Filed Pursuant to Rule 424(b)(5)

Registration No. 333-256627

Prospectus Supplement

(to Prospectus dated June 11, 2021)

$20,000,000 and 161,681 Shares of Common Stock

This prospectus supplement relates to the issuance and sale of up to $20,000,000 of shares of our common stock, or Purchase Shares, that we may sell to Lincoln Park Capital Fund, LLC, or Lincoln Park, from time to time pursuant to the purchase agreement, dated as of June 25, 2021, or the Purchase Agreement, that we have entered into with Lincoln Park, 107,788 shares of our common stock being issued to Lincoln Park as commitment shares under the Purchase Agreement, and up to an additional 53,893 shares of our common stock that may be issued to Lincoln Park as commitment shares pro-rata when and if Lincoln Park purchases (at our discretion) the $20,000,000 aggregate commitment.

This prospectus supplement and the accompanying prospectus also cover the resale of these shares by Lincoln Park to the public. See “Lincoln Park Transaction” for a description of the Purchase Agreement and additional information regarding Lincoln Park. Lincoln Park is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act of 1933, as amended, or the Securities Act.

The purchase price for the Purchase Shares will be based upon formulas set forth in the Purchase Agreement depending on the type of purchase notice we submit to Lincoln Park from time to time. We will pay the expenses incurred in connection with the issuance of the shares of our common stock. See “Plan of Distribution.”

Our common stock is listed on The NASDAQ Capital Market under the symbol “MBRX.” On June 24, 2021, the last reported sale price of our common stock on The NASDAQ Capital Market was $3.85 per share.

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 passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus supplement is June 25, 2021

TABLE OF CONTENTS

About This Prospectus Supplement

This prospectus supplement and the accompanying prospectus relate to the offering of our common stock. You should read this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we may authorize for use in connection with this offering, in their entirety before making an investment decision. You should also read and consider the information in the documents to which we have referred you in the section of this prospectus supplement entitled “Where You Can Find More Information” and “Incorporation by Reference.” These documents contain important information that you should consider when making your investment decision.

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of the offering of the common stock and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into this prospectus supplement and the accompanying prospectus. The second part, the accompanying prospectus, including the documents incorporated by reference into the accompanying prospectus, provides more general information, some of which may not apply to this offering. Generally, when we refer to this prospectus, we are referring to the combined document consisting of this prospectus supplement and the accompanying prospectus. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or in any document incorporated by reference into the accompanying prospectus that was filed with the Securities and Exchange Commission, or SEC, before the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date, the statement in the document having the later date modifies or supersedes the earlier statement.

We are responsible for the information contained in, or incorporated by reference into, this prospectus supplement, the accompanying prospectus and in any free writing prospectus that we may authorize for use in connection with this offering. We have not authorized any other person to provide you with different information, and we take no responsibility for any other information that others may give you.

We are not making an offer to sell or soliciting an offer to buy our common stock in any jurisdiction in which an offer or solicitation is not authorized or in which the person making that offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer or solicitation.

You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, and in any free writing prospectus that we may authorize for use in connection with this offering, is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates.

Unless the context otherwise requires or as otherwise expressly stated, references in this prospectus to the terms the “Company,” “MBI,” “we,” “our” and “us” or other similar terms mean Moleculin Biotech, Inc., unless we state otherwise or the context indicates otherwise.

Summary

This summary highlights information contained elsewhere or incorporated by reference in this prospectus supplement and the accompanying prospectus. This summary does not contain all of the information that you should consider before deciding to invest in our common stock. You should read this entire prospectus supplement and the accompanying prospectus carefully, including the "Risk Factors" section contained in this prospectus supplement, our financial statements and the related notes thereto and the other documents incorporated by reference in this prospectus supplement and the accompanying prospectus.

Overview

We are a clinical stage pharmaceutical company focused on the treatment of highly resistant cancers and viruses. We have three core technologies, based substantially on discoveries made at M.D. Anderson Cancer Center (MD Anderson). These three core technologies are Annamycin, our WP1066 portfolio, and our WP1122 portfolio and include a total of six drug candidates, three of which have now shown human activity in clinical trials.

We consider Annamycin to be a "next generation" anthracycline, unlike any currently approved anthracyclines, as it is designed to avoid multidrug resistance mechanisms with little to no cardiotoxicity (the efficacy of all currently approved anthracyclines is limited by both multidrug resistance and cardiotoxicity). WP1066 is one of several Immune/Transcription Modulators, designed to stimulate the immune response to tumors by inhibiting the errant activity of Regulatory T-Cells (TRegs) while also inhibiting key oncogenic transcription factors, including p-STAT3 (phosphorylated signal transducer and activator of transcription 3), c-Myc (a cellular signal transducer named after a homologous avian virus called Myelocytomatosis) and HIF-1α (hypoxia inducible factor 1α). These transcription factors are widely sought targets that are believed to contribute to an increase in cell survival and proliferation, and the angiogenesis (coopting vasculature for blood supply), invasion, metastasis and inflammation associated with tumors. They may also play a role in the inability of immune checkpoint inhibitors to affect more resistant tumors. WP1220 is a close analog to WP1066 that we have developed as a potential topical therapy for skin-related diseases.

Our third core technology is centered on new compounds designed to target the roles of glycolysis and glycosylation in both cancer and viral diseases. As an example, 2-deoxy-D-glucose (2-DG) is a glucose decoy that is capable of inhibiting glycolysis, thereby cutting off the primary fuel supply for both cancer cells and viral host cells by taking advantage of their high level of dependence on glucose in comparison to healthy cells. In addition, 2-DG is capable of altering glycosylation, a process by which, when coopted by tumors, cancer cells are believed to evade the body’s immune response. In the case of viruses like SARS-CoV-2 (the virus responsible for COVID-19), glycosylation forms the glycoprotein spikes surrounding the coronavirus that give it its name and enable both evasion of the immune response and the ability to infect new host cells. One of the limitations of 2-DG, however, is how rapidly it is metabolized, resulting in a short circulation time and limited tissue/organ distribution characteristics. Our lead Metabolism/Glycosylation Inhibitor, WP1122, is a prodrug of 2-DG that appears to improve the drug-like properties of 2-DG by increasing its circulation time and improving tissue/organ distribution. Recent published research has identified that 2-DG has antiviral potential against SARS-CoV-2 in vitro and, based on publicly available information, a recently completed Phase 2 clinical trial by an unrelated company in India has reported efficacy in COVID-19 patients, resulting in the Emergency Use Authorization of 2-DG by the Drugs Controller General of India. New research also points to the potential for 2-DG to be capable of enhancing the usefulness of checkpoint inhibitors. Considering that WP1122 generally outperforms 2-DG alone in both in vitro and in vivo tumor models and in viral in vitro models, we believe WP1122 has the opportunity to become an important drug to potentiate existing therapies, including checkpoint inhibitors. We are also engaged in preclinical development of additional antimetabolites (WP1096 and WP1097) targeting glycolysis and glycosylation.

Recent Developments

On May 25, 2021, we announced that we had received clearance to initiate our Phase 1b/2 clinical trial evaluating Annamycin for the treatment of soft tissue sarcoma (STS) lung metastases. The Phase 1b/2 study is a multi-center, open-label, single-arm study that in Phase 1b will determine the maximum- tolerated dose (MTD) or the recommended Phase 2 dose (RP2D) and safety of Annamycin and in Phase 2 will explore the efficacy of Annamycin as a single agent for the treatment of subjects with STS with lung metastases for which chemotherapy is considered appropriate. A minimum of 3 subjects for each dosing cohort will be enrolled in the Phase 1b portion of the study until an MTD is identified. A maximum of 25 subjects will be enrolled at the RP2D to further evaluate efficacy. On June 21, 2021, we announced that we had commenced enrollment and dosed the first subject in its U.S. Phase 1b/2 clinical trial evaluating Annamycin for the treatment of STS.

Company Information

We were incorporated on July 28, 2015. Our principal executive office is located at 5300 Memorial Drive, Suite 950, Houston, Texas 77007. Our website address is www.moleculin.com. We do not incorporate by reference into this prospectus supplement the information on our website, and you should not consider it as part of this prospectus supplement. 

