR” and is expected to begin trading on July 31, 2019.

Further, in order to remain listed on the Nasdaq Capital Market, we will be required to meet the continued listing requirements of the Nasdaq Capital Market or any other U.S. or nationally recognized stock exchange to which we may apply and be approved for listing. We may be unable to satisfy these continued listing requirements, and there is no guarantee that our common stock will remain listed on the Nasdaq Capital Market or any other U.S. or nationally recognized stock exchange. If, after listing, our common stock is delisted from the Nasdaq Capital Market or any other U.S. or nationally recognized stock exchange, we could face significant material adverse consequences, including:


•	a limited availability of market quotations for our common stock;


•	reduced liquidity with respect to the market for our common stock;


•	a determination that our common stock is a “penny stock,” which will require brokers trading in our common stock to adhere to different rules, possibly resulting in a reduced level of trading activity in the secondary trading market for our common stock;


•	a limited amount of news and analyst coverage; and


•	decreased ability to issue additional shares of our common stock or obtain additional financing in the future.

An active trading market for our common stock may never develop following this offering.

Prior to this offering, trading in our common stock on the OTC Market Group’s OTCQB ^® Market quotation system has been limited and sporadic. An active trading market for our common stock may never develop or be sustained, which may affect your ability to sell your common stock and could depress the market price of your common stock. In connection with this offering, our common stock has been approved for listing on the Nasdaq

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Capital Market under the symbol “XCUR” and is expected to begin trading on July 31, 2019. Listing on the Nasdaq Capital Market may not ensure that an actual market will develop for our common stock. As a result, no assurances can be given that you will be able to readily sell your common stock at a price equal to or above the price you paid.

We do not currently intend to pay dividends on our common stock, and any return to investors is expected to come, if at all, only from potential increases in the price of our common stock.

We have never declared or paid cash dividends on our capital stock, and you should not rely on an investment in our common stock to provide dividend income. We currently intend to retain all of our future earnings, if any, to finance the growth and development of our business and do not anticipate declaring or paying any cash dividends for the foreseeable future. In addition, our term loan facility contains certain covenants that limit our ability to pay or make any dividend and the terms of any future debt agreements may further preclude us from paying dividends. As a result, capital appreciation, if any, of our common stock will be your sole source of gain for the foreseeable future.

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NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, together with the accompanying prospectus includes and incorporates by reference “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and releases issued by the SEC and within the meaning of Section 27A of the Securities Act, and Section 21E of the Exchange Act. All statements other than statements of historical fact are “forward-looking statements” for purposes of this prospectus supplement and the accompanying prospectus. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “will,” “would,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “intend,” “predict,” “seek,” “contemplate,” “project,” “continue,” “potential,” “ongoing,” “goal,” or the negative of these terms or other comparable terminology. These forward-looking statements include, but are not limited to, statements about:


•	the initiation, timing, progress and results of our research and development programs, preclinical studies, clinical trials and IND application, Investigational Medicinal Product Dossier, CTA, New Drug Application, or NDA, or other regulatory submissions;


•	our receipt and timing of any milestone payments or royalties under any current or future research collaboration and license agreements or arrangements;


•	our ability to identify and develop therapeutic candidates for treatment of additional disease indications;


•	our or a current or future collaborator’s ability to obtain and maintain regulatory approval of any of our therapeutic candidates;


•	the rate and degree of market acceptance of any approved therapeutic candidates;


•	the commercialization of any approved therapeutic candidates;


•	our ability to establish and maintain collaborations and retain commercial rights for our therapeutic candidates in the collaborations;


•	the implementation of our business model and strategic plans for our business, technologies and therapeutic candidates;


•	our estimates of our expenses, ongoing losses, future revenue and capital requirements, including our expectations relating to our need for additional financing;


•	our ability to obtain additional funds for our operations;


•	our ability to obtain and maintain intellectual property protection for our technologies and therapeutic candidates and our ability to operate our business without infringing the intellectual property rights of others;


•	our reliance on third parties to conduct our preclinical studies and clinical trials;


•	the ability of our third party supply and manufacturing partners to supply the materials and components for, and manufacture, our research and development, preclinical and clinical trial supplies;


•	our ability to attract and retain qualified key management and technical personnel;


•	our expectations regarding the time during which we will be an emerging growth company under the Jumpstart Our Business Startups Act of 2012;


•	our financial performance;


•	our use of proceeds from this offering;


•	In Part II., Item 9A. Controls and Procedures of our Annual Report on Form 10-K for the year ended December 31, 2018, which is incorporated by reference in this prospectus supplement, the statements regarding our internal controls; and


•	the impact of government regulation and developments relating to our competitors or our industry.

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These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. In evaluating such forward-looking statements, you should specifically consider various factors that may cause actual results to differ materially from current expectations, including the risks and uncertainties outlined under the heading “Risk Factors” contained in this prospectus supplement and the accompanying prospectus, and in any other documents incorporated herein or therein (including in our most recent annual report on Form 10-K, subsequent quarterly reports on Form 10-Q and other filings we make with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act).

Any forward-looking statement in this prospectus supplement and the accompanying prospectus reflects our current view with respect to future events and is subject to these and other risks, uncertainties and assumptions relating to our business, results of operations, industry and future growth. Given these uncertainties, you should not place undue reliance on these forward-looking statements. No forward-looking statement is a guarantee of future performance. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This prospectus supplement also contains estimates, projections and other information concerning our industry, our business and the markets for certain therapeutics, including data regarding the estimated size of those markets, their projected growth rates and the incidence of certain medical conditions. Information that is based on estimates, forecasts, projections or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained these industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources. In some cases, we do not expressly refer to the sources from which these data are derived.

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USE OF PROCEEDS

We estimate that the net proceeds from our issuance and sale of shares of our common stock in this offering will be approximately $51.1 million, or approximately $58.9 million if the underwriters exercise their option to purchase additional shares in full, after deducting the underwriting discounts and commissions and the estimated offering expenses payable by us.

We currently intend to use the net proceeds from this offering to (i) to advance AST-008 through a Phase 1b/2 clinical trial; (ii) to develop an SNA therapeutic candidate for a neurology condition and advance it into Phase 1 clinical trials; and (iii) for general corporate purposes.

The amounts and timing of our use of the net proceeds from this offering will depend on a number of factors, such as the timing and progress of our commercialization efforts, research and development efforts, the timing and progress of any partnering efforts, technological advances and the competitive environment for our products. As of the date of this prospectus supplement, we cannot specify with certainty all of the particular uses for the net proceeds to us from the sale of the shares of our common stock offered by us hereunder. Accordingly, our management will have broad discretion in the timing and application of these proceeds. Pending application of the net proceeds as described above, we intend to temporarily invest the proceeds in short-term, interest-bearing instruments.

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CAPITALIZATION

The following table sets forth our cash and our capitalization as of March 31, 2019:


•	on an actual basis; and


•	on an as adjusted basis to reflect the sale by us of 27,500,000 shares of our common stock in this offering at the public offering price of $2.00 per share, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

You should read the data set forth in the table below in conjunction with our financial statements, including the related notes, and "Management's Discussion and Analysis of Financial Condition and Results of Operations" from our Quarterly Report on Form 10-Q for the quarter ended March 31, 2019, which is incorporated by reference into this prospec tus supplement.



	As of March 31, 2019
	Actual			As Adjusted
	(unaudited)
	(in thousands, except share data)
Cash and cash equivalents	$	22,196		$	73,896

Total liabilities	$	9,029		$	9,673

Stockholders' equity:
Preferred stock, $0.0001 par value; 10,000,000 shares authorized, no shares issued and outstanding, actual and as adjusted	$	—		$	—
Common stock, $0.0001 par value; 200,000,000 shares authorized, 44,358,000 shares issued and outstanding, actual; 71,858,000 shares issued and outstanding, as adjusted	4			7
Additional paid-in capital	76,431			127,484
Accumulated deficit	(60,280		)	(60,280		)
Total stockholders' equity	$	16,155		$	67,211
Total capitalization	$	16,155		$	67,211

The number of shares of our common stock to be outstanding after this offering is based on 44,358,000 shares of our common stock outstanding as of March 31, 2019, and excludes:


•	5,125,659 shares of our common stock issuable upon the exercise of stock options outstanding as of March 31, 2019 at a weighted-average exercise price of $2.26 per share;


•	11,790 shares of our common stock issued upon stock option exercises subsequent to March 31, 2019 through July 29, 2019;


•	431,750 shares of our common stock reserved under the ESPP;


•	694,372 shares of our common stock reserved for issuance under the 2017 Plan; and


•	413,320 shares of our common stock issuable upon the exercise of outstanding warrants as of March 31, 2019, at a weighted average exercise price of $3.00 per share.

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DILUTION

Purchasers of our common stock in this offering will experience immediate dilution to the extent of the difference between the public offering price per share of our common stock, and the as adjusted net tangible book value per share of our common stock immediately after this offering.

Our net tangible book value as of March 31, 2019 was approximately $15.6 million, or $0.35 per share of our common stock. Net tangible book value per share of our common stock is determined by dividing total tangible assets less total liabilities, excluding items such as intangibles, by the aggregate number of shares of our common stock outstanding as of March 31, 2019. Dilution per share to new investors represents the difference between the amount per share paid by purchasers for our common stock in this offering and the as adjusted net tangible book value per share of our common stock immediately following the completion of this offering.

After giving effect to the sale of 27,500,000 shares of our common stock in this offering at the public offering price of $2.00 per share, and after deducting the underwriting discounts and commissions and the estimated offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2019 would have been approximately $66.7 million, or approximately $0.93 per share of our common stock. This represents an immediate increase in net tangible book value of $0.58 per share of our common stock to our existing stockholders and an immediate dilution in net tangible book value of $1.07 per share of our common stock to purchasers in this offering.

The following table illustrates this calculation on a per share basis:



Offering price per share in this offering			$	2.00
Net tangible book value per share as of March 31, 2019	$	0.35
Increase in net tangible book value per share attributable to purchasers in this offering	$	0.58
As adjusted net tangible book value per share immediately after this offering			$	0.93
Dilution per share to purchasers in this offering			$	1.07

If the underwriters exercise their option in full to purchase additional shares of our common stock in this offering at the public offering price of $2.00 per share, the as adjusted net tangible book value per share after the offering would be $0.98 per share, the increase in the net tangible book value per share to existing stockholders would be $0.63 per share and the dilution to new investors purchasing securities in this offering would be $1.02 per share.

The above table is based on 44,358,000 shares of our common stock outstanding as of March 31, 2019. Unless specifically stated otherwise, the information in this prospectus supplement is as of March 31, 2019 and excludes:


•	5,125,659 shares of our common stock issuable upon the exercise of stock options outstanding as of March 31, 2019 at a weighted-average exercise price of $2.26 per share;


•	11,790 shares of our common stock issued upon stock option exercises subsequent to March 31, 2019 through July 29, 2019;


•	431,750 shares of our common stock reserved under the ESPP;


•	694,372 shares of our common stock reserved for issuance under the 2017 Plan; and


•	413,320 shares of our common stock issuable upon the exercise of outstanding warrants as of March 31, 2019, at a weighted average exercise price of $3.00 per share.

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To the extent that options or warrants are exercised, other equity awards vest, new equity awards are issued under the 2017 Plan or pursuant to inducement awards, or we issue additional shares of common stock in the future, there may be further dilution to investors participating in this offering. In addition, we may choose to raise additional capital because of market conditions or strategic considerations, even if we believe that we have sufficient funds for our current or future operating plans. If we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

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MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following discussion is a summary of certain material U.S. federal income tax considerations for non-U.S. holders (as defined below) with respect to their ownership and disposition of shares of our common stock issued pursuant to this offering. For purposes of this discussion, a non-U.S. holder means a beneficial owner of our common stock that is for U.S. federal income tax purposes:


•	a non-resident alien individual;


•	a foreign corporation or any other foreign organization taxable as a corporation for U.S. federal income tax purposes; or


•	a foreign estate or trust, the income of which is not subject to U.S. federal income tax on a net income basis.