The Offering

The number of shares of our common stock outstanding after this offering is based on 28,444,675 shares of common stock outstanding as of June 24, 2021, and excludes:

●      2,833,284 shares of common stock issuable upon the exercise of a warrants at a weighted average exercise price of $9.76 per share;

●      1,436,352 shares of common stock issuable upon the exercise of options at a weighted average exercise price of $8.46 per share;

●      248,482 shares of common stock issuable upon the vesting of unvested restricted stock units; and

●      43,628 shares of common stock available for future issuance under the Moleculin Biotech, Inc. 2015 Stock Plan, as amended.

Unless otherwise indicated, all information in this prospectus supplement assumes no exercise of outstanding options or warrants described above.

Risk Factors

An investment in our securities involves risks. We urge you to consider carefully the risks described below, and in the documents incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment decision, including those risks identified under “Item 1A. Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2020, which is incorporated by reference in this prospectus supplement and which may be amended, supplemented or superseded from time to time by other reports that we subsequently file with the SEC. Additional risks, including those that relate to any particular securities we offer, may be included in a future prospectus supplement or free writing prospectus that we authorize from time to time, or that are incorporated by reference into this prospectus supplement or the accompanying prospectus in connection with this offering. If any of these risks actually occurs, our business, financial condition, results of operations or cash flow could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section below entitled “Special Note Regarding Forward-Looking Statements.”

Risks Related to this Offering

The sale or issuance of our common stock to Lincoln Park may cause dilution and the sale of the shares of common stock acquired by Lincoln Park, or the perception that such sales may occur, could cause the price of our common stock to fall.

On June 25, 2021, we entered into the Purchase Agreement with Lincoln Park, pursuant to which Lincoln Park has committed to purchase up to $20,000,000 of our common stock. Upon the execution of the Purchase Agreement, we issued 107,788 shares of common stock to Lincoln Park as an initial fee for its commitment to purchase shares of our common stock under the Purchase Agreement, and we agreed to issue Lincoln Park up to an additional 53,893 shares of our common stock as commitment shares pro-rata when and if Lincoln Park purchases (at our discretion) the $20,000,000 aggregate commitment. The remaining shares of our common stock that may be issued under the Purchase Agreement may be sold by us to Lincoln Park at our discretion from time to time over a 36-month period commencing after the satisfaction of certain conditions set forth in the Purchase Agreement, including that the SEC has declared effective the registration statement that includes this prospectus. The purchase price for the shares that we may sell to Lincoln Park under the Purchase Agreement will fluctuate based on the price of our common stock. Depending on market liquidity at the time, sales of such shares may cause the trading price of our common stock to fall.

We generally have the right to control the timing and amount of any future sales of our shares to Lincoln Park. Additional sales of our common stock, if any, to Lincoln Park will depend upon market conditions and other factors to be determined by us. We may ultimately decide to sell to Lincoln Park all, some or none of the additional shares of our common stock that may be available for us to sell pursuant to the Purchase Agreement. If and when we do sell shares to Lincoln Park, after Lincoln Park has acquired the shares, Lincoln Park may resell all, some or none of those shares at any time or from time to time in its discretion. Therefore, sales to Lincoln Park by us could result in substantial dilution to the interests of other holders of our common stock. Additionally, the sale of a substantial number of shares of our common stock to Lincoln Park, or the anticipation of such sales, could make it more difficult for us to sell equity or equity-related securities in the future at a time and at a price that we might otherwise wish to effect sales.

We may require additional financing to sustain our operations, without which we may not be able to continue operations, and the terms of subsequent financings may adversely impact our stockholders.

We may direct Lincoln Park to purchase up to $20,000,000 worth of shares of our common stock under our agreement over a 36-month period generally in amounts up to 75,000 shares of our common stock, which may be increased to up to 150,000 shares of our common stock depending on the market price of our common stock at the time of sale, and, in each case, subject to a maximum limit of $2,500,000 per purchase, on any single business day (such share amounts being subject to adjustment for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction as provided in the Purchase Agreement).

The extent we rely on Lincoln Park as a source of funding will depend on a number of factors including the prevailing market price of our common stock and the extent to which we are able to secure working capital from other sources. If obtaining sufficient funding from Lincoln Park were to prove unavailable or prohibitively dilutive, we will need to secure another source of funding in order to satisfy our working capital needs. Even if we sell all $20,000,000 under the Purchase Agreement to Lincoln Park, we may still need additional capital to finance our future production plans and working capital needs, and we may have to raise funds through the issuance of equity or debt securities. Depending on the type and the terms of any financing we pursue, stockholders’ rights and the value of their investment in our common stock could be reduced. A financing could involve one or more types of securities including common stock, convertible debt or warrants to acquire common stock. These securities could be issued at or below the then prevailing market price for our common stock. In addition, if we issue secured debt securities, the holders of the debt would have a claim to our assets that would be prior to the rights of stockholders until the debt is paid. Interest on these debt securities would increase costs and negatively impact operating results. If the issuance of new securities results in diminished rights to holders of our common stock, the market price of our common stock could be negatively impacted. Should the financing we require to sustain our working capital needs be unavailable or prohibitively expensive when we require it, the consequences could be a material adverse effect on our business, operating results, financial condition and prospects.

Our management will have broad discretion over the use of the net proceeds from our sale of shares of common stock to Lincoln Park, you may not agree with how we use the proceeds and the proceeds may not be invested successfully.

Our management will have broad discretion as to the use of the net proceeds from our sale of shares of common stock to Lincoln Park, and we could use them for purposes other than those contemplated at the time of commencement of this offering. Accordingly, you will be relying on the judgment of our management with regard to the use of those net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. It is possible that, pending their use, we may invest those net proceeds in a way that does not yield a favorable, or any, return for us. The failure of our management to use such funds effectively could have a material adverse effect on our business, financial condition, operating results and cash flows.

Special Note Regarding Forward-Looking Statements

This prospectus supplement, the accompanying prospectus and the other documents we have filed with the SEC that are incorporated herein by reference contain forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans, objectives of management or other financial items are forward-looking statements. The words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “plan,” “predict,” “project,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this prospectus supplement, particularly as set forth and incorporated by reference in the “Risk Factors” section above, that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures, collaborations or investments we may make. You should read this prospectus supplement, the accompanying prospectus and the documents that we incorporate by reference in this prospectus supplement completely and with the understanding that our actual future results may be materially different from what we expect. We do not assume any obligation to update any forward-looking statements, except as otherwise required by law. We advise you, however, to consult any further disclosures we make on related subjects in our future annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K we file with or furnish to the SEC.

Use of Proceeds

We may receive up to $20.0 million in aggregate gross proceeds under the Purchase Agreement from any sales we make to Lincoln Park pursuant to the Purchase Agreement after the date of this prospectus supplement. We may sell fewer than all of the shares offered by this prospectus supplement, in which case our offering proceeds will be less. Because we are not obligated to sell any shares of our common stock under the Purchase Agreement, the actual total offering amount and proceeds to us, if any, are not determinable at this time. See “Plan of Distribution” elsewhere in this prospectus supplement for more information.

We currently intend to use the net proceeds from this offering, if any, for clinical trials, preclinical programs, for other research and development activities and for general corporate purposes.

Dividend Policy

We have never declared or paid any cash dividends on our capital stock, and we do not currently intend to pay any cash dividends on our common stock for the foreseeable future. We expect to retain future earnings, if any, to fund the development and growth of our business. Any future determination to pay dividends on our common stock will be at the discretion of our board of directors and will depend upon, among other factors, our results of operations, financial condition, capital requirements and any contractual restrictions. 

Dilution

The sale of our common stock to Lincoln Park pursuant to the Purchase Agreement may have a dilutive impact on our stockholders. In addition, the lower our stock price is at the time we exercise our right to sell shares to Lincoln Park, the more shares of our common stock we will have to issue to Lincoln Park pursuant to the Purchase Agreement and our existing stockholders will experience greater dilution.