This discussion does not address the tax treatment of partnerships or other entities that are pass-through entities for U.S. federal income tax purposes or persons that hold their common stock through partnerships or other pass-through entities. A partner in a partnership or other pass-through entity that will hold our common stock should consult his, her or its tax advisor regarding the tax consequences of acquiring, holding and disposing of our common stock through a partnership or other pass-through entity, as applicable.

This discussion is based on current provisions of the U.S. Internal Revenue Code of 1986, as amended, which we refer to as the Code, existing and proposed U.S. Treasury Regulations promulgated thereunder, current administrative rulings and judicial decisions, all as in effect as of the date of this prospectus and all of which are subject to change or to differing interpretation, possibly with retroactive effect. Any such change or differing interpretation could alter the tax consequences to non-U.S. holders described in this prospectus. There can be no assurance that the Internal Revenue Service, which we refer to as the IRS, will not challenge one or more of the tax consequences described herein. We assume in this discussion that a non-U.S. holder holds shares of our common stock as a capital asset within the meaning of Section 1221 of the Code, generally property held for investment.

This discussion does not address all aspects of U.S. federal income taxation that may be relevant to a particular non-U.S. holder in light of that non-U.S. holder’s individual circumstances nor does it address U.S. state, local or non-U.S. taxes, the alternative minimum tax, the rules regarding qualified small business stock within the meaning of Section 1202 of the Code, the Medicare tax on net investment income or any other aspect of any U.S. federal tax other than the income tax. This discussion also does not consider any specific facts or circumstances that may apply to a non-U.S. holder and does not address the special tax rules applicable to particular non-U.S. holders, such as:


•	insurance companies;


•	tax-exempt or governmental organizations;


•	financial institutions;


•	brokers or dealers in securities;


•	regulated investment companies;


•	pension plans;


•	“controlled foreign corporations,” “passive foreign investment companies,” and corporations that accumulate earnings to avoid U.S. federal income tax;


•	“qualified foreign pension funds” as defined in Section 897(I)(2) of the Code and entities all of the interests of which are held by qualified foreign pension funds;


•	persons that have a functional currency other than the U.S. dollar;


•	persons deemed to sell our common stock under the constructive sale provisions of the Code;


•	persons that hold our common stock as part of a straddle, hedge, conversion transaction, synthetic security

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or other integrated investment;


•	persons who hold or receive our common stock pursuant to the exercise of any employee stock option or otherwise as compensation; and


•	certain U.S. expatriates.

This discussion is for general information only and is not tax advice. Accordingly, all prospective non-U.S. holders of our common stock should consult their tax advisors with respect to the U.S. federal, state, local and non-U.S. tax consequences of the ownership and disposition of our common stock.

Distributions on Our Common Stock

As described in the “Risk Factors” section above, we do not anticipate paying any cash dividends on our capital stock in the foreseeable future. Distributions, if any, on our common stock will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. If a distribution exceeds our current and accumulated earnings and profits, the excess will be treated as a tax-free return of the non-U.S. holder’s investment, up to such holder’s tax basis in the common stock. Any remaining excess will be treated as capital gain, subject to the tax treatment described below in “Gain on Sale or Other Taxable Disposition of Our Common Stock.” Any such distributions will also be subject to the discussions below under the sections titled “Backup Withholding and Information Reporting” and “FATCA.”

Subject to the discussion in the following two paragraphs in this section, dividends paid to a non-U.S. holder generally will be subject to withholding of U.S. federal income tax at a 30% rate or such lower rate as may be specified by an applicable income tax treaty between the United States and such holder’s country of residence.

Dividends that are treated as effectively connected with a trade or business conducted by a non-U.S. holder within the United States and, if an applicable income tax treaty so provides, that are attributable to a permanent establishment or a fixed base maintained by the non-U.S. holder within the United States, are generally exempt from the 30% withholding tax if the non-U.S. holder satisfies applicable certification and disclosure requirements. However, such U.S. effectively connected income, net of specified deductions and credits, is taxed at the same graduated U.S. federal income tax rates applicable to United States persons (as defined in the Code). Any U.S. effectively connected income received by a non-U.S. holder that is a corporation may also, under certain circumstances, be subject to an additional “branch profits tax” at a 30% rate or such lower rate as may be specified by an applicable income tax treaty between the United States and such holder’s country of residence.

A non-U.S. holder of our common stock who claims the benefit of an applicable income tax treaty between the United States and such holder’s country of residence generally will be required to provide a properly executed IRS Form W-8BEN or W-8BEN-E (or successor form) to the applicable withholding agent and satisfy applicable certification and other requirements. Non-U.S. holders are urged to consult their tax advisors regarding their entitlement to benefits under a relevant income tax treaty. A non-U.S. holder that is eligible for a reduced rate of U.S. withholding tax under an income tax treaty may obtain a refund or credit of any excess amounts withheld by timely filing a U.S. tax return with the IRS.

Gain on Sale or Other Taxable Disposition of Our Common Stock

Subject to the discussions below under “Backup Withholding and Information Reporting” and “FATCA,” a non-U.S. holder generally will not be subject to any U.S. federal income or withholding tax on any gain realized upon such holder’s sale or other taxable disposition of shares of our common stock unless:

•

the gain is effectively connected with the non-U.S. holder’s conduct of a U.S. trade or business and, if an applicable income tax treaty so provides, is attributable to a permanent establishment or a fixed base maintained by such non-U.S. holder in the United States, in which case the non-U.S. holder generally will be taxed on a net income basis at the graduated U.S. federal income tax rates applicable to United States persons (as defined in the Code) and, if the non-U.S. holder is a foreign corporation, the branch profits tax

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described above in “Distributions on Our Common Stock” also may apply;

•

the non-U.S. holder is a nonresident alien individual who is present in the United States for 183 days or more in the taxable year of the disposition and certain other conditions are met, in which case the non-U.S. holder will be subject to a 30% tax (or such lower rate as may be specified by an applicable income tax treaty between the United States and such holder’s country of residence) on the net gain derived from the disposition, which may be offset by certain U.S. source capital losses of the non-U.S. holder, if any (even though the individual is not considered a resident of the United States), provided that the non-U.S. holder has timely filed U.S. federal income tax returns with respect to such losses; or

•

we are, or have been, at any time during the five-year period preceding such sale or other taxable disposition (or the non-U.S. holder’s holding period, if shorter) a U.S. real property holding corporation, unless our common stock is regularly traded on an established securities market and the non-U.S. holder holds no more than 5% of our outstanding common stock, directly or indirectly, actually or constructively, during the shorter of the 5-year period ending on the date of the disposition or the period that the non-U.S. holder held our common stock. Generally, a corporation is a U.S. real property holding corporation only if the fair market value of its U.S. real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests plus its other assets used or held for use in a trade or business. Although there can be no assurance, we do not believe that we are, or have been, a U.S. real property holding corporation, or that we are likely to become one in the future. No assurance can be provided that our common stock will be regularly traded on an established securities market for purposes of the rules described above.

Backup Withholding and Information Reporting

We must report annually to the IRS and to each non-U.S. holder the gross amount of the distributions on our common stock paid to such holder and the tax withheld, if any, with respect to such distributions. Non-U.S. holders may have to comply with specific certification procedures to establish that the holder is not a United States person (as defined in the Code) in order to avoid backup withholding at the applicable rate with respect to dividends on our common stock. Dividends paid to non-U.S. holders subject to withholding of U.S. federal income tax, as described above in “Distributions on Our Common Stock,” generally will be exempt from U.S. backup withholding.

Information reporting and backup withholding will generally apply to the proceeds of a disposition of our common stock by a non-U.S. holder effected by or through the U.S. office of any broker, U.S. or foreign, unless the holder certifies its status as a non-U.S. holder and satisfies certain other requirements, or otherwise establishes an exemption. Generally, information reporting and backup withholding will not apply to a payment of disposition proceeds to a non-U.S. holder where the transaction is effected outside the United States through a non-U.S. office of a broker. However, for information reporting purposes, dispositions effected through a non-U.S. office of a broker with substantial U.S. ownership or operations generally will be treated in a manner similar to dispositions effected through a U.S. office of a broker.

Non-U.S. holders should consult their tax advisors regarding the application of the information reporting and backup withholding rules to them. Copies of information returns may be made available to the tax authorities of the country in which the non-U.S. holder resides or is incorporated under the provisions of a specific treaty or agreement. Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules from a payment to a non-U.S. holder can be refunded or credited against the non-U.S. holder’s U.S. federal income tax liability, if any, provided that an appropriate claim is filed with the IRS in a timely manner.

FATCA

Provisions of the Code commonly referred to as the Foreign Account Tax Compliance Act, or FATCA, generally impose a U.S. federal withholding tax at a rate of 30% on payments of dividends on our common stock paid to a foreign entity unless (i) if the foreign entity is a “foreign financial institution,” such foreign entity undertakes certain due diligence, reporting, withholding, and certification obligations, (ii) if the foreign entity is not a “foreign financial institution,” such foreign entity identifies certain of its U.S. investors, if any, or (iii) the foreign entity is otherwise

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exempt under FATCA. Such withholding may also apply to gross proceeds from the sale or other disposition of our common stock, although under recently proposed U.S. Treasury Regulations, no withholding would apply to such gross proceeds. The preamble to the proposed regulations specifies that taxpayers (including withholding agents) are permitted to rely on the proposed regulations pending finalization. Under certain circumstances, a non-U.S. holder may be eligible for refunds or credits of this withholding tax. An intergovernmental agreement between the United States and an applicable foreign country may modify the requirements described in this paragraph. Non-U.S. holders should consult their tax advisors regarding the possible implications of this legislation on their investment in our common stock and the entities through which they hold our common stock, including, without limitation, the process and deadlines for meeting the applicable requirements to prevent the imposition of the 30% withholding tax under FATCA.

The preceding discussion of U.S. federal income tax considerations is for general information only. It is not tax advice. Each prospective investor should consult its own tax advisor regarding the particular U.S. federal, state and local and non-U.S. tax consequences of purchasing, holding and disposing of our common stock, including the consequences of any proposed change in applicable laws.

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UNDERWRITING

Guggenheim Securities, LLC is acting as representative of each of the underwriters named below. Subject to the terms and conditions set forth in the underwriting agreement between us and the underwriters, each of the underwriters has agreed, severally and not jointly, to purchase from us, the number of shares of common stock set forth opposite its name below.



Underwriter		Number of Shares
Guggenheim Securities, LLC		22,000,000
Chardan Capital Markets, LLC		2,750,000
H.C. Wainwright & Co., LLC		1,375,000
Ladenburg Thalmann & Co. Inc.		1,375,000
Total		27,500,000

Subject to the terms and conditions set forth in the underwriting agreement, the underwriters have agreed, severally and not jointly, to purchase all of the shares sold under the underwriting agreement if any of these shares are purchased. If an underwriter defaults, the underwriting agreement provides that the purchase commitments of the non-defaulting underwriters may be increased or the underwriting agreement may be terminated.

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute to payments the underwriters may be required to make in respect of those liabilities.

The underwriters are offering the shares subject to their acceptance of the shares of common stock from us and subject to prior sale. The underwriters reserve the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

Commissions and Discounts; Expenses

The underwriters have advised us that they propose initially to offer the shares to the public at the public offering price set forth on the cover of this prospectus supplement and to dealers at that price less a concession not in excess of $0.072 per share. After the initial offering, the public offering price, concession or any other term of the offering may be changed.

The following table shows the public offering price, underwriting discounts and commissions and proceeds before expenses to us. The information assumes either no exercise or full exercise by the underwriters of their option to purchase additional shares of our common stock from us, as applicable.



			Total
	Per Share		No Exercise	Full Exercise
Public offering price	$	2.00	55,000,000	63,250,000
Underwriting discounts and commissions to be paid by us	$	0.12	3,300,000	3,795,000
Proceeds, before expenses, to us	$	1.88	51,700,000	59,455,000

We estimate expenses payable by us in connection with this offering, other than the underwriting discounts and

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commissions referred to above, will be approximately $600,000, which includes certain expenses incurred by the underwriters in connection with this offering that will be reimbursed by us. We have agreed to reimburse the underwriters for certain expenses incurred by them in connection with this offering (including certain fees and expenses of counsel for the underwriters in an amount not to exceed $225,000, and fees and expenses related to filings with and review by FINRA).

Option to Purchase Additional Shares

We have granted the underwriters an option to purchase up to an additional 4,125,000 shares of common stock at the public offering price, less the underwriting discounts and commissions, within 30 days from the date of this prospectus supplement. If the underwriters exercise this option, each underwriter will be obligated, subject to conditions contained in the underwriting agreement, to purchase a number of additional shares proportionate to that underwriter’s initial amount reflected in the above table.

No Sales of Similar Securities

In connection with this offering, we have agreed with the underwriters that, subject to certain customary exceptions, without the prior written consent of Guggenheim Securities, LLC on behalf of the underwriters, we will not, for a period ending 90 days after the date of this prospectus supplement, or the Lock-Up Period, (a) directly or indirectly, issue, offer, sell, agree to issue, offer or sell, solicit offers to purchase, grant any call option, warrant or other right to purchase, purchase any put option or other right to sell, pledge, borrow or otherwise dispose of any shares of our common stock or any securities convertible into or exercisable or exchangeable for shares of our common stock, or make any public announcement of any of the foregoing, (b) establish or increase any “put equivalent position” or liquidate or decrease any “call equivalent position” (in each case within the meaning of Section 16 of the Exchange Act and the rules and regulations thereunder) with respect to any shares of our common stock or any securities convertible into or exercisable or exchangeable for shares of our common stock, or (c) otherwise enter into any swap, derivative or other transaction or arrangement that transfers to another, in whole or in part, any economic consequence of ownership of any shares of our common stock or any securities convertible into or exercisable or exchangeable for shares of our common stock, whether or not such transaction is to be settled by delivery of any shares of our common stock, securities convertible into or exercisable or exchangeable for shares of our common stock, other securities, cash or other consideration.

In connection with this offering, certain of our stockholders and our directors and executive officers have agreed with the underwriters that, subject to certain customary exceptions, without the prior written consent of Guggenheim Securities, LLC on behalf of the underwriters, we and they will not, for the Lock-Up Period, directly or indirectly, (a) offer, sell, agree to offer or sell, solicit offers to purchase, grant any call option or purchase any put option with respect to, pledge, borrow or otherwise dispose of, any shares of our common stock or other securities convertible into or exercisable or exchangeable for shares of our common stock, or (b) establish or increase any “put equivalent position” or liquidate or decrease any “call equivalent position” with respect to any shares of our common stock or other securities convertible into or exercisable or exchangeable for shares of our common stock (in each case within the meaning of Section 16 of the Exchange Act, and the rules and regulations promulgated thereunder), or otherwise enter into any swap, derivative or other transaction or arrangement that transfers to another, in whole or in part, any economic consequence of ownership of shares of our common stock or other securities convertible into or exercisable or exchangeable for shares of our common stock, whether or not such transaction is to be settled by delivery of shares of our common stock or other securities convertible into or exercisable or exchangeable for shares of our common stock, other securities, cash or other consideration. Guggenheim Securities, LLC may, in its sole discretion, permit the transfer of these shares of our common stock or other securities convertible into or exercisable or exchangeable for shares of our common stock during the Lock-Up Period in whole or in part and at any time, with or without notice.

Nasdaq Capital Market Listing

In connection with this offering, our common stock has been approved for listing on the Nasdaq Capital Market under the symbol “XCUR” and is expected to begin trading on July 31, 2019.

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Price Stabilization and Short Positions

Until the distribution of the shares is completed, SEC rules may limit underwriters and selling group members from bidding for and purchasing our common stock. However, the representative may engage in transactions that stabilize the price of the common stock, such as bids or purchases to peg, fix or maintain that price.

In connection with the offering, the underwriters may purchase and sell our common stock in the open market. These transactions may include short sales, purchases on the open market to cover positions created by short sales and stabilizing transactions. Short sales involve the sale by the underwriters of a greater number of shares than they are required to purchase in the offering. “Covered” short sales are sales made in an amount not greater than the underwriters’ option described above. The underwriters may close out any covered short position by either exercising their option or purchasing shares in the open market. In determining the source of shares to close out the covered short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which they may purchase shares through the option granted to them. “Naked” short sales are sales in excess of such option. The underwriters must close out any naked short position by purchasing shares in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of our common stock in the open market after pricing that could adversely affect investors who purchase in the offering. Stabilizing transactions consist of various bids for or purchases of shares of common stock made by the underwriters in the open market prior to the closing of the offering.

Similar to other purchase transactions, the underwriters’ purchases to cover the syndicate short sales may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result, the price of our common stock may be higher than the price that might otherwise exist in the open market. The underwriters may conduct these transactions on The Nasdaq Capital Market, in the over-the-counter market or otherwise.

Neither we nor any of the underwriters make any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of our common stock. In addition, neither we nor any of the underwriters make any representation that the representatives will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.

Passive Market Making

Any underwriters who are qualified market makers on The Nasdaq Capital Market may engage in passive market making transactions in the securities on The Nasdaq Capital Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.

Electronic Distribution

In connection with the offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means, such as e-mail.

Other Relationships

The underwriters and certain of their affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. Some of the

S-23

underwriters and certain of their affiliates may in the future engage in investment banking and other commercial dealings in the ordinary course of business with us and our affiliates, for which they may in the future receive customary fees, commissions and expenses.

In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers.

Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Selling Restrictions

Notice to Prospective Investors in the European Economic Area

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive, each, a Relevant Member State, with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State, no offer of shares may be made to the public in that Relevant Member State other than:


A.	to any legal entity which is a qualified investor as defined in the Prospectus Directive;


B.	to fewer than 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), as permitted under the Prospectus Directive, subject to obtaining the prior consent of the representative; or


C.	in any other circumstances falling within Article 3(2) of the Prospectus Directive,

provided that no such offer of shares shall require us or the representative to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

Each person in a Relevant Member State who initially acquires any shares or to whom any offer is made will be deemed to have represented, acknowledged and agreed that it is a “qualified investor” within the meaning of the law in that Relevant Member State implementing Article 2(1)(e) of the Prospectus Directive. In the case of any shares being offered to a financial intermediary as that term is used in Article 3(2) of the Prospectus Directive, each such financial intermediary will be deemed to have represented, acknowledged and agreed that the shares acquired by it in the offer have not been acquired on a non-discretionary basis on behalf of, nor have they been acquired with a view to their offer or resale to, persons in circumstances which may give rise to an offer of any shares to the public other than their offer or resale in a Relevant Member State to qualified investors as so defined or in circumstances in which the prior consent of the representative has been obtained to each such proposed offer or resale.

We, the representative and each of our and the representative’s and their affiliates will rely upon the truth and accuracy of the foregoing representations, acknowledgements and agreements.

This prospectus supplement has been prepared on the basis that any offer of shares in any Relevant Member State will be made pursuant to an exemption under the Prospectus Directive from the requirement to publish a prospectus for offers of shares. Accordingly, any person making or intending to make an offer in that Relevant Member State of shares which are the subject of the offering contemplated in this prospectus supplement may only do so in circumstances in which no obligation arises for us or any of the underwriters to publish a prospectus pursuant to Article 3 of the Prospectus Directive in relation to such offer. Neither we nor the underwriters have authorized, nor do they authorize, the making of any offer of shares in circumstances in which an obligation arises for us or the underwriters to publish a prospectus for such offer.

S-24

For the purpose of the above provisions, the expression “an offer to the public” in relation to any shares in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the shares to be offered so as to enable an investor to decide to purchase or subscribe the shares, as the same may be varied in the Relevant Member State by any measure implementing the Prospectus Directive in the Relevant Member State and the expression “Prospectus Directive” means Directive 2003/71/EC (including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member States) and includes any relevant implementing measure in the Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

MiFID II Product Governance

Any person offering, selling or recommending the shares, or a distributor, should take into consideration the manufacturers’ target market assessment; however, a distributor subject to MiFID II is responsible for undertaking its own target market assessment in respect of the shares (by either adopting or refining the manufacturers’ target market assessment) and determining appropriate distribution channels.

Notice to Prospective Investors in the United Kingdom

In addition, in the United Kingdom, this document is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” (as defined in the Prospectus Directive) (i) who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended, or the Order, and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”) or otherwise in circumstances which have not resulted and will not result in an offer to the public of the shares in the United Kingdom within the meaning of the Financial Services and Markets Act 2000.

Any person in the United Kingdom that is not a relevant person should not act or rely on the information included in this document or use it as basis for taking any action. In the United Kingdom, any investment or investment activity that this document relates to may be made or taken exclusively by relevant persons.

Notice to Prospective Investors in Canada

The shares may be sold only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, as defined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in National Instrument 31-103 Registration Requirements, Exemptions and Ongoing Registrant Obligations. Any resale of the shares must be made in accordance with an exemption from, or in a transaction not subject to, the prospectus requirements of applicable securities laws.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement (including any amendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

S-25

LEGAL MATTERS

Certain legal matters in connection with this offering will be passed upon for us by Goodwin Procter LLP, Redwood City, California. Mintz, Levin, Cohn, Ferris, Glovsky and Popeo LLP, Boston, Massachusetts, is acting as counsel for the underwriters in connection with certain legal matters related to this offering.

EXPERTS

The consolidated financial statements of Exicure, Inc. as of December 31, 2018 and 2017, and for each of the years in the two-year period ended December 31, 2018, have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing. The audit report covering the December 31, 2018 consolidated financial statements refers to the adoption of Financial Accounting Standards Board Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers . The audit report covering the December 31, 2018 consolidated financial statements contains an explanatory paragraph that states that the Company has suffered recurring losses from operations and will be required to raise additional capital or alternative means of financial support to fund operations, which raise substantial doubt about its ability to continue as a going concern. The consolidated financial statements do not include any adjustments that might result from the outcome of that uncertainty.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act, of which this prospectus supplement forms a part. The rules and regulations of the SEC allow us to omit from this prospectus supplement certain information included in the registration statement. For further information about us and the securities we are offering under this prospectus supplement, you should refer to the registration statement and the exhibits and schedules filed with the registration statement. With respect to the statements contained in this prospectus supplement regarding the contents of any agreement or any other document, in each instance, the statement is qualified in all respects by the complete text of the agreement or document, a copy of which has been filed as an exhibit to the registration statement.

Because we are subject to the information and reporting requirements of the Exchange Act, we file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov .

We make available free of charge on our website our annual, quarterly and current reports, including amendments to such reports, as soon as reasonably practicable after we electronically file such material with, or furnish such material to, the SEC. Please note, however, that we have not incorporated any other information by reference from our website, other than the documents listed under the heading “Incorporation of Certain Information by Reference” on page S-27 of this prospectus supplement. In addition, you may request copies of these filings at no cost by writing or telephoning us at the following address or telephone number:

Exicure, Inc.

8045 Lamon Avenue

Suite 410

Skokie, IL 60077

(847) 673-1700

S-26

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

SEC rules permit us to incorporate information by reference in this prospectus and the applicable prospectus supplement. This means that we can disclose important information to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus and the applicable prospectus supplement, except for information superseded by information contained in this prospectus or the applicable prospectus supplement itself or in any subsequently filed incorporated document. This prospectus and the applicable prospectus supplement incorporate by reference the documents set forth below that we have previously filed with the SEC (Commission File No. 000-55764), other than information in such documents that is deemed to be furnished and not filed. These documents contain important information about us and our business and financial condition.


•	our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, filed with the SEC on March 8, 2019;


•	our Quarterly Reports on Form 10-Q and Form 10-Q/A for the fiscal quarter ended March 31, 2019, filed with the SEC on May 8, 2019 and May 14, 2019;


•	our Definitive Proxy Statement on Schedule 14A (other than information furnished rather than filed), filed with the SEC on April 30, 2019;


•	our Current Reports on Form 8-K filed with the SEC on February 1, 2019, February 22, 2019, March 14, 2019, June 17, 2019, June 27, 2019 (other than information furnished rather than filed) and July 23, 2019; and


•	the description of our common stock contained in our Form 10-12(g) filed with the SEC on March 21, 2017, and any amendment or report filed thereafter for the purpose of updating such information.