Our net tangible book value as of March 31, 2021 was approximately $77.4 million, or $2.72 per share of common stock. Net tangible book value per share is calculated by subtracting our total liabilities less the contingent consideration from our total tangible assets, which is total assets less intangible assets and goodwill, and dividing this amount by the number of shares of common stock outstanding.

After giving effect to the assumed sale by us of 5,194,805 shares of our common stock to Lincoln Park pursuant to the Purchase Agreement at an assumed average sale price of $3.85 per share of our common stock, which was the last reported sale price of our common stock on Nasdaq on June 24, 2021, and the placement of up to 161,681 shares of common stock to Lincoln Park as Commitment Shares and without giving effect to the Exchange Cap under the Purchase Agreement, and after deducting estimated aggregate offering expenses payable by us, our as adjusted net tangible book value as of March 31, 2021 would have been approximately $97.4 million, or $2.89 per share of common stock. This represents an immediate increase in net tangible book value per share of $0.17 to our existing stockholders.

The following table illustrates this per share dilution:

The above table and discussion is based on 28,444,425 shares of common stock outstanding as of March 31, 2021 and exclude the following, all, unless otherwise noted, as of March 31, 2021:

•          903,487 shares of common stock issuable upon the exercise of outstanding stock options, vested and unvested, with a weighted-average exercise price of $11.24 per share;

•          2,833,284 shares of common stock issuable upon the exercise of outstanding warrants with a weighted-average exercise price of $9.76 per share; and

•          up to an aggregate of 726,493 shares of common stock reserved for future issuance under our 2015 Stock Plan, as amended.

To the extent that options or warrants outstanding as of March 31, 2021 have been or are exercised, or other shares are issued, investors purchasing shares in this offering could experience further dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of these securities could result in further dilution to our stockholders.

Lincoln Park Transaction

General

On June 25, 2021, we entered into the Purchase Agreement with Lincoln Park. In connection with the Purchase Agreement, on June 25, 2021, we also entered into a registration rights agreement, or the Registration Rights Agreement, with Lincoln Park, pursuant to which we agreed to take specified actions to maintain the registration of the shares of our common stock subject to the offering described in this prospectus supplement and accompanying prospectus. Pursuant to the terms of the Purchase Agreement, Lincoln Park has agreed to purchase from us up to $20,000,000 of our common stock (subject to certain limitations) from time to time during the term of the Purchase Agreement. Pursuant to the terms of the Purchase Agreement and Registration Rights Agreement, we have filed with the SEC this prospectus supplement regarding the sale under the Securities Act of the shares issuable to Lincoln Park under the Purchase Agreement. Pursuant to the terms of the Purchase Agreement, on the date of this prospectus, we are issuing 107,788 shares of our common stock to Lincoln Park as commitment shares under the Purchase Agreement, and we have agreed to issue up to an additional 53,893 shares of our common stock to Lincoln Park as commitment shares pro-rata when and if Lincoln Park purchases (at our discretion) the $20,000,000 aggregate commitment.

We may, from time to time and at our sole discretion, direct Lincoln Park to purchase shares of our common stock upon the satisfaction of certain conditions set forth in the Purchase Agreement at a purchase price per share based on the market price of our common stock at the time of sale as computed under the Purchase Agreement. Lincoln Park may not assign or transfer its rights and obligations under the Purchase Agreement.

Under applicable rules of the Nasdaq Capital Market, in no event may we issue or sell to Lincoln Park under the Purchase Agreement shares of our common stock in excess of 5,686,041 shares (including the Commitment Shares), which represents 19.99% of the shares of our common stock outstanding immediately prior to the execution of the Purchase Agreement, or the Exchange Cap, unless (i) we obtain stockholder approval to issue shares of our common stock in excess of the Exchange Cap or (ii) the average price of all applicable sales of our common stock to Lincoln Park under the Purchase Agreement equals or exceeds $3.8412 per share (which represents the lower of (A) the official closing price of our common stock on Nasdaq on the date of the Purchase Agreement and (B) the average official closing price of our common stock on Nasdaq for the five consecutive trading days ending on the date of the Purchase Agreement, adjusted such that the transactions contemplated by the Purchase Agreement are exempt from the Exchange Cap limitation under applicable Nasdaq rules. In any event, the Purchase Agreement specifically provides that we may not issue or sell any shares of our common stock under the Purchase Agreement if such issuance or sale would breach any applicable rules or regulations of the Nasdaq Capital Market.

The Purchase Agreement also prohibits us from directing Lincoln Park to purchase any shares of our common stock if those shares, when aggregated with all other shares of our common stock then beneficially owned by Lincoln Park, would result in Lincoln Park and its affiliates exceeding the Beneficial Ownership Cap.

Purchase of Shares under the Purchase Agreement

Regular Purchases

Under the Purchase Agreement, on any business day selected by us, we may direct Lincoln Park to purchase up to 75,000 shares of our common stock on such business day (or the purchase date), which we refer to as a Regular Purchase, provided, however, that (i) a Regular Purchase may be increased to up to 100,000 shares, if the closing sale price of our common stock on Nasdaq is not below $4.00 on the applicable purchase date; and (ii) a Regular Purchase may be increased to up to 150,000 shares, if the closing sale price of our common stock on Nasdaq is not below $5.00 on the applicable purchase date. Lincoln Park’s committed under each Regular Purchase cannot exceed $2,500,000. In each case, upon the parties’ mutual agreement, the maximum amount of any single Regular Purchase may be increased. We may direct Lincoln Park to purchase shares in Regular Purchases as often as every business day. The foregoing share amounts and per share prices will be adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction occurring after the date of the Purchase Agreement.

The purchase price per share for each such Regular Purchase will be equal to the lesser of:

●     the lowest sale price for our common stock on Nasdaq during the purchase date of such shares; or

●     the average of the three lowest closing sale prices for our common stock on Nasdaq during the ten consecutive business days prior to the purchase date of such shares.

Accelerated Purchases

We also have the right to direct Lincoln Park, on any business day on which we have properly submitted to Lincoln Park a Regular Purchase notice for the maximum amount of shares we are then permitted to sell in a Regular Purchase, to purchase an additional amount of our common stock, which we refer to as an Accelerated Purchase, of up to the lesser of: 

●     300% of the number of shares to be purchased pursuant to such Regular Purchase; and

●     30% of the aggregate shares of our common stock traded on Nasdaq during the period on the trading day immediately following the purchase date for such Regular Purchase, which we refer to as the “Accelerated Purchase Date,” beginning at the commencement of regular trading on Nasdaq (or such later time on such Accelerated Purchase Date as mutually agreed by us and Lincoln Park specified in the Accelerated Purchase notice for such Accelerated Purchase), and ending at the close of regular trading on Nasdaq on such Accelerated Purchase Date, or, if certain trading volume or market price thresholds specified in the Purchase Agreement are crossed prior to the close of regular trading on Nasdaq on the applicable Accelerated Purchase Date, ending at such earlier time that any one of such thresholds is crossed, which period of time on the applicable Accelerated Purchase Date we refer to as the “Accelerated Purchase Measurement Period.”

The purchase price per share for each such Accelerated Purchase will be equal to 97% of the lesser of:

●     the volume-weighted average price of our common stock on Nasdaq during the applicable Accelerated Purchase Measurement Period on the applicable Accelerated Purchase date; and

●     the closing sale price of our common stock on the applicable Accelerated Purchase date.

The parties may mutually agree to increase the number of shares to be purchased by Lincoln Park pursuant to any Accelerated Purchase.

Additional Accelerated Purchases

We also have the right to direct Lincoln Park, prior to 1:00 p.m., Eastern time, on an Accelerated Purchase Date for an Accelerated Purchase for which the applicable Accelerated Purchase Measurement Period has theretofore ended and all of the shares subject thereto have been properly delivered to Lincoln Park, to purchase additional shares of our common stock in another Accelerated Purchase, which we refer to as an Additional Accelerated Purchase, on the same business day, which in reference to an Additional Accelerated Purchase we refer to as an Additional Accelerated Purchase Date, of up to the lesser of:

●     300% of the number of shares purchased pursuant to the applicable corresponding Regular Purchase; and

●     30% of the aggregate shares of our common stock traded on Nasdaq during the period on the applicable Additional Accelerated Purchase Date beginning at the time mutually agreed by us and Lincoln Park and specified in the Additional Accelerated Purchase notice for such Additional Accelerated Purchase, and ending at the close of regular trading on Nasdaq on such Additional Accelerated Purchase Date, or, if certain trading volume or market price thresholds specified in the Purchase Agreement are crossed prior to the close of regular trading on Nasdaq on such date, ending at such earlier time that any one of such thresholds is crossed, which period of time on the applicable Additional Accelerated Purchase Date we refer to as the “Additional Accelerated Purchase Measurement Period”.