All documents that we file (but not those that we furnish) pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, after the date of the initial registration statement of which this prospectus is a part and prior to the effectiveness of the registration statement shall be deemed to be incorporated by reference into this prospectus and will automatically update and supersede the information in this prospectus, and any previously filed documents. All documents that we file (but not those that we furnish) pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus and prior to the termination of the offering of any of the securities covered under this prospectus shall be deemed to be incorporated by reference into this prospectus and will automatically update and supersede the information in this prospectus, the applicable prospectus supplement and any previously filed documents.

Any statement contained herein or in a document incorporated or deemed to be incorporated by reference in this prospectus or the applicable prospectus supplement shall be deemed to be modified or superseded for purposes of this prospectus and such applicable prospectus supplement to the extent that a statement contained in this prospectus or such applicable prospectus supplement, or in any other subsequently filed document which also is or is deemed to be incorporated by reference in this prospectus and such applicable prospectus supplement, modifies or supersedes such earlier statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus or such applicable prospectus supplement.

To obtain copies of these filings, see “Where You Can Find More Information” on page S-26 of this prospectus supplement.

S-27

PROSPECTUS

$125,000,000

Common Stock

Preferred Stock

Debt Securities

Depositary Shares

Warrants

Other Rights

Units

From time to time, we may sell up to an aggregate total offering price of $125,000,000 of our shares of Common Stock, Preferred Stock, Debt Securities, Depositary Shares, Warrants, other Rights or Units, in each case in one or more issuances and at prices and on terms that we will determine at the time of the offering.

This prospectus describes the general manner in which any of these securities may be offered using this prospectus. We will specify in an accompanying prospectus supplement the terms of the securities offered and other details regarding the offering thereof.

Our common stock is quoted on the OTC Market Group’s OTCQB ^® Market quotation system under the ticker symbol “XCUR.” On July 10, 2019, the last reported sale price of our common stock was $2.65 per share.

The securities covered by this prospectus may be sold directly by us to investors, through agents designated by us from time to time or through underwriters or dealers at prices and on terms to be determined at the time of offering. We will include in an applicable prospectus supplement the names of any underwriters or agents and any applicable commissions or discounts. Additional information on the methods of sale appears under “Plan of Distribution” in this prospectus. We will also describe in an applicable prospectus supplement the way(s) in which we expect to use the net proceeds we receive from any sale.

We are an “emerging growth company” as defined under the federal securities laws, and, as such, are eligible for reduced public company reporting requirements.

Investing in our common stock involves a high degree of risk. Before making an investment decision, please read “Risk Factors” on page 10 of this prospectus, as well as “Special Note Regarding Forward-Looking Statements” on page 4 of this prospectus. You should read the entire prospectus carefully before you make your investment decision.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus or any accompanying prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus may not be used to offer or sell any securities unless accompanied by a prospectus supplement.

The date of this prospectus is July 24, 2019.

TABLE OF CONTENTS



	Page
ABOUT THIS PROSPECTUS	1
WHERE YOU CAN FIND MORE INFORMATION	1
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	2
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	4
ABOUT THE COMPANY	6
RISK FACTORS	10
USE OF PROCEEDS	11
DIVIDEND POLICY	12
GENERAL DESCRIPTION OF SECURITIES WE MAY OFFER	13
DESCRIPTION OF CAPITAL STOCK	14
DESCRIPTION OF DEBT SECURITIES	19
DESCRIPTION OF DEPOSITARY SHARES	26
DESCRIPTION OF WARRANTS, OTHER RIGHTS AND UNITS	27
PLAN OF DISTRIBUTION	29
LEGAL MATTERS	32
EXPERTS	33

You should rely only on the information contained or incorporated by reference in this prospectus and in an applicable prospectus supplement to this prospectus. We have not authorized any other person to provide you with different or additional information. If anyone provides you with different, additional or inconsistent information, you should not rely on it. We do not take responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not making an offer to sell these securities or soliciting any offer to buy these securities in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus, any applicable prospectus supplement or any free writing prospectus we authorize to be delivered to you is accurate only as of the date of that document or any other date set forth in that document. Additionally, any information we have incorporated by reference in this prospectus or in any applicable prospectus supplement is accurate only as of the date of the document incorporated by reference or other date set forth in that document, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any sale of securities. Our business, financial condition, results of operations, cash flow and prospects may have changed since that date.

This prospectus, any applicable prospectus supplement and the information incorporated herein or therein by reference contains market data, industry statistics and other data that have been obtained or compiled from information made available by independent third parties. We have not independently verified the accuracy and completeness of such data. This prospectus, any applicable prospectus supplement and the information incorporated herein or therein by reference include trademarks, service marks and trade names owned by us or other companies. Solely for convenience, we may refer to our trademarks included or incorporated by reference in this prospectus, any applicable prospectus supplement or any free writing prospectus without the ^TM or ^® symbols, but any such references are not intended to indicate that we will not assert, to the fullest extent permitted under applicable law, our rights to our trademarks or other intellectual property. All trademarks, service marks and trade names included or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus are the property of their respective owners. Use or display by us of other parties’ trademarks, trade dress, or products in this prospectus is not intended to, and does not, imply a relationship with, or endorsements or sponsorship of, us by the trademark or trade dress owners.

Except where the context otherwise requires, when used in this prospectus, the terms “Exicure,” “we,” “our” and “us” refer to Exicure, Inc., a Delaware corporation, and, where appropriate, its subsidiaries.

ABOUT THIS PROSPECTUS

This prospectus forms a part of a registration statement that we have filed with the U.S. Securities and Exchange Commission, or the SEC, using a shelf registration process.

By using a shelf registration statement, we may, from time to time, offer and sell the securities described in this prospectus with an aggregate total offering price not exceeding $125,000,000 in one or more offerings.

This prospectus describes the general manner in which we may offer the securities described in this prospectus. Each time we sell securities pursuant to the registration statement we will provide a prospectus supplement that will contain specific information about the offering and the securities offered, and may also add, update or change information contained in this prospectus. If there is any inconsistency between information in this prospectus and any accompanying prospectus supplement, you should rely on the information in the most recent applicable prospectus supplement and documents incorporated by reference herein and therein. This prospectus may not be used to offer to sell, solicit an offer to buy or consummate a sale of our securities unless it is accompanied by a prospectus supplement.

This prospectus, together with any accompanying prospectus supplement, contains important information you should know before investing in our securities, including important information about us and the securities being offered. You should carefully read both documents, as well as the additional information contained in the documents described under “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” in both this prospectus and the applicable prospectus supplement, and in particular the annual quarterly and current reports and other documents we file with the SEC. Neither this prospectus nor any accompanying prospectus supplement is an offer to sell these securities or is soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act of 1933, as amended, or the Securities Act, with respect to the securities offered by this prospectus and the applicable prospectus supplement. This prospectus and the applicable prospectus supplement do not contain all of the information set forth in the registration statement and its exhibits and schedules in accordance with SEC rules and regulations. For further information with respect to us and the securities being offered by this prospectus and the applicable prospectus supplement, you should read the registration statement, including its exhibits and schedules. Statements contained in this prospectus and the applicable prospectus supplement, including documents that we have incorporated by reference, as to the contents of any contract or other document referred to are not necessarily complete, and, with respect to any contract or other document filed as an exhibit to the registration statement or any other such document, each such statement is qualified in all respects by reference to the corresponding exhibit. You should review the complete contract or other document to evaluate these statements. You may obtain copies of the registration statement and its exhibits through the SEC’s website or through us, at www.sec.gov or at our website www.exicuretx.com.

We file annual, quarterly and current reports, proxy statements and other documents with the SEC under the U.S. Securities Exchange Act of 1934, as amended, or the Exchange Act. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers, including us, that file electronically with the SEC. You may obtain documents that we file with the SEC through the SEC’s website or through us, at www.sec.gov or at our website www.exicuretx.com .

Our website and the information contained or connected to our website is not incorporated by reference in this prospectus or any prospectus supplement, and you should not consider it part of this prospectus or any prospectus supplement.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE


•	our Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 8, 2019;


•	our Quarterly Reports on Form 10-Q and Form 10-Q/A for the quarterly period ended March 31, 2019, filed with the SEC on May 8, 2019 and May 14, 2019;


•	our Definitive Proxy Statement on Schedule 14A (other than information furnished rather than filed), filed with the SEC on April 30, 2019;


•	our Current Reports on Form 8-K filed with the SEC on February 1, 2019, February 22, 2019, March 14, 2019, June 17, 2019 and June 27, 2019 ( other than information furnished rather than filed) ; and


•	the description of our common stock contained in our Form 10-12(g) filed with the SEC on March 21, 2017, and any amendment or report filed thereafter for the purpose of updating such information.

Documents incorporated by reference are available from us without charge, excluding all exhibits unless specifically incorporated by reference as an exhibit to this prospectus and the applicable prospectus supplement.

Prospective investors may obtain documents incorporated by reference in this prospectus and the applicable prospectus supplement by requesting them in writing or by telephone from us at our executive offices at:

Exicure, Inc.

8045 Lamon Avenue

Suite 410

Skokie, IL 60077

(847) 673-1700

Attention: Investor Relations and Corporate Communications

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, together with any accompanying prospectus supplement, includes and incorporates by reference “forward-looking statements” within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and releases issued by the SEC and within the meaning of Section 27A of the Securities Act, and Section 21E of the Exchange Act. All statements other than statements of historical fact are “forward-looking statements” for purposes of this prospectus. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “will,” “would,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “intend,” “predict,” “seek,” “contemplate,” “project,” “continue,” “potential,” “ongoing,” “goal,” or the negative of these terms or other comparable terminology. These forward-looking statements include, but are not limited to, statements about:


•	the initiation, timing, progress and results of our research and development programs, preclinical studies, clinical trials and Investigational New Drug application, or IND, Investigational Medicinal Product Dossier, Clinical Trial Application, or CTA, New Drug Application, or NDA, or other regulatory submissions;


•	our receipt and timing of any milestone payments or royalties under any current or future research collaboration and license agreements or arrangements;


•	our ability to identify and develop therapeutic candidates for treatment of additional disease indications;


•	our or a current or future collaborator’s ability to obtain and maintain regulatory approval of any of our therapeutic candidates;


•	the rate and degree of market acceptance of any approved therapeutic candidates;


•	the commercialization of any approved therapeutic candidates;


•	our ability to establish and maintain collaborations and retain commercial rights for our therapeutic candidates in the collaborations;


•	the implementation of our business model and strategic plans for our business, technologies and therapeutic candidates;


•	our estimates of our expenses, ongoing losses, future revenue and capital requirements, including our expectations relating to our need for additional financing;


•	our ability to obtain additional funds for our operations;


•	our ability to obtain and maintain intellectual property protection for our technologies and therapeutic candidates and our ability to operate our business without infringing the intellectual property rights of others;


•	our reliance on third parties to conduct our preclinical studies and clinical trials


•	the ability of our third party supply and manufacturing partners to supply the materials and components for, and manufacture, our research and development, preclinical and clinical trial supplies;


•	our ability to attract and retain qualified key management and technical personnel;


•	our expectations regarding the time during which we will be an emerging growth company under the Jumpstart Our Business Startups Act of 2012;


•	our financial performance;


•	In Part II., Item 9A. Controls and Procedures of our Annual Report on Form 10-K for the year ended December 31, 2018, which is incorporated by reference in this prospectus, the statements regarding our internal controls; and


•	the impact of government regulation and developments relating to our competitors or our industry.

These statements relate to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. In evaluating such forward-looking statements, you should specifically consider various factors that may cause actual results to differ materially from current expectations, including the risks and uncertainties outlined under the heading “Risk Factors” contained in this prospectus and any related free writing prospectus, and in any other documents incorporated herein or therein (including in our most recent annual report on Form 10-K, subsequent quarterly reports on Form 10-Q and other filings we make with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act).