We may, in our sole discretion, submit multiple Additional Accelerated Purchase notices to Lincoln Park on a single Additional Accelerated Purchase Date, provided that (i) such Additional Accelerated Purchase notice is received by Lincoln Park prior to 1:00 p.m., Eastern time, on such Additional Accelerated Purchase Date and (ii) all prior Accelerated Purchases and Additional Accelerated Purchases (including those that have occurred earlier on the same trading day) have been completed and all of the shares to be purchased thereunder have theretofore been properly delivered to Lincoln Park in accordance with the Purchase Agreement.

The purchase price per share for each such Additional Accelerated Purchase will be equal to 97% of the lower of:

●     the volume-weighted average price of our common stock on Nasdaq during the applicable Additional Accelerated Purchase Measurement Period on the applicable Additional Accelerated Purchase date; and

●     the closing sale price of our common stock on Nasdaq on the applicable Additional Accelerated Purchase date.

We and Lincoln Park may mutually agree to increase the number of shares to be purchased by Lincoln Park pursuant to any Additional Accelerated Purchase.

In the case of Regular Purchases, Accelerated Purchases and Additional Accelerated Purchases, the purchase price per share will be equitably adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction occurring during the business days used to compute the purchase price.

Other than as described above, there are no trading volume requirements or restrictions under the Purchase Agreement, and we will control the timing and amount of any sales of our common stock to Lincoln Park.

Events of Default

Events of default under the Purchase Agreement include the following:

●     the effectiveness of the registration statement of which this prospectus supplement and accompanying prospectus form a part lapses for any reason (including, without limitation, the issuance of a stop order by the SEC), or any required prospectus supplement and accompanying prospectus are unavailable for the resale by Lincoln Park of our common stock offered hereby, and such lapse or unavailability continues for a period of 10 consecutive business days or for more than an aggregate of 30 business days in any 365-day period;

●     suspension by the principal market of our common stock from trading or failure of the common stock to be listed on the Nasdaq for a period of one business day;

●     the de-listing of our common stock from the Nasdaq Capital Market, our principal market, unless our common stock is immediately thereafter trading on the Nasdaq Global Select Market, the Nasdaq Global Market, the New York Stock Exchange, the NYSE American, the NYSE Arca, the OTC Bulletin Board or the OTC Markets (or any other comparable market) a nationally recognized successor to any of the foregoing);

●     the failure for any reason by our transfer agent to issue Purchase Shares to Lincoln Park within two business days after any purchase date, Accelerated Purchase date or Additional Accelerated Purchase date, as applicable, on which Lincoln Park is entitled to receive such Purchase Shares;

●     any breach of the representations, warranties, covenants or other terms or conditions contained in the Purchase Agreement or Registration Rights Agreement that has or could have a Material Adverse Effect (as defined in the Purchase Agreement) and, in the case of a breach of a covenant that is reasonably curable, that is not cured within a period of at least five business days;

●     our common stock ceases to be DTC authorized and ceases to participate in the DWAC/FAST systems or if we fail to maintain the service of our transfer agent (or a successor transfer agent) with respect to the issuance of Purchase Shares under the Purchase Agreement;

●     if at any time the Exchange Cap (to the extent applicable under the terms of the Purchase Agreement) is reached and our stockholders have not approved the issuance of common stock in excess of the Exchange Cap in accordance with the applicable rules of the Nasdaq Capital Market; or

●     any voluntary or involuntary participation or threatened participation in insolvency or bankruptcy proceedings by or against us.

Lincoln Park does not have the right to terminate the Purchase Agreement upon any of the events of default set forth above, however, the Purchase Agreement will automatically terminate upon initiation of insolvency or bankruptcy proceedings by or against us. During an event of default, all of which are outside of Lincoln Park’s control, we are not permitted to direct Lincoln Park to purchase any shares of our common stock under the Purchase Agreement.

Our Termination Rights

We have the unconditional right, at any time, for any reason and without any payment or liability to us, to give one business day notice to Lincoln Park to terminate the Purchase Agreement.

No Short-Selling or Hedging by Lincoln Park

Lincoln Park has agreed that neither it nor any of its affiliates shall engage in any direct or indirect short-selling or hedging of our common stock during any time prior to the termination of the Purchase Agreement.

Prohibitions on Variable Rate Transactions

Subject to specified exceptions included in the Purchase Agreement, we are limited in our ability to enter into specified variable rate transactions until the earliest of: (i) the nine-month anniversary of the termination of the Purchase Agreement, and (ii) the later of (A) the thirty-six month anniversary of the date of this prospectus supplement, and (B) the thirty-six month anniversary of the commencement date of the Purchase Agreement. Such transactions include, among others, the issuance of convertible securities with a conversion or exercise price that is based upon or varies with the trading price of our common stock after the date of issuance, the issuance of securities with embedded anti-dilution provisions, the issuance of securities with an embedded put or call right or at a price subject to being reset after the initial issuance contingent on our business or market performance or entry into any new “equity line of credit.”

Effect of Performance of the Purchase Agreement on our Stockholders

All shares registered in this offering that have been or may be issued or sold by us to Lincoln Park under the Purchase Agreement are expected to be freely tradable. Shares registered in this offering may be sold over a period of up to 36 months commencing on the date of this prospectus supplement. The sale by Lincoln Park of a significant amount of shares registered in this offering at any given time could cause the market price of our common stock to decline and to be highly volatile. Sales of our common stock to Lincoln Park, if any, will depend upon market conditions and other factors to be determined by us, in our sole discretion. We may ultimately decide to sell to Lincoln Park all, some or none of the additional shares of our common stock that may be available for us to sell pursuant to the Purchase Agreement. If and when we do sell shares to Lincoln Park, after Lincoln Park has acquired the shares, Lincoln Park may resell all, some or none of those shares at any time or from time to time in its discretion. Therefore, sales to Lincoln Park by us under the Purchase Agreement may result in substantial dilution to the interests of other holders of our common stock. In addition, if we sell a substantial number of shares to Lincoln Park under the Purchase Agreement, or if investors expect that we will do so, the actual sales of shares or the mere existence of our arrangement with Lincoln Park may make it more difficult for us to sell equity or equity-related securities in the future at a time and at a price that we might otherwise wish to effect such sales. However, we have the right to control the timing and amount of any additional sales of our shares to Lincoln Park and the Purchase Agreement may be terminated by us at any time at our discretion without any cost to us.

Pursuant to the terms of the Purchase Agreement, we have the right, but not the obligation, to direct Lincoln Park to purchase up to $20,000,000 of our common stock, exclusive of the Commitment Shares being issued to Lincoln Park as consideration for its commitment to purchase shares of our common stock under the Purchase Agreement. The Purchase Agreement prohibits us from issuing or selling to Lincoln Park under the Purchase Agreement (i) shares of our common stock in excess of the Exchange Cap, unless we obtain stockholder approval to issue shares in excess of the Exchange Cap or the average price of all applicable sales of our common stock to Lincoln Park under the Purchase Agreement equals or exceeds $3.8412 per share, such that the transactions contemplated by the Purchase Agreement are exempt from the Exchange Cap limitation under applicable Nasdaq rules and (ii) any shares of our common stock if those shares, when aggregated with all other shares of our common stock then beneficially owned by Lincoln Park, would exceed the Beneficial Ownership Cap.

The following table sets forth the amount of gross proceeds we would receive from Lincoln Park from our sale of shares to Lincoln Park under the Purchase Agreement at varying purchase prices:

(1)     Includes the total number of Purchase Shares that we would have sold under the Purchase Agreement at the corresponding assumed average purchase price set forth in the first column, up to the aggregate purchase price of $20,000,000, if available, while giving effect to the Exchange Cap and without regard for the Beneficial Ownership Cap, and excludes the Commitment Shares.

(2)     The denominator is based on 28,444,425 shares outstanding as of June 24, 2021 adjusted to include the issuance of (i) 107,788 Commitment Shares being issued to Lincoln Park as consideration for its commitment to purchase shares of our common stock under the Purchase Agreement plus the number of additional Commitment Shares that would be issuable to Lincoln Park if it purchases the amount of shares set forth in the table and (ii) the number of shares set forth in the adjacent column that we would have sold to Lincoln Park, assuming the average purchase price in the first column. The numerator is based on the number of shares issuable under the Purchase Agreement (that are the subject of this offering) at the corresponding assumed average purchase price set forth in the first column.

(3)     The closing sale price of our common stock on Nasdaq on June 24, 2021.

Plan of Distribution

Pursuant to this prospectus supplement and the accompanying prospectus, we are offering up to $20.0 million in shares of our common stock and 107,788 shares of our common stock are being issued to Lincoln Park as commitment shares under the Purchase Agreement, and we have agreed to issue up to an additional 53,893 shares of our common stock to Lincoln Park as commitment shares pro-rata when and if Lincoln Park purchases (at our discretion) the $20,000,000 aggregate commitment. This prospectus supplement and the accompanying prospectus also cover the resale of these shares by Lincoln Park to the public.

We may, from time to time and at our sole discretion, direct Lincoln Park to purchase shares of our common stock in amounts up to 75,000 shares on any single business day from and after the date of this prospectus supplement, which amounts may be increased to up to 150,000 shares of our common stock depending on the market price of our common stock at the time of sale, subject to further increases upon the parties mutual agreement, which share amounts and related market prices will be adjusted for any reorganization, recapitalization, non-cash dividend, stock split, reverse stock split or other similar transaction occurring after the date of the Purchase Agreement. In addition, upon notice to Lincoln Park, we may, from time to time and at our sole discretion, direct Lincoln Park to purchase additional shares of our common stock in “accelerated purchases,” and/or “additional accelerated purchases” as set forth in the Purchase Agreement. The purchase price per share is based on the market price of our common stock at the time of sale as computed under the Purchase Agreement. Lincoln Park may not assign or transfer its rights and obligations under the Purchase Agreement. See “Lincoln Park Transaction-Purchases of Shares under the Purchase Agreement.”

Lincoln Park is an “underwriter” within the meaning of Section 2(a)(11) of the Securities Act.

We have agreed to indemnify Lincoln Park and certain other persons against certain liabilities in connection with the offering of shares of our common stock offered. We have agreed to reimburse Lincoln Park for certain of its expenses in connection with the offering.

Lincoln Park has represented to us that at no time prior to the Purchase Agreement has Lincoln Park or its agents, representatives or affiliates engaged in or effected, in any manner whatsoever, directly or indirectly, any short sale (as such term is defined in Rule 200 of Regulation SHO of the Exchange Act) of our common stock or any hedging transaction, which establishes a net short position with respect to our common stock. Lincoln Park agreed that during the term of the Purchase Agreement, it, its agents, representatives or affiliates will not enter into or effect, directly or indirectly, any of the foregoing transactions.

We have advised Lincoln Park that it is required to comply with Regulation M promulgated under the Exchange Act. With certain exceptions, Regulation M precludes Lincoln Park, any affiliated purchasers, and any broker-dealer or other person who participates in the distribution from bidding for or purchasing, or attempting to induce any person to bid for or purchase any security which is the subject of the distribution until the entire distribution is complete. Regulation M also prohibits any bids or purchases made in order to stabilize the price of a security in connection with the distribution of that security. All of the foregoing may affect the marketability of the securities offered by this prospectus supplement.

This offering will terminate on the date that all shares offered by this prospectus supplement have been sold to Lincoln Park.

Our common stock is listed on the Nasdaq Capital Market under the symbol “MBRX.” Our transfer agent is VStock Transfer, LLC.

Legal Matters

The validity of the common stock offered hereby will be passed upon for us by Schiff Hardin LLP, Washington, DC. Lincoln Park is being represented by Dorsey & Whitney LLP, New York, New York.

Experts

The audited financial statements of Moleculin Biotech, Inc. as of December 31, 2020 and 2019, and for the years then ended, incorporated by reference in this prospectus and elsewhere in the registration statement have been incorporated by reference in reliance upon the report of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

Where You Can Find More Information

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 we filed with the SEC under the Securities Act and do not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus supplement or the accompanying prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you should refer to the exhibits that are a part of the registration statement or the exhibits to the reports or other documents incorporated by reference into this prospectus supplement or the accompanying prospectus for a copy of such contract, agreement or other document. 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. You may read and copy information filed by us with the SEC at the SEC’s public reference section, 100 F Street, N.E., Washington, D.C. 20549. Information regarding the operation of the public reference section can be obtained by calling 1-800-SEC-0330. The SEC also maintains an Internet site at http://www.sec.gov that contains reports, statements and other information about issuers, such as us, who file electronically with the SEC.

Incorporation by Reference

The SEC allows us to “incorporate by reference” into this prospectus supplement the information in other documents that we file with it. This means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be a part of this prospectus supplement, and information in documents that we file later with the SEC will automatically update and supersede information contained in documents filed earlier with the SEC or contained in this prospectus supplement. We incorporate by reference in this prospectus supplement the documents listed below and any future filings that we may make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act prior to the termination of the offering under this prospectus supplement; provided, however, that we are not incorporating, in each case, any documents or information deemed to have been furnished and not filed in accordance with SEC rules:

All reports and other documents we subsequently file pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the termination of this offering, including all such documents we may file with the SEC after the date of this prospectus supplement and accompanying prospectus, but excluding any information furnished to, rather than filed with, the SEC, will also be incorporated by reference into this prospectus supplement and deemed to be part of this prospectus supplement from the date of the filing of such reports and documents.

You may obtain a copy of any or all of the documents referred to above, which may have been or may be incorporated by reference into this prospectus supplement, including exhibits, at no cost to you by writing or telephoning us at the following address: Attention: Corporate Secretary, 5300 Memorial Drive, Suite 950, Houston, Texas 77007, telephone (713) 300-5160.

PROSPECTUS

$200,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

We may from time to time issue up to $200,000,000 aggregate dollar amount of common stock, preferred stock, debt securities, warrants or units of securities. We will specify in the accompanying prospectus supplement the terms of the securities to be offered and sold. We may sell these securities directly to you, through underwriters, dealers or agents we select, or through a combination of these methods. We will describe the plan of distribution for any particular offering of these securities in the applicable prospectus supplement. This prospectus may not be used to sell our securities unless it is accompanied by a prospectus supplement.

Our common stock is listed on The NASDAQ Capital Market and traded under the symbol "MBRX". On May 27, 2021, the closing price of the common stock, as reported on NASDAQ was $3.65 per share.

Investing in our securities is highly speculative and involves a high degree of risk. You should purchase these securities only if you can afford a complete loss of your investment. You should carefully consider the risks and uncertainties described under the heading "Risk Factors" beginning on page 3 of this prospectus before making a decision to purchase our securities.

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

The date of this prospectus is June 11, 2021.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, utilizing a "shelf" registration process. Under this shelf registration process, we may sell the securities described in this prospectus in one or more offerings up to a total dollar amount of $200,000,000.

We have provided to you in this prospectus a general description of the securities we may offer. Each time we sell securities under this shelf registration process, we will provide a prospectus supplement that will contain specific information about the terms of that offering. That prospectus supplement may include additional risk factors or other special considerations applicable to the securities being offered. We may also add, update or change in the prospectus supplement any of the information contained in this prospectus. To the extent there is a conflict between the information contained in this prospectus and the prospectus supplement, you should rely on the information in the prospectus supplement, provided that if a statement in any document is inconsistent with a statement in another document having a later date - for example, a document incorporated by reference in this prospectus or any prospectus supplement - the statement in the document having the later date modifies or supersedes the earlier statement. You should read both this prospectus and the prospectus supplement together with the additional information described under "Where You Can Find More Information."