Any forward-looking statement in this prospectus reflects our current view with respect to future events and is subject to these and other risks, uncertainties and assumptions relating to our business, results of operations, industry and future growth. Given these uncertainties, you should not place undue reliance on these forward-looking statements. No forward-looking statement is a guarantee of future performance. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This prospectus, together with any accompanying prospectus supplement, also contains estimates, projections and other information concerning our industry, our business and the markets for certain therapeutics, including data regarding the estimated size of those markets, their projected growth rates and the incidence of certain medical conditions. Information that is based on estimates, forecasts, projections or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained these industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources. In some cases, we do not expressly refer to the sources from which these data are derived.

ABOUT THE COMPANY

The following highlights information about us and our business contained elsewhere or incorporated by reference in this prospectus. It is not complete and does not contain all of the information that you should consider before investing in any of our securities. You should carefully read this prospectus together with the more detailed information incorporated by reference in this prospectus.

Overview

We are a clinical-stage biotechnology company developing therapeutics for immuno-oncology, inflammatory diseases and genetic disorders based on our proprietary Spherical Nucleic Acid, or SNA, technology. SNAs are nanoscale constructs consisting of densely packed synthetic nucleic acid sequences that are radially arranged in three dimensions. We believe the design of our SNAs gives rise to distinct chemical and biological properties that may provide advantages over other nucleic acid therapeutics and enable therapeutic activity outside of the liver. We have advanced SNA therapeutic candidates through three Phase 1 clinical trials. These include AST-008 addressing immuno-oncology, and XCUR17 and AST-005 addressing psoriasis. We have also shown in preclinical studies that SNAs may have therapeutic potential in neurology, ophthalmology, pulmonology, and gastroenterology.

Clinical development programs

Immuno-oncology

AST-008 is an SNA consisting of toll-like receptor 9, or TLR9, agonists designed for immuno-oncology applications. TLR9 agonists bind to and activate TLR9 receptors. We believe AST-008 may be used for immuno-oncology applications as a monotherapy or in combination with checkpoint inhibitors. Checkpoint inhibitors are therapeutics that prevent tumors from evading destruction by the immune system. We have observed that administration of AST-008 as a monotherapy can have anti-tumor activity in mouse models of colon cancer, breast cancer, lymphoma and melanoma. We have also observed that, in preclinical studies in a variety of tumor models, AST-008, applied in combination with certain checkpoint inhibitors, exhibited anti-tumor responses and survival rates that were greater than those demonstrated by checkpoint inhibitors alone. We have also demonstrated that AST-008 was active when administered subcutaneously, intratumorally or intravenously, in both prevention and established mouse tumor models. The administration of AST-008 also produced localized as well as abscopal anti-tumor activity in mouse cancer models. Additionally, administration of AST-008 in combination with certain checkpoint inhibitors conferred adaptive immunity in breast and colon cancer mouse models.

During the fourth quarter of 2018 the FDA opened the IND for AST-008 and informed the Company that our proposed Phase1b/2 trial may proceed. During the first half of 2019, we opened five clinical sites and began recruiting and dosing patients in that trial. This is a Phase 1b/2, open-label, multi-center trial designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary efficacy of intratumoral AST-008 injections alone and in combination with intravenous pembrolizumab in patients with advanced solid tumors. We planned to recruit patients with advanced or metastatic: Merkel cell carcinoma, head and neck squamous cell carcinoma, cutaneous squamous cell carcinoma and melanoma. The primary outcome measure is the safety and tolerability of AST-008 alone and in combination with pembrolizumab. Secondary outcomes include the recommended Phase 2 dose and disease assessment with RECIST 1.1.

Inflammatory diseases

XCUR17

XCUR17, is an SNA that targets the mRNA that encodes interleukin 17 receptor alpha, or IL-17RA, a protein that is considered essential in the initiation and maintenance of psoriasis. Although the availability of inhibitors of TNF revolutionized the systemic treatment of severe psoriasis, studies of disease pathogenesis have shifted attention to the IL-17 pathway, in which IL-17RA is a key driver of psoriasis. Our strategy is to reduce the levels of IL-17RA in the skin by topically applying XCUR17. In preclinical studies, XCUR17 inhibited IL-17RA in the

keratinocytes of the skin.

We filed a CTA for a Phase 1 clinical trial of XCUR17 in patients with psoriasis in Germany in the third quarter of 2017 and we began dosing patients in April 2018. The Phase 1 clinical trial, which had final patient visits in the fourth quarter of 2018, was a randomized, double-blinded, placebo-controlled trial in twenty-one patients with mild to moderate chronic plaque psoriasis designed to assess the safety of XCUR17 formulated as a topical gel, and to evaluate early signs of efficacy. All patients received three strengths of XCUR17 gel, a vehicle gel, and a positive comparator (Daivonex® cream), which were all applied on different areas of psoriatic skin within each individual patient.

In the fourth quarter of 2018 we reported results from the Phase 1 trial of XCUR17. In the case of XCUR17, of the twenty-one treated patients, eleven treated with the highest strength XCUR17 gel were observed to have a reduction in redness and improvement in healing as determined by blinded physician assessments. Further, the highest strength XCUR17 gel showed a statistically significant improvement in psoriasis symptoms versus the vehicle gel. By comparison, seventeen of the twenty-one patients treated with the positive comparator showed a clinical response, while four patients treated with the placebo vehicle had a clinical response.

Dermelix License Agreement

On February 17, 2019 we entered into a License and Development Agreement, or the Dermelix License Agreement, with DERMELIX, LLC, d/b/a Dermelix Biotherapeutics. Under the terms of agreement, Dermelix licensed worldwide rights to research, develop, and commercialize Exicure’s technology for the treatment of Netherton Syndrome and, at Dermelix’s option, up to five additional rare skin indications.

Dermelix will initially develop a targeted therapy for the treatment of Netherton Syndrome (NS). NS is a rare and severe autosomal recessive disorder caused by loss-of-function mutations in the SPINK5 gene, which encodes the serine protease inhibitor LEKT1 involved in skin barrier function. NS affects approximately 1 in 200,000 children born each year, and is characterized by severely inflamed, red, scaled, itchy skin, and patients are at increased risk of mortality in the first year of life due to recurrent infections and dehydration as a result of the impaired skin barrier. Currently, there are no approved treatments for NS patients and off-label use of standard of care treatments are of limited utility.

Under the terms of the Dermelix License Agreement, Exicure received an upfront payment of $1 million at closing of the transaction and will receive an additional $1 million upon the exercise of each of the five options granted to Dermelix. Exicure will be responsible for conducting the early stage development for each indication up to IND enabling toxicology studies. Dermelix will undertake subsequent development, commercial activities and financial responsibility. For each of NS as well as any additional licensed product for which Dermelix exercises one of its options, Exicure is eligible to receive potential payments totaling up to $13.5 million upon achievement of certain development and regulatory milestones and up to $152.5 million upon achievement of certain sales milestones per indication in each of six indications. In addition, Exicure will receive low double-digit royalties on annual net sales for SNA therapeutics developed.

Other Inflammatory Diseases

Genetic disorders

AST-005

On December 2, 2016, we entered into a research collaboration, option and license agreement with Purdue Pharma L.P., referred to as the Purdue Collaboration. As part of our collaboration with Purdue, a Phase 1b clinical trial was conducted in Germany to evaluate the effect of AST-005 gel in patients with chronic plaque psoriasis. The trial demonstrated that AST-005 is safe and tolerable in patients at higher doses than were previously studied, however, the study did not result in a statistically significant decrease in echo lucent band thickness, one of the key indicators of efficacy in patients with psoriasis. In April 2018, Purdue notified the Company it had declined to exercise its option to develop AST-005 at that time, but that it also intended to retain rights relating to the TNF target, and Purdue reserved its right to continue joint development, with Exicure, of new anti-TNF drug candidates and to retain its exclusivity and other rights to AST-005.

Our Strategy

We intend to build a leading nucleic acid therapeutics company based on our proprietary SNA technology. The key elements of our strategy are:


•	Advance AST-008 through clinical development for immuno-oncology applications;


•	Continue research and development in neurological applications


•	Advance SNA platform in dermatological indications.


•	Use our proprietary SNA technology to develop additional therapeutic candidates;


•	Enter into additional partnerships to accelerate development and commercialization of our SNA therapeutic candidates; and


•	Build, enhance and protect our proprietary SNA intellectual property.

Our Clinical Development Programs

The table below sets forth the stage of development of our SNA therapeutic candidates as of July 10, 2019:

TLR9 = Toll-like Receptor 9; IL17RA = Interleukin 17 Receptor Alpha

Our Corporate Information

We were originally incorporated in the State of Delaware on February 6, 2017 under the name “Max-1 Acquisition Corporation.” Prior to the Merger (as defined below), Max-1 was a “shell” company registered under the Securities Exchange Act of 1934, as amended, or the Exchange Act, with no specific business plan or purpose until it began operating the business of Exicure Operating Company (Exicure OpCo) through a transaction on September 26, 2017, or the Merger. Exicure OpCo was originally formed as a limited liability company under the name AuraSense Therapeutics, LLC in the State of Delaware in June 2011 and was a clinical-stage biotechnology company developing gene regulatory and immuno-oncology therapeutics based on its proprietary SNA technology. AuraSense Therapeutics, LLC was subsequently converted into AuraSense Therapeutics, Inc., a Delaware corporation, on July 9, 2015, and changed its name on the same date to Exicure, Inc. Immediately after giving effect to the Merger and the initial closing of the 2017 Private Placement, the business of Exicure OpCo became our business.

RISK FACTORS

An investment in our securities is speculative in nature and involves a high degree of risk. Before deciding whether to invest in our securities, you should carefully consider the discussion of the material risks of investing in our securities contained in our filings with the SEC, as well as in the applicable prospectus supplement, in evaluating us and our business and prospects before you decide to purchase any of our securities. You should also be aware that this document and other public statements we make may contain statements that do not relate strictly to historical fact, any of which may be forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995, and should take into account the considerations relating to such statements discussed under “Risk Factors” or any similar heading in the applicable prospectus supplement and in our filings we make with the SEC including (i) our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, which is on file with the SEC and is incorporated herein by reference and (ii) other documents we file with the SEC that are deemed incorporated by reference into this prospectus. Any of the risks and uncertainties set forth therein could materially and adversely affect our business, results of operations, cash flow and financial condition, which in turn could materially and adversely affect the trading price or value of our securities. As a result, you could lose all or part of your investment.

The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business operations.

USE OF PROCEEDS

Unless otherwise described in the applicable prospectus supplement, we intend to use the net proceeds from the sale of any securities described in this prospectus for preclinical studies and clinical trials, with the remainder of any net proceeds from sales of securities being used for continued technology platform development, working capital and general corporate purposes. We may set forth additional information concerning our expected use of net proceeds from sales of securities in the applicable prospectus supplement relating to the specific offering. Pending use of net proceeds as described above, we may invest net proceeds in interest-bearing, investment-grade securities.

DIVIDEND POLICY

We currently intend to retain future earnings, if any, for use in the operation of our business and to fund future growth. We have never declared or paid cash dividends on our common stock and we do not intend to pay any cash dividends on our common stock for the foreseeable future. Any future determination related to our dividend policy will be made at the discretion of our board of directors in light of conditions then-existing, including factors such as our results of operations, financial condition and requirements, business conditions and covenants under any applicable contractual arrangements.

GENERAL DESCRIPTION OF SECURITIES WE MAY OFFER

We may offer shares of common or preferred stock, various series of senior or subordinated debt securities, depositary shares, warrants, other rights to purchase securities or units consisting of combinations of the foregoing, in each case from time to time under this prospectus, together with the applicable prospectus supplement, at prices and on terms to be determined by market conditions at the time of offering. This prospectus provides you with a general description of the securities we may offer. At the time we offer a particular type or series of securities, we will provide an applicable prospectus supplement describing the specific amounts, prices and other important terms of the securities, including, to the extent applicable:


•	designation or classification;


•	aggregate principal amount or aggregate offering price;


•	voting or other rights;


•	rates and times of payment of interest, dividends or other payments;


•	liquidation preference;


•	original issue discount;


•	maturity;


•	ranking;


•	restrictive covenants;


•	redemption, conversion, exercise, exchange, settlement or sinking fund terms, including prices or rates, and any provisions for changes to or adjustments in such prices or rates and in the securities or other property receivable upon conversion, exercise, exchange or settlement;


•	any securities exchange or market listing arrangements; and


•	important U.S. federal income tax considerations.

This prospectus may not be used to offer or sell securities unless accompanied by an applicable prospectus supplement. The applicable prospectus supplement may add, update or change information contained in this prospectus or in documents incorporated by reference in this prospectus. You should read the prospectus supplement related to any securities being offered.

We may sell the securities directly to or through underwriters, dealers or agents. We and our underwriters, dealers or agents reserve the right to accept or reject all or part of any proposed purchase of securities. If we do offer securities through underwriters or agents, we will include in the applicable prospectus supplement (i) the names of the underwriters or agents and applicable fees, discounts and commissions to be paid to them; (ii) details regarding over-allotment options, if any; and (iii) net proceeds to us.

The following descriptions are not complete and may not contain all the information you should consider before investing in any securities we may offer hereunder; they are summarized from, and qualified by reference to, our amended and restated certificate of incorporation, bylaws and the other documents referred to in the descriptions, all of which are or will be publicly filed with the SEC, as applicable. See “Where You Can Find More Information.”

DESCRIPTION OF CAPITAL STOCK

The following summary description sets forth some of the general terms and provisions of our capital stock. Because this is a summary description, it does not contain all of the information that may be important to you. For a more detailed description of our common stock, you should refer to the applicable provisions of the General Corporation Law of the State of Delaware, or the DGCL, and our certificate of incorporation and bylaws as in effect at the time of any offering. Copies of our Amended and Restated Certificate of Incorporation, as amended, and our Amended and Restated Bylaws are included as exhibits to the registration statement of which this prospectus forms a part.

General

We have authorized capital stock consisting of 200,000,000 shares of common stock and 10,000,000 shares of preferred stock. As of July 10, 2019, we had 44,369,790 shares of common stock issued and outstanding, and no shares of preferred stock issued and outstanding. Unless stated otherwise, the following discussion summarizes the terms and provisions of our amended and restated certificate of incorporation and our amended and restated bylaws, each of which has been publicly filed with the SEC.

Common Stock . The holders of shares of our common stock are entitled to one vote per share on all matters to be voted upon by our stockholders and there are no cumulative rights. Subject to preferences that may be applicable to any outstanding preferred stock, the holders of shares of our common stock are entitled to receive ratably any dividends that may be declared from time to time by our board of directors out of funds legally available for that purpose. In the event of our liquidation, dissolution or winding up, the holders of shares of our common stock are entitled to share ratably in all assets remaining after payment of liabilities, subject to prior distribution rights of preferred stock then outstanding. Our common stock has no preemptive or conversion rights or other subscription rights. There are no redemption or sinking fund provisions applicable to our common stock. The outstanding shares of our common stock are fully paid and non-assessable, and any shares of our common stock to be issued upon an offering pursuant to this prospectus will be fully paid and nonassessable upon issuance.

We have never paid cash dividends on our common stock. Moreover, we do not anticipate paying periodic cash dividends on our common stock for the foreseeable future. Any future determination about the payment of dividends will be made at the discretion of our board of directors and will depend upon our earnings, if any, capital requirements, operating and financial conditions and on such other factors as our board of directors deems relevant.

Preferred Stock . The following description of our preferred stock and the description of the terms of any particular series of our preferred stock that we choose to issue hereunder are not complete. These descriptions are qualified in their entirety by reference to our amended and restated certificate of incorporation and the certificate of designation, if and when adopted by our board of directors, relating to that series. The rights, preferences, privileges and restrictions of the preferred stock of each series will be fixed by the certificate of designation relating to that series.

We currently have no shares of preferred stock outstanding. Our board of directors has the authority, without further action by the stockholders, to issue up to 10,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges and restrictions granted to or imposed upon the preferred stock. Any or all of these rights may be greater than the rights of our common stock.

Our board of directors, without stockholder approval, can issue preferred stock with voting, conversion or other rights that could negatively affect the voting power and other rights of the holders of our common stock. Preferred stock could thus be issued quickly with terms calculated to delay or prevent a change in control of us or make it more difficult to remove our management. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of our common stock.

Our board of directors may specify the following characteristics of any preferred stock:


•	the maximum number of shares;


•	the designation of the shares;


•	the annual dividend rate, if any, whether the dividend rate is fixed or variable, the date or dates on which dividends will accrue, the dividend payment dates, and whether dividends will be cumulative;


•	the price and the terms and conditions for redemption, if any, including redemption at our option or at the option of the holders, including the time period for redemption, and any accumulated dividends or premiums;


•	the liquidation preference, if any, and any accumulated dividends upon the liquidation, dissolution or winding up of our affairs;


•	any sinking fund or similar provision, and, if so, the terms and provisions relating to the purpose and operation of the fund;


•	the terms and conditions, if any, for conversion or exchange of shares of any other class or classes of our capital stock or any series of any other class or classes, or of any other series of the same class, or any other securities or assets, including the price or the rate of conversion or exchange and the method, if any, of adjustment;


•	the voting rights; and


•	any or all other preferences and relative, participating, optional or other special rights, privileges or qualifications, limitations or restrictions.

Any preferred stock to be issued upon an offering pursuant to this prospectus will be fully paid and nonassessable upon issuance.

Outstanding Warrants . As of July 10, 2019, we had outstanding warrants as follows:


•	32 warrants that entitle holders to purchase an aggregate of 413,320 shares of common stock, with a term of three years and an exercise price of $3.00 per share.

Options. As of July 10, 2019, we had outstanding options to purchase common stock as follows:


•	5,078,873 reserved for issuance upon exercise of outstanding stock options granted under Company incentive plans and 729,368 available for future issuance pursuant to our existing stock incentive plan.

Other Convertible Securities As of July 10, 2019, other than the securities described above, we do not have any outstanding convertible securities.

Anti-Takeover Effects of Provisions of Our Charter Documents

Our amended and restated certificate of incorporation provides for our board of directors to be divided into three classes serving staggered terms. Approximately one-third of the board of directors will be elected each year. The provision for a classified board could prevent a party who acquires control of a majority of our outstanding voting stock from obtaining control of our board of directors until the second annual stockholders meeting following the date the acquirer obtains the controlling stock interest. The classified board provision could discourage a potential acquirer from making a tender offer or otherwise attempting to obtain control of us and could increase the likelihood that incumbent directors will retain their positions. Our amended and restated certificate of incorporation provides that directors may be removed only for cause by the affirmative vote of the holders of at least 66 and 2/3% of the voting power of all of our outstanding stock.

Our amended and restated certificate of incorporation provides that certain amendments of our certificate of incorporation and amendments by our stockholders of our amended and restated bylaws require the approval of at least 66 and 2/3% of the voting power of all of our outstanding stock. These provisions could discourage a potential acquirer from making a tender offer or otherwise attempting to obtain control of our company and could delay changes in management.

Our amended and restated certificate of incorporation also provides that, unless we consent in writing to an alternative forum, the Court of Chancery of the State of Delaware will be the sole and exclusive forum for any derivative action or proceeding brought on our behalf, any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers, employees or agents to us or our stockholders, any action asserting a claim arising pursuant to any provision of the DGCL, our amended and restated certificate of incorporation or our amended and restated bylaws or any action asserting a claim that is governed by the internal affairs doctrine, in each case subject to the Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein and the claim not being one which is vested in the exclusive jurisdiction of a court or forum other than the Court of Chancery or for which the Court of Chancery does not have subject matter jurisdiction. However, this exclusive forum provision would not apply to suits brought to enforce a duty or liability created by the Exchange Act. Furthermore, this provision applies to Securities Act claims and Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all suits brought to enforce any duty or liability created by the Securities Act or the rules and regulations thereunder. Accordingly, there is uncertainty as to whether a court would enforce such provision, and our stockholders will not be deemed to have waived our compliance with the federal securities laws and the rules and regulations thereunder. This exclusive-forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers or other employees, which may discourage lawsuits against us and our directors, officers and other employees.

Our amended and restated bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of our stockholders, including proposed nominations of persons for election to our board of directors. At an annual meeting, stockholders may only consider proposals specified in the notice of meeting or brought before the meeting by or at the direction of our board of directors. Additionally, at an annual meeting, stockholders may only consider nominations brought before the meeting by or at the direction of our board of directors. Stockholders may also consider a proposal or nomination by a person who was a stockholder at the time of giving notice and at the time of the meeting, who is entitled to vote at the meeting and who has complied with the notice requirements of our amended and restated bylaws in all respects. The amended and restated bylaws do not give our board of directors the power to approve or disapprove stockholder nominations of candidates or proposals regarding other business to be conducted at a special or annual meeting of our stockholders. However, our amended and restated bylaws may have the effect of precluding the conduct of certain business at a meeting if the proper procedures are not followed. These provisions may also discourage or deter a potential acquirer from conducting a solicitation of proxies to elect the acquirer’s own slate of directors or otherwise attempting to obtain control of our company.

Our amended and restated bylaws provide that a special meeting of our stockholders may be called only by our Secretary and at the direction of our board of directors by resolution adopted by a majority of our board of directors. Because our stockholders do not have the right to call a special meeting, a stockholder could not force stockholder consideration of a proposal over the opposition of our board of directors by calling a special meeting of stockholders prior to such time as a majority of our board of directors, the chairperson of our board of directors, the president or the chief executive officer believed the matter should be considered or until the next annual meeting provided that the requestor met the notice requirements. The restriction on the ability of stockholders to call a special meeting means that a proposal to replace our board of directors also could be delayed until the next annual meeting.

Our amended and restated certificate of incorporation and amended and restated bylaws do not allow our stockholders to act by written consent without a meeting. Without the availability of stockholder action by written consent, a holder controlling a majority of our capital stock would not be able to amend our amended and restated bylaws or remove directors without holding a stockholders’ meeting.

Anti-Takeover Effects of Delaware Law

We are subject to the provisions of Section 203 of the DGCL, or Section 203. Under Section 203, we would generally be prohibited from engaging in any business combination with any interested stockholder for a period of three years following the time that this stockholder became an interested stockholder unless:


•	prior to this time, our board of directors approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

•

upon consummation of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced, excluding shares owned by persons who are directors and also officers, and by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or


•	at or subsequent to such time, the business combination is approved by our board of directors and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 and 2/3% of the outstanding voting stock that is not owned by the interested stockholder.

Under Section 203, a “business combination” includes:


•	any merger or consolidation involving the corporation and the interested stockholder;


•	any sale, transfer, pledge or other disposition of 10% or more of the assets of the corporation involving the interested stockholder;


•	any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder, subject to limited exceptions;


•	any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or


•	the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.

In general, Section 203 defines an interested stockholder as an entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by such entity or person.

The provisions of Delaware law and our amended and restated certificate of incorporation and amended and restated bylaws could have the effect of discouraging others from attempting hostile takeovers and, as a consequence, they may also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. These provisions may also have the effect of preventing changes in management. It is possible that these provisions may make it more difficult to accomplish transactions that stockholders may otherwise deem to be in their best interests.

Following such time, if any, as our capital stock is listed on a national securities exchange or is held of record by more than 2,000 stockholders, we will be subject to the provisions of Section 203 of the DGCL, as amended.

Stock Exchange Listing

Our common stock is currently quoted on OTC Market Group’s OTCQB ^® Market quotation system under the ticker symbol “XCUR.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company, LLC.

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement, summarizes the material features, terms and provisions of any debt securities that we may offer under this prospectus. This summary does not purport to be exhaustive and may not contain all of the information that is important to you. Therefore, you should read the applicable prospectus supplement relating to the debt securities and any other offering materials that we may provide. We may issue debt securities from time to time, in one or more series, as senior, subordinated or junior subordinated, convertible or non-convertible and secured or unsecured debt. Any senior debt securities will rank equally with any unsubordinated debt. Subordinated debt securities will rank equally with any other subordinated debt of the same ranking we may issue. Convertible debt securities will be convertible into or exchangeable for our common stock or other securities at predetermined conversion rates, and conversion may be mandatory or at the holder’s option.