The registration statement containing this prospectus, including the exhibits to the registration statement, provides additional information about us and the securities offered under this prospectus. The registration statement, including the exhibits, can be read at the SEC website or at the SEC offices mentioned under the heading "Where You Can Find More Information."

You should rely only on the information incorporated by reference or provided in this prospectus and the accompanying prospectus supplement. We have not authorized anyone to provide you with different information. We are not making an offer to sell or soliciting an offer to buy these securities in any jurisdiction in which the offer or solicitation is not authorized or in which the person making the offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make the offer or solicitation. You should not assume that the information in this prospectus or the accompanying prospectus supplement is accurate as of any date other than the date on the front of the document.

Unless the context requires otherwise, references to the "Company, " "we," "our," and "us," refer to Moleculin Biotech, Inc. and its subsidiaries, except that such terms refer to only Moleculin Biotech, Inc. and not its subsidiaries in the sections entitled "Description of Common Stock," "Description of Preferred Stock," "Description of Warrants," "Description of the Debt Securities," and "Description of the Stock Purchase Contracts and Stock Purchase Units."

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 under the Securities Act with respect to the securities offered in this offering. We file annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission. You may read and copy the registration statement and any other documents we have filed at the Securities and Exchange Commission’s Public Reference Room 100 F Street, N.E., Washington, D.C. 20549. Please call the Securities and Exchange Commission at 1-800-SEC-0330 for further information on the Public Reference Room. Our Securities and Exchange Commission filings are also available to the public at the Securities and Exchange Commission’s Internet site at www.sec.gov.

This prospectus is part of the registration statement and does not contain all of the information included in the registration statement. Whenever a reference is made in this prospectus to any of our contracts or other documents, the reference may not be complete and, for a copy of the contract or document, you should refer to the exhibits that are a part of the registration statement.

INCORPORATION BY REFERENCE

The SEC allows us to "incorporate by reference" into this prospectus the information we file with it, which means that we can disclose important information to you by referring you to those documents. Later information filed with the SEC will update and supersede this information.

We incorporate by reference the documents listed below, all filings filed by us pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of the initial registration statement of which this prospectus forms a part prior to effectiveness of such registration statement, and any future filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act prior to the time that all securities covered by this prospectus have been sold or the offering is otherwise terminated; provided, however, that we are not incorporating any information furnished under either Item 2.02 or Item 7.01 of any current report on Form 8-K:

An updated description of our capital stock is included in this prospectus under "Description of Common Stock" and "Description of Preferred Stock".

We will provide to each person, including any beneficial owner, to whom this prospectus is delivered, upon written or oral request, at no cost to the requester, a copy of any and all of the information that is incorporated by reference in this prospectus. You may request a copy of these filings, at no cost, by contacting us at:

Moleculin Biotech, Inc.

Attn: Corporate Secretary

5300 Memorial Drive, Suite 950

Houston, TX 77007

Phone: 713-300-5160

ABOUT MOLECULIN BIOTECH, INC.

Our Company

We are a clinical stage pharmaceutical company focused on the treatment of highly resistant cancers and viruses. We have three core technologies, based substantially on discoveries made at M.D. Anderson Cancer Center (MD Anderson). These three core technologies are Annamycin, the WP1066 Portfolio, and the WP1122 Portfolio and include a total of six drug candidates, three of which have now shown human activity in clinical trials.

We consider Annamycin to be a "next generation" anthracycline, unlike any currently approved anthracyclines, as it is designed to avoid multidrug resistance mechanisms with little to no cardiotoxicity (the efficacy of all currently approved anthracyclines is limited by both multidrug resistance and cardiotoxicity). WP1066 is one of several Immune/Transcription Modulators, designed to stimulate the immune response to tumors by inhibiting the errant activity of Regulatory T-Cells (TRegs) while also inhibiting key oncogenic transcription factors, including p-STAT3 (phosphorylated signal transducer and activator of transcription 3), c-Myc (a cellular signal transducer named after a homologous avian virus called Myelocytomatosis) and HIF-1α (hypoxia inducible factor 1α). These transcription factors are widely sought targets that are believed to contribute to an increase in cell survival and proliferation, and the angiogenesis (coopting vasculature for blood supply), invasion, metastasis and inflammation associated with tumors. They may also play a role in the inability of immune checkpoint inhibitors to affect more resistant tumors. WP1220 is a close analog to WP1066 that we have developed as a potential topical therapy for skin-related diseases.

Our third core technology is centered on new compounds designed to target the roles of glycolysis and glycosylation in both cancer and viral diseases. As an example, 2-deoxy-D-glucose (2-DG) is a glucose decoy that is capable of inhibiting glycolysis, thereby cutting off the primary fuel supply for both cancer cells and viral host cells by taking advantage of their high level of dependence on glucose in comparison to healthy cells. In addition, 2-DG is capable of altering glycosylation, a process by which, when coopted by tumors, cancer cells are believed to evade the body’s immune response. In the case of viruses like SARS-CoV-2 (the virus responsible for COVID-19), glycosylation forms the glycoprotein spikes surrounding the coronavirus that give it its name and enable both evasion of the immune response and the ability to infect new host cells. One of the limitations of 2-DG, however, is how rapidly it is metabolized, resulting in a short circulation time and limited tissue/organ distribution characteristics. Our lead Metabolism/Glycosylation Inhibitor, WP1122, is a prodrug of 2-DG that appears to improve the drug-like properties of 2-DG by increasing its circulation time and improving tissue/organ distribution. Recent published research has identified that 2-DG has antiviral potential against SARS-CoV-2 in vitro and, based on publicly available information, a recently completed Phase 2 clinical trial by an unrelated company in India has reported efficacy in COVID-19 patients, resulting in the Emergency Use Authorization of 2-DG by the Drugs Controller General of India. New research also points to the potential for 2-DG to be capable of enhancing the usefulness of checkpoint inhibitors. Considering that WP1122 generally outperforms 2-DG alone in both in vitro and in vivo tumor models and in viral in vitro models, we believe WP1122 has the opportunity to become an important drug to potentiate existing therapies, including checkpoint inhibitors. We are also engaged in preclinical development of additional antimetabolites (WP1096 and WP1097) targeting glycolysis and glycosylation.

Corporate Information

Our principal executive office is located at 5300 Memorial Drive, Suite 950, Houston, Texas 77007. Our website address is www.moleculin.com. Information contained in, or accessible through, our website does not constitute part of this prospectus and inclusions of our website address in this prospectus are inactive textual references only.

RISK FACTORS

Before making an investment decision, you should consider the "Risk Factors" included under Item 1A. of our most recent Annual Report on Form 10-K and in our updates to those Risk Factors in our Quarterly Reports on Form 10-Q, all of which are incorporated by reference in this prospectus, as updated by our future filings with the SEC. The market or trading price of our common stock could decline due to any of these risks. In addition, please read "Forward-Looking Statements" in this prospectus, where we describe additional uncertainties associated with our business and the forward-looking statements included or incorporated by reference in this prospectus. Please note that additional risks not currently known to us or that we currently deem immaterial may also impair our business and operations. The accompanying prospectus supplement may contain a discussion of additional risks applicable to an investment in us and the particular type of securities we are offering under that prospectus supplement.

FORWARD-LOOKING STATEMENTS

Some of the information in this prospectus, and the documents we incorporate by reference, contain forward-looking statements within the meaning of the federal securities laws. You should not rely on forward-looking statements in this prospectus, and the documents we incorporate by reference. Forward-looking statements typically are identified by use of terms such as "anticipate," "believe," "plan," "expect," "future," "intend," "may," "will," "should," "estimate," "predict," "potential," "continue," and similar words, although some forward-looking statements are expressed differently. This prospectus, and the documents we incorporate by reference, may also contain forward-looking statements attributed to third parties relating to their estimates regarding the markets we may enter in the future. All forward-looking statements address matters that involve risk and uncertainties, and there are many important risks, uncertainties and other factors that could cause our actual results to differ materially from the forward-looking statements contained in this prospectus, and the documents we incorporate by reference.