Debt securities will be issued under one or more indentures, which are instruments between us and a national banking association or other eligible party acting as trustee on behalf of holders of debt securities. Following is a summary of certain general features of debt securities we may offer; we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement, which may differ in certain respects from the terms we describe below. You should read the applicable prospectus supplement, any free writing prospectus we may authorize and the indentures, supplemental indentures and forms of debt securities relating to any series of debt securities we may offer.

General . Except as we may otherwise provide in the applicable prospectus supplement, the relevant indenture will provide that debt securities may be issued from time to time in one or more series. The indenture will not limit the amount of debt securities that may be issued thereunder, and will provide that the specific terms of any series of debt securities shall be set forth in, or determined pursuant to, an authorizing resolution, an officers’ certificate or a supplemental indenture, if any, relating to such series.

We will describe in each applicable prospectus supplement the following terms relating to any series of debt securities, including, to the extent applicable:


•	the title or designation;


•	whether the debt securities will be secured or unsecured, and the terms of any security;


•	whether the debt securities will be subject to subordination, and any terms thereof;


•	any limit upon the aggregate principal amount;


•	the interest rate, which may be fixed or variable, or the method for determining the rate, the date interest will begin to accrue, the date or dates interest will be payable and the record dates for interest payment dates or the method for determining them;

•

the manner in which the amounts of payment of principal of, premium (if any) or interest on the debt securities will be determined, if these amounts may be determined by reference to an index based on a currency or currencies other than that in which the debt securities are denominated or designated to be payable or by reference to a commodity, commodity index, stock exchange index or financial index;


•	the currency of denomination;


•	if payments of principal of, premium (if any) or interest will be made in one or more currencies or currency units other than that or those in which the debt securities are denominated, the manner in which the exchange rate with respect to these payments will be determined;


•	the place or places where the principal of, premium (if any) and interest will be payable, where debt

securities of any series may be presented for registration of transfer, exchange or conversion, and where notices and demands to or upon the Company in respect of the debt securities may be made;


•	the form of consideration in which principal of, premium (if any) or interest will be paid;


•	the terms and conditions upon which we may redeem the debt securities;


•	any obligation we have to redeem or purchase the debt securities pursuant to any sinking fund, amortization or analogous provisions or at the option of a holder;


•	the dates on which and the price or prices at which we will repurchase the debt securities at the option of holders and other detailed terms and provisions of these obligations;


•	the denominations in which the debt securities will be issued, if other than denominations of $1,000 and any integral multiple thereof;


•	the portion of principal amount payable upon declaration of acceleration of the maturity date, if other than the principal amount;


•	whether the debt securities are to be issued at any original issuance discount and the amount of discount with which the debt securities may be issued;


•	whether the debt securities will be issued in certificated or global form and, in such case, the depositary and the terms and conditions, if any, upon which interests in such global security or securities may be exchanged in whole or in part for the individual securities represented thereby;


•	provisions, if any, for defeasance in whole or in part and any addition or change to provisions related to satisfaction and discharge;


•	the form of the debt securities;


•	the terms and conditions upon which convertible debt securities will be convertible or exchangeable into our securities or property or those of another person, if at all, and any additions or changes, if any, to permit or facilitate the same;


•	any provisions granting special rights to holders upon the occurrence of specified events;


•	any restriction or condition on transferability;


•	any addition or change in the provisions related to compensation and reimbursement of the trustee;


•	any addition to or change in the events of default described in this prospectus or in the indenture and any change in the acceleration provisions so described;


•	whether the debt securities will restrict our ability to pay dividends, or will require us to maintain any asset ratios or reserves;


•	whether we will be restricted from incurring any additional indebtedness;


•	any addition to or change in the covenants described in this prospectus or in the indenture, including terms of any restrictive covenants; and


•	any other terms which may modify or delete any provision of the indenture.

We may issue debt securities that provide for an amount less than their stated principal amount to be due and payable upon declaration of acceleration of their maturity pursuant to the terms of the indenture. We will provide you with information on the U.S. federal income tax considerations and other special considerations applicable to any debt securities in the applicable prospectus supplement.

Conversion or Exchange Rights . We will set forth in the applicable prospectus supplement the terms, if any, on which a series of debt securities may be convertible into or exchangeable for our common stock or other securities. We will include provisions as to whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or other securities that the holders of debt securities receive would be subject to adjustment.

Consolidation, Merger or Sale; No Protection in Event of a Change of Control or Highly Leveraged Transaction . Except as we may otherwise provide in the applicable prospectus supplement, the indenture will provide that we may not merge or consolidate with or into another entity, or sell other than for cash or lease all or substantially all our assets to another entity, or purchase all or substantially all the assets of another entity unless we are the surviving entity or, if we are not the surviving entity, the successor, transferee or lessee entity expressly assumes all of our obligations under the indenture or the debt securities, as appropriate.

Unless we state otherwise in the applicable prospectus supplement, the debt securities will not contain any provisions that may afford holders additional protection in the event we experience a change of control or in the event of a highly-leveraged transaction (whether or not such transaction results in a change of control), which could adversely affect them.

Events of Default Under the Indenture . Except as we may otherwise provide in the applicable prospectus supplement, the following will be events of default under the indenture with respect to any series of debt securities that we may issue:


•	if we fail to pay interest when due and our failure continues for 90 days and the time for payment has not been extended or deferred;


•	if we fail to pay the principal, or premium, if any, when due whether by maturity or called for redemption;


•	if we fail to pay a sinking fund installment, if any, when due and our failure continues for 30 days;


•	if we fail to observe or perform any other covenant relating to the debt securities, other than a covenant specifically relating to and for the benefit of holders of another series of debt securities, and our failure continues for 90 days after we receive written notice from the trustee or holders of not less than a majority in aggregate principal amount of the outstanding series; and


•	if specified events of bankruptcy, insolvency or reorganization occur as to the Company.

No event of default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) will necessarily constitute an event of default with respect to any other series. The occurrence of an event of default may constitute an event of default under any credit or similar agreements we may have in existence from time to time. In addition, the occurrence of certain events of default or an acceleration under the indenture may constitute an event of default under certain of our other indebtedness outstanding from time to time.

Except as we may otherwise provide in the applicable prospectus supplement, if an event of default with respect to debt securities of any series at the time outstanding occurs and is continuing, then the trustee or the holders of not less than a majority in principal amount of the outstanding series may, by a notice in writing to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal (or, if the debt securities are discount securities, that portion of the principal amount as may be specified in the terms of such securities) of and premium and accrued and unpaid interest, if any, on all such debt securities. Before a judgment or decree for

payment of the money due has been obtained with respect to any series, the holders of a majority in principal amount of that series (or, at a meeting of holders at which a quorum is present, the holders of a majority in principal amount represented at such meeting) may rescind and annul the acceleration if all events of default, other than the non-payment of accelerated principal, premium, if any, and interest, if any, have been cured or waived as provided in the applicable indenture (including payments or deposits in respect of principal, premium or interest that had become due other than as a result of such acceleration) and the Company has deposited with the trustee or paying agent a sum sufficient to pay all amounts owed to the trustee under the indenture, all arrears of interest, if any, and the principal and premium, if any, on the debt securities that have become due other than by such acceleration. We refer you to the applicable prospectus supplement relating to any discount securities for the particular provisions relating to acceleration of a portion of the principal amount thereof upon the occurrence of an event of default.

Subject to the terms of the indenture, and except as we may otherwise provide in a prospectus supplement, if an event of default under the indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to that series, provided that, subject to the terms of the indenture, the trustee need not take any action that it believes, upon the advice of counsel, might involve it in personal liability or might be unduly prejudicial to holders not involved in the proceeding.

Except as we may otherwise provide in the applicable prospectus supplement, a holder of the debt securities of any series will only have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies if:


•	the holder previously has given written notice to the trustee of a continuing event of default with respect to that series;


•	the holders of at least a majority in aggregate principal amount outstanding of that series have made written request, and such holders have offered reasonable indemnity to the trustee to institute the proceeding as trustee; and


•	the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount outstanding of that series (or at a meeting of holders at which a quorum is present, the holders of a majority in principal amount of such series represented at such meeting) other conflicting directions within 60 days after the notice, request and offer.

Except as we may otherwise provide in the applicable prospectus supplement, these limitations will not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, them.

We will periodically file statements with the applicable trustee regarding our compliance with specified covenants in the applicable indenture.

Modification of Indenture; Waiver . Except as we may otherwise provide in the applicable prospectus supplement, we and the trustee may, without the consent of any holders of any series, execute a supplemental indenture to change the indenture with respect to specific matters, including, among other things:


•	to surrender any right or power conferred upon us;


•	to provide, change or eliminate any restrictions on payment of principal of or premium, if any; provided that any such action shall not adversely affect the interests of the holders of debt securities of any series in any material respect;


•	to change or eliminate any of the provisions of the indenture; provided that any such change or elimination shall become effective only when there is no outstanding debt security created prior to the execution of such supplemental indenture that is entitled to the benefit of such provision and as to which such supplemental indenture would apply;


•	to evidence any successor entity to us;


•	to evidence and provide for the acceptance of appointment by a successor trustee with respect to one or more series of debt securities and to add or change provisions of the indenture to facilitate the administration thereof by more than one trustee;

•

to cure any ambiguity, mistake, manifest error, omission, defect or inconsistency in the indenture or to conform the text of any provision in the indenture or in any supplemental indenture to any description thereof in the applicable section of a prospectus, prospectus supplement or other offering document that was intended to be a verbatim recitation of a provision of the indenture or of any supplemental indenture;


•	to add to or change or eliminate any provision of the indenture as shall be necessary or desirable in accordance with any amendments to the U.S. Trust Indenture Act of 1939;


•	to make any change in any series of debt securities that does not adversely affect in any material respect the interests of the holders thereof; and


•	to supplement any of the provisions of the indenture to such extent as shall be necessary to permit or facilitate the defeasance and discharge of any series of debt securities; provided that any such action shall not adversely affect the interests of holders of any debt securities.

In addition, and except as we may otherwise provide in the applicable prospectus supplement, under the indenture the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount outstanding (or, at a meeting of holders of such series at which a quorum is present, the holders of a majority in principal amount represented at such meeting) that is affected. We and the trustee may, however, make the following changes only with the consent of each holder of any outstanding debt securities affected:


•	extending the fixed maturity;


•	reducing the principal amount, reducing the rate of or extending the time of payment of interest, or any premium payable upon redemption;


•	reducing the principal amount of discount securities payable upon acceleration of maturity;


•	making the principal of or premium or interest payable in currency other than that stated;


•	impairing the right to institute suit for the enforcement of any payment on or after the fixed maturity date;


•	materially adversely affecting the economic terms of any right to convert or exchange; and


•	reducing the percentage of debt securities, the holders of which are required to consent to any amendment or waiver; or modifying, without the written consent of the trustee, the rights, duties or immunities of the trustee.

Except for certain specified provisions, and except as we may otherwise provide in the applicable prospectus supplement, the holders of at least a majority in principal amount of any series (or, at a meeting of holders of such series at which a quorum is present, the holders of a majority in principal amount represented at such meeting) may, on behalf of the holders of all debt securities of that series, waive our compliance with provisions of the indenture.

The holders of a majority in principal amount of the outstanding debt securities of any series may, on behalf of all such holders, waive any past default under the indenture with respect to that series and its consequences, other than a default in the payment of the principal of, premium or any interest; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration.

Discharge . Except as we may otherwise provide in the applicable prospectus supplement, the indenture will provide that we can elect to be discharged from our obligations with respect to one or more series of debt securities. In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, the premium, if any, and interest on, the debt securities of the affected series on the dates payments are due.

Form, Exchange and Transfer . Except as we may otherwise provide in the applicable prospectus supplement, we will issue debt securities only in fully registered form without coupons and, unless we otherwise specify in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. Except as we may otherwise provide in the applicable prospectus supplement, the indenture will provide that we may issue debt securities in temporary or permanent global form and as book-entry securities that will be deposited with a depositary named by us and identified in a prospectus supplement with respect to that series.

Subject to the terms of the indenture and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities or the indenture, we will make no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

We will name in the applicable prospectus supplement the security registrar, and any transfer agent in addition to the security registrar, that we initially designate for any debt securities. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each place of payment for the debt securities of each series.

Except as we may otherwise provide in a prospectus supplement, if we elect to redeem the debt securities of any series, we will not be required to:


•	issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or


•	register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.

Information Concerning the Trustee . The trustee, other than during the occurrence and continuance of an event of default under the indenture, will undertake to perform only those duties as are specifically set forth in the indenture. Upon an event of default, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs. Subject to this provision, the trustee will be under no obligation to exercise any of the powers given it by the indenture at the request of any holder unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur.

Payment and Paying Agents . Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of interest on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.

Unless we otherwise indicate in the applicable prospectus supplement, we will pay principal of and any

premium and interest at the office of the trustee or, at the option of the Company, by check payable to the holder. Unless we otherwise indicate in a prospectus supplement, we will designate the corporate trust office of the trustee our sole paying agent for payments. We will name in the applicable prospectus supplement any other paying agents that we initially designate. We will maintain a paying agent in each place of payment.

All money we pay to a paying agent or the trustee for the payment of principal or any premium or interest which remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the security thereafter may look only to us for payment thereof.

Governing Law . The indenture and the debt securities will be governed and construed in accordance with the laws of the State of New York.

No Personal Liability of Directors, Officers, Employees and Stockholders . No incorporator, stockholder, employee, agent, officer, director or subsidiary of ours will have any liability for any obligations of ours or, due to the creation of any indebtedness under the debt securities, the indentures or supplemental indentures. The indenture will provide that all such liability is expressly waived and released as a condition of, and as consideration for, the execution of such indentures and the issuance of the debt securities.

DESCRIPTION OF DEPOSITARY SHARES

We may offer depositary shares representing fractional interests in shares of our preferred stock of any series. In connection with the issuance of any depositary shares, we will enter into a deposit agreement with a depositary. Depositary shares may be evidenced by depositary receipts issued pursuant to the related deposit agreement. Additional information regarding any depositary shares we may offer, the series of preferred stock represented by those depositary shares and the related deposit agreement will be set forth in the applicable prospectus supplement.

DESCRIPTION OF WARRANTS, OTHER RIGHTS AND UNITS

We may from time to time issue warrants or other rights, or Rights, in one or more series, for the purchase of shares of our common stock or preferred stock. We may issue Rights independently or together with such securities, and such Rights may be attached to or separate from them. Rights will be evidenced by a Rights certificate issued under one or more Rights agreements between us and a Rights agent which will act solely as our agent in connection with the Rights and will not have any obligation or relationship of agency or trust for or with any holders or beneficial owners of Rights.

We may issue securities in units, or Units, each consisting of two or more types of securities. For example, we might issue Units consisting of a combination of shares of our common stock and warrants to purchase shares of our common stock. If we issue Units, the applicable prospectus supplement will contain information with regard to each of the securities that is a component of the Units. In addition, the applicable prospectus supplement will describe the terms of any Units we issue. The forms of any certificates and agreements relating to such Units will be filed as exhibits to the registration statement of which this prospectus forms a part by amendment thereof or as exhibits to a Current Report on Form 8-K incorporated herein by reference.

The applicable prospectus supplement and such forms may add, update or change the terms and conditions of the Rights or Units described in this prospectus. You should read the prospectus supplements, Rights agreements and Rights certificates that contain the terms of the Rights in their entirety.

The particular terms of each issue of Rights or Units will be described in the applicable prospectus supplement, including, to the extent applicable:


•	the title of the Rights or Units;


•	any initial offering price;


•	the title, aggregate principal amount or number and terms of the securities purchasable upon exercise of the Rights;


•	the principal amount or number of securities purchasable upon exercise of each Right and the price at which that principal amount or number may be purchased upon exercise of each Right;


•	the currency or currency units in which any offering price and any exercise price are payable;


•	the title and terms of any related securities with which the Rights are issued and the number of the Rights issued with each security;


•	any date on and after which the Rights or Units and the related securities will be separately transferable;


•	any minimum or maximum number of Rights that may be exercised at any one time;


•	the date on which the right to exercise the Rights will commence and the date on which the right will expire;


•	a discussion of U.S. federal income tax, accounting or other considerations applicable to the Rights or Units;


•	whether the Rights represented by the Rights certificates, if applicable, will be issued in registered or bearer form and, if registered, where they may be transferred and registered;


•	any anti-dilution provisions of the Rights or Units;


•	any redemption or call provisions applicable to the Rights;


•	any provisions for changes to or adjustments in the exercise price of any Rights; and


•	any additional terms of the Rights or Units, including terms, procedures and limitations relating to exchange and exercise of the Rights or Units.

Rights certificates will be exchangeable for new Rights certificates of different denominations and, if in registered form, may be presented for registration of transfer, and Rights may be exercised, at the corporate trust office of the Rights agent or any other office indicated in the applicable prospectus supplement. Before the exercise of Rights, holders of Rights will not be entitled to payments of any dividends, principal, premium or interest on securities purchasable upon exercise of the Rights, to vote, consent or receive any notice as a holder of and in respect of any such securities or to enforce any covenants in any indenture, or to exercise any other rights whatsoever as a holder of securities purchasable upon exercise of the Rights.

PLAN OF DISTRIBUTION

We may sell the offered securities in and outside the United States (1) through underwriters or dealers, (2) directly to one or more purchasers, including to a limited number of institutional purchasers, to a single purchaser or to our affiliates and stockholders, (3) through one or more brokers or dealers; (4) through agents or (5) through a combination of any of these methods.

We may also sell directly to investors through subscription rights distributed to our stockholders on a pro rata basis. In connection with any distribution of subscription rights to stockholders, if all of the underlying securities are not subscribed for, we may sell the unsubscribed shares of our common stock directly to third parties or may engage the services of one or more underwriters, dealers or agents, including standby underwriters, to sell the unsubscribed securities to third parties.

If underwriters or dealers are used in the sale, the securities will be acquired by the underwriters or dealers for their own account and may be resold from time to time in one or more transactions, including:


•	in one or more transactions at a fixed price or prices, which may be changed from time to time;


•	in “at-the-market offerings,” within the meaning of Rule 415(a)(4) of the Securities Act, to or through a market maker or into an existing trading market, on an exchange or otherwise;


•	through a market maker or into an existing trading market on an exchange or otherwise;


•	at prices related to those prevailing market prices; or


•	at negotiated prices.

The applicable prospectus supplement will set forth the following information to the extent applicable:


•	the terms of the offering;


•	the names of any underwriters, dealers or agents and the amounts of securities underwritten or purchased by each of them;


•	the name or names of any managing underwriter or underwriters;


•	the purchase price of the securities;


•	any options under which underwriters may purchase additional securities from us;


•	the net proceeds from the sale of the securities;


•	any delayed delivery arrangements;


•	any underwriting discounts, commissions and other items constituting underwriters’ compensation;


•	any initial public offering price;


•	any discounts or concessions allowed or reallowed or paid to dealers;


•	any commissions paid to agents; and


•	any securities exchanges or markets on which the securities may be listed.

Sale through Underwriters or Dealers

If any securities are offered through underwriters, the underwriters will acquire the securities for their own account and may resell them from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer and sell securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless otherwise provided in the applicable prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions, and the underwriters will be obligated to purchase all of the offered securities if they purchase any of them. In connection with the sale of securities, underwriters may be deemed to have received compensation from us in the form of underwriting discounts or commissions and dealers may receive compensation from the underwriters in the form of discounts or concessions. The underwriters may change from time to time any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers.

In order to facilitate the offering of securities, the underwriters may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. Specifically, the underwriters may overallot in connection with the offering, creating a short position in the securities for their account. In addition, to cover overallotments or to stabilize the price of the shares, the underwriters may bid for, and purchase, shares in the open market. Finally, an underwriting syndicate may reclaim selling concessions allowed to an underwriter or a dealer for distributing the securities in the offering if the syndicate repurchases previously distributed shares in transactions to cover syndicate short positions, in stabilization transactions, or otherwise. Any of these activities may stabilize or maintain the market price of the offered securities above independent market levels. The underwriters are not required to engage in these activities, and may discontinue any of these activities at any time.

Some or all of the securities that we offer through this prospectus may be new issues of securities with no established trading market. Any underwriters to whom we sell securities for public offering and sale may make a market in those securities, but they will not be obligated to do so and they may discontinue any market making at any time without notice. Accordingly, we cannot assure you of the liquidity of, or continued trading markets for, any securities offered pursuant to this prospectus.

If any securities are offered through dealers, we will sell the securities to them as principals. They may then resell those securities to the public at varying prices determined by the dealers at the time of resale.

Direct Sales and Sales through Agents

We may sell the securities directly to purchasers. If the securities are sold directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of those securities, we will describe the terms of any such sales in the applicable prospectus supplement. We may also sell the securities through agents designated from time to time. Sales may be made by means of ordinary brokers’ transactions on the OTCQB ^® Market at market prices, in block transactions and such other transactions as agreed by us and any agent. In the applicable prospectus supplement, we will name any agent involved in the offer or sale of the offered securities, and we will describe any commissions payable to the agent. Unless otherwise provided in the applicable prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

At-the-Market Offerings

To the extent that we make sales through one or more underwriters or agents in at-the-market offerings, we will do so pursuant to the terms of a sales agency financing agreement or other at-the-market offering arrangement between us, on one hand, and the underwriters or agents, on the other. If we engage in at-the-market sales pursuant to any such agreement, we will issue and sell our securities through one or more underwriters or agents, which may act on an agency basis or a principal basis. During the term of any such agreement, we may sell securities on a daily basis in exchange transactions or otherwise as we agree with the underwriters or agents. Any such agreement will provide that any securities sold will be sold at prices related to the then prevailing market prices for our securities.

Therefore, exact figures regarding proceeds that will be raised or commissions to be paid cannot be determined at this time. Pursuant to the terms of the agreement, we may agree to sell, and the relevant underwriters or agents may agree to solicit offers to purchase blocks of our common stock or other securities. The terms of any such agreement will be set forth in more detail in the applicable prospectus supplement.

Remarketing Arrangements

Offered securities may also be offered and sold, if we so indicate in the applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to their terms, or otherwise, by one or more remarketing firms, acting as principals for their own accounts or as our agents. Any remarketing firm will be identified and the terms of its agreements, if any, with us and its compensation will be described in the applicable prospectus supplement. Remarketing firms may be deemed to be underwriters of the offered securities under the Securities Act.

Delayed Delivery Contracts

If we so indicate in the applicable prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers by certain institutions to purchase securities from us pursuant to contracts providing for payment and delivery on a specified future date. The applicable prospectus supplement will describe the conditions to those contracts and the commission payable for solicitation of those contracts.

General Information

We may have agreements with the agents, dealers, underwriters and remarketing firms to indemnify them against certain civil liabilities, including liabilities under the Securities Act, or to contribute with respect to payments that the agents, dealers or underwriters may be required to make. Agents, dealers, underwriters and remarketing firms may be customers of, engage in transactions with or perform services for us in the ordinary course of their businesses.

Each underwriter, dealer and agent participating in the distribution of any of the securities that are issuable in bearer form will agree that it will not offer, sell or deliver, directly or indirectly, securities in bearer form in the United States or to United States persons, other than qualifying financial institutions, during the restricted period, as defined in United States Treasury Regulations Section 1.163-5(c)(2)(i)(D)(7).

LEGAL MATTERS

Certain legal matters in connection with this offering will be passed upon for us by Goodwin Procter LLP, Redwood City, California. Any underwriters will also be advised about the validity of the securities and other legal matters by their own counsel, which will be named in the prospectus supplement .

EXPERTS

27,500,000 Shares

Exicure, Inc.

Common Stock

PROSPECTUS SUPPLEMENT

Sole Book-Running Manager

Guggenheim Securities

Lead Manager

Chardan



	Co-Managers
H.C. Wainwright & Co.		Ladenburg Thalmann

July 30, 2019