You should also consider carefully the statements under "Risk Factors" and other sections of this prospectus, and the documents we incorporate by reference, which address additional facts that could cause our actual results to differ from those set forth in the forward-looking statements. We caution investors not to place significant reliance on the forward-looking statements contained in this prospectus, and the documents we incorporate by reference. We undertake no obligation to publicly update or review any forward-looking statements, whether as a result of new information, future developments or otherwise.

USE OF PROCEEDS

We expect to use the net proceeds from the sale of securities offered by this prospectus and the prospectus supplement for our clinical trials, if any, and preclinical programs, for other research and development activities and for general corporate purposes. These may include additions to working capital, repayment of existing indebtedness and acquisitions. If we decide to use the net proceeds of any offering of securities other than for our clinical trials, if any, and preclinical programs, for other research and development activities and for general corporate purposes, we will describe the use of the net proceeds in the prospectus supplement for that offering.

DESCRIPTION OF COMMON STOCK

General

We are currently authorized to issue 100,000,000 shares of common stock, par value $0.001.

Subject to preferences that may be applicable to any preferred stock outstanding at the time, the holders of our common stock are entitled to receive dividends out of legally available assets at such times and in such amounts as our Board of Directors may from time to time determine. Each stockholder is entitled to one vote for each share of common stock held on all matters submitted to a vote of stockholders. Cumulative voting is not allowed.

Our common stock is not subject to conversion or redemption and holders of our common stock are not entitled to preemptive rights. Upon the liquidation, dissolution or winding up of our company, the remaining assets legally available for distribution to stockholders, after payment of claims or creditors and payment of liquidation preferences, if any, on outstanding preferred stock, are distributable ratably among the holders of our common stock and any participating preferred stock outstanding at that time. Each outstanding share of common stock is fully paid and nonassessable.

Anti-Takeover Effects of Provisions of Delaware Law and our Charter Documents

Provisions of Delaware law and our Amended and Restated Certificate of Incorporation ("Certificate of Incorporation") and our Amended and Restated Bylaws ("Bylaws") could make the acquisition of our company through a tender offer, a proxy contest or other means more difficult and could make the removal of incumbent officers and directors more difficult. We expect these provisions to discourage coercive takeover practices and inadequate takeover bids and to encourage persons seeking to acquire control of our company to first negotiate with our Board of Directors. We believe that the benefits provided by our ability to negotiate with the proponent of an unfriendly or unsolicited proposal outweigh the disadvantages of discouraging these proposals. We believe the negotiation of an unfriendly or unsolicited proposal could result in an improvement of its terms.

Our Bylaws do not permit stockholders to call a special meeting of stockholders. Our Bylaws provide that special meetings of the stockholders may be called by the Chairman of the Board of Directors, our Chief Executive Officer, our President, the Board of Directors, or in their absence or disability, by any vice president. Our Bylaws require that all stockholder actions be taken by a vote of the stockholders at an annual or special meeting, and do not permit our stockholders to act by written consent without a meeting. Our Bylaws provide for 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 the Board of Directors. At an annual meeting, stockholders may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of the Board of Directors. The 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 the stockholders. However, our Bylaws may have the effect of precluding the conduct of 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.

Exclusive Forum Provision.

Our certificate of incorporation provides that the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for (i) any derivative action or proceeding brought our behalf, (ii) any action asserting a claim of breach of a fiduciary duty owed by any of our directors or officers to us or our stockholders, (iii) any action asserting a claim against us arising pursuant to any provision of the Delaware General Corporation Law, or our certificate of incorporation or the bylaws, and (iv) any action asserting a claim against us governed by the internal affairs doctrine. This provision would not apply to suits brought to enforce a duty or liability created by the Exchange Act or Securities Act.

This choice of 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 such lawsuits against us and our directors, officers and employees. In addition, these provisions could increase the costs to stockholders in bringing such claims. Alternatively, a court could find these provisions of our certificate of incorporation to be inapplicable or unenforceable in respect of one or more of the specified types of actions or proceedings, which may require us to incur additional costs associated with resolving such matters in other jurisdictions, which could adversely affect our business and financial condition.

Quotation

Our common stock is listed on The NASDAQ Capital Market and traded under the symbol "MBRX".

Transfer Agent

The transfer agent for our common stock is VStock Transfer, LLC located at 18 Lafayette Place, Woodmere, New York 11598.

DESCRIPTION OF PREFERRED STOCK

General

We are currently authorized to issue 5,000,000 shares of preferred stock, par value $0.001. As of the date of this prospectus, we have no shares of preferred stock outstanding.

Our Board of Directors has the authority, without action by our stockholders, to designate and issue preferred stock in one or more series. Our Board of Directors may also designate the rights, preferences and privileges of each series of preferred stock, any or all of which may be greater than the rights of the common stock. It is not possible to state the actual effect of the issuance of any shares of preferred stock on the rights of holders of the common stock until our Board of Directors determines the specific rights of the holders of the preferred stock. However, these effects might include: (a) restricting dividends on the common stock; (b) diluting the voting power of the common stock; (c) impairing the liquidation rights of the common stock; and (d) delaying or preventing a change in control of our company without further action by our stockholders.

DESCRIPTION OF DEBT SECURITIES

General

The following description sets forth general terms that will apply to the debt securities. We will describe the particular terms of any debt securities that we offer in the prospectus supplement relating to those debt securities.

The debt securities will be either our senior debt securities or our subordinated debt securities. The senior debt securities will be issued under an indenture between us and the trustee named in the indenture. We refer to this indenture as the "senior indenture." The subordinated debt securities will be issued under a separate Subordinated Indenture between us and the trustee named in the indenture. We refer to this indenture as the "subordinated indenture" and, together with the senior indenture, as the "indentures." Except as permitted by applicable law, the indentures have been or will be qualified under the Trust Indenture Act of 1939.

We have filed the forms of the indentures as exhibits to the registration statement. For your convenience, we have included references to specific sections of the indentures in the descriptions below. Capitalized terms not otherwise defined in this prospectus will have the meanings given in the indenture to which they relate.

The following summaries of provisions of the debt securities and the indentures are not complete and are qualified in their entirety by reference to the provisions of the indentures and the debt securities.

Neither of the indentures limits the principal amount of debt securities that we may issue. Each indenture provides that debt securities may be issued in one or more series up to the principal amount that we may authorize from time to time. Each indenture also provides that the debt securities may be denominated in any currency or currency unit that we designate. In addition, each series of debt securities may be reopened in order to issue additional debt securities of that series in the future without the consent of the holders of debt securities of that series. Unless otherwise described in the prospectus supplement relating to a particular offering, neither the indentures nor the debt securities will contain any provisions to afford holders of any debt securities protection in the event of a takeover, recapitalization or similar restructuring of our business.

Unless otherwise described in the prospectus supplement relating to a particular offering, the senior debt securities will rank equally with all of our other unsecured and unsubordinated debt. The subordinated debt securities will be subordinated to the prior payment in full of our senior debt securities. We will describe the particular terms of the subordinated debt securities that we offer in the prospectus supplement relating to those subordinated debt securities.

We will describe the specific terms relating to each particular series of debt securities in the prospectus supplement relating to the offering of those debt securities. The terms we will describe in the prospectus supplement will include some or all of the following:

We may issue debt securities as original issue discount securities to be sold at a substantial discount below their principal amount. If we issue original issue discount securities, then we will describe the material U.S. federal income tax consequences that apply to those debt securities in the applicable prospectus supplement.

Registration and Transfer

We presently plan to issue each series of debt securities only as registered securities. However, we may issue a series of debt securities as bearer securities, or a combination of both registered securities and bearer securities. If we issue senior debt securities as bearer securities, they will have interest coupons attached unless we elect to issue them as zero coupon securities. If we issue bearer securities, we may describe material U.S. federal income tax consequences and other material considerations, procedures and limitations in the applicable prospectus supplement.

Holders of registered debt securities may present the debt securities for exchange for different authorized amounts of other debt securities of the same series and in the same aggregate principal amount at the corporate trust office of the trustee or at the office of any other transfer agent we may designate for the purpose and describe in the applicable prospectus supplement. The registered securities must be duly endorsed or accompanied by a written instrument of transfer. The agent will not impose a service charge on you for the transfer or exchange. We may, however, require that you pay any applicable tax or other governmental charge. If we issue bearer securities, we will describe any procedures for exchanging those bearer securities for other senior debt securities of the same series in the applicable prospectus supplement. Generally, we will not allow you to exchange registered securities for bearer securities.

In general, unless otherwise specified in the applicable prospectus supplement, we will issue registered securities without coupons and in denominations of $1,000 or integral multiples, and bearer securities in denominations of $5,000. We may issue both registered and bearer securities in global form.

Conversion and Exchange

If any debt securities will be convertible into or exchangeable for our common stock, preferred stock or other securities, the applicable prospectus supplement will set forth the terms and conditions of the conversion or exchange, including:

Redemption

Unless otherwise indicated in the applicable prospectus supplement, we may, at our option, redeem any series of debt securities in whole at any time or in part from time to time. If any series of debt securities are redeemable only on or after a certain date or only upon satisfaction of additional conditions, the applicable prospectus supplement will specify the date or the additional conditions. Unless otherwise specified in the applicable prospectus supplement, the redemption price for debt securities will equal 100% of the principal amount plus any accrued and unpaid interest on those debt securities.

The applicable prospectus supplement will contain the specific terms on which we may redeem a series of debt securities prior to its stated maturity. Unless otherwise described in the prospectus supplement relating to a particular offering, we will send a notice of redemption to holders at least 30 days but not more than 60 days prior to the redemption date. The notice will state:

On or before any redemption date, we will deposit an amount of money with the trustee or with a paying agent sufficient to pay the redemption price.

Unless otherwise described in the prospectus supplement relating to a particular offering, if we are redeeming less than all the debt securities, the trustee will select the debt securities to be redeemed using a method it considers fair and appropriate. After the redemption date, holders of redeemed debt securities will have no rights with respect to the debt securities except the right to receive the redemption price and any unpaid interest to the redemption date.

Events of Default

Unless otherwise described in the prospectus supplement relating to a particular offering, an "event of default" regarding any series of debt securities is any one of the following events:

We are required to file every year with each trustee an officers’ certificate stating whether any default exists and specifying any default that exists.

Acceleration of Maturity

Unless otherwise described in the prospectus supplement relating to a particular offering, if an event of default has occurred and is continuing with respect to debt securities of a particular series (except, in the case of subordinated debt securities, defaults relating to bankruptcy events), the trustee or the holders of not less than 25% in principal amount of outstanding debt securities of that series may declare the principal amount of outstanding debt securities of that series due and payable immediately.

Unless otherwise described in the prospectus supplement relating to a particular offering, at any time after a declaration of acceleration of maturity with respect to debt securities of any series has been made and before a judgment or decree for payment of the money due has been obtained by the trustee, the holders of a majority in principal amount of the outstanding debt securities of that series by written notice to us and the trustee, may rescind and annul the declaration and its consequences if:

No rescission will affect any subsequent default or impair any right consequent thereon.

Waiver of Defaults

Unless otherwise described in the prospectus supplement relating to a particular offering, the holders of not less than a majority in principal amount of the outstanding debt securities of any series may, on behalf of the holders of all the debt securities of the series and any related coupons, waive any past default under the applicable indenture with respect to the series and its consequences, except a default:

If an event of default with respect to debt securities of a particular series occurs and is continuing, the trustee will not be obligated to exercise any of its rights or powers under the applicable indenture at the request or direction of any of the holders of debt securities of the series, unless the holders have offered to the trustee reasonable indemnity and security against the costs, expenses and liabilities that might be incurred by it in compliance with the request.

The holders of a majority in principal amount of the outstanding debt securities of any series have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee under the applicable indenture, or exercising any trust or power conferred on the trustee with respect to the debt securities of that series. The trustee may refuse to follow directions in conflict with law or the indenture that may expose the trustee to personal liability or may be unduly prejudicial to the other, non-directing holders. Additionally, the trustee may take any other action the trustee deems proper which is not inconsistent with the direction.

Modification of Indenture

We and the trustee may, without the consent of any holders of debt securities, enter into supplemental indentures for various purposes, including:

We and the trustee may, with the consent of the holders of not less than a majority in principal amount of the outstanding debt securities of all affected series acting as one class, execute supplemental indentures adding any provisions to or changing or eliminating any of the provisions of the indenture or modifying the rights of the holders of the debt securities of the series. Without the consent of the holders of all the outstanding debt securities affected thereby, no supplemental indenture may:

Consolidation, Merger and Sale of Assets

Unless otherwise described in the prospectus supplement relating to a particular offering, as provided in the indentures, we may not consolidate with or merge into any other person, or convey, transfer or lease all or substantially all of our assets to any other person, unless:

Satisfaction and Discharge

We may terminate our obligations with respect to debt securities of any series not previously delivered to the trustee for cancellation when those debt securities:

We may terminate our obligations with respect to the debt securities of a series by depositing with the trustee, as trust funds in trust dedicated solely for that purpose, an amount sufficient to pay and discharge the entire indebtedness on the debt securities of that series. In that case, the applicable indenture will cease to be of further effect, and our obligations will be satisfied and discharged with respect to that series (except our obligations to pay all other amounts due under the indenture and to provide certain officers’ certificates and opinions of counsel to the trustee). At our expense, the trustee will execute proper instruments acknowledging the satisfaction and discharge.

The Trustees

Any trustee may be deemed to have a conflicting interest for purposes of the Trust Indenture Act and may be required to resign as trustee if there is an event of default under the applicable indenture and, as more fully described in Section 310(b) of the Trust Indenture Act, one or more of the following occurs:

We may appoint an alternative trustee for any series of debt securities. The appointment of an alternative trustee would be described in the applicable prospectus supplement.

We and our affiliates may engage in transactions with the trustee and its affiliates in the ordinary course of business.

Governing Law

Each of the indentures are, and the related senior debt securities and subordinated debt securities will be, governed by and construed under the internal laws of the State of New York.

DESCRIPTION OF THE WARRANTS

We may issue warrants to purchase debt securities, preferred stock or common stock. We may offer warrants separately or together with one or more additional warrants, debt securities, shares of preferred stock or common stock, or any combination of those securities in the form of units, as described in the applicable prospectus supplement. If we issue warrants as part of a unit, the prospectus supplement will specify whether those warrants may be separated from the other securities in the unit prior to the warrants’ expiration date. We may issue the warrants under warrant agreements to be entered into between us and a bank or trust company, as warrant agent, all as described in the prospectus supplement. If we issue the warrants under warrant agreements, the warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants.

We will describe the particular terms of any warrants that we offer in the prospectus supplement relating to those warrants. Those terms may include the following:

Each warrant will entitle the holder thereof to purchase such number of shares of common stock or preferred stock or other securities at the exercise price as will in each case be set forth in, or be determinable as set forth in, the applicable prospectus supplement. Warrants may be exercised at any time up to the close of business on the expiration date set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void. Warrants may be exercised as set forth in the applicable prospectus supplement relating to the warrants offered thereby. Upon receipt of payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will, as soon as practicable, forward the purchased securities. If less than all of the warrants represented by the warrant certificate are exercised, a new warrant certificate will be issued for the remaining warrants.

DESCRIPTION OF UNITS

We may issue, in one or more series, units comprised of shares of our common stock or preferred stock, warrants to purchase common stock or preferred stock, debt securities or any combination of those securities. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security.

We may evidence units by unit certificates that we issue under a separate agreement. We may issue the units under a unit agreement between us and one or more unit agents. If we elect to enter into a unit agreement with a unit agent, the unit agent will act solely as our agent in connection with the units and will not assume any obligation or relationship of agency or trust for or with any registered holders of units or beneficial owners of units. We will indicate the name and address and other information regarding the unit agent in the applicable prospectus supplement relating to a particular series of units if we elect to use a unit agent.

We will describe in the applicable prospectus supplement the terms of the series of units being offered, including: (i) the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately; (ii) any provisions of the governing unit agreement that differ from those described herein; and (iii) any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units.

The other provisions regarding our common stock, preferred stock, warrants and debt securities as described in this section will apply to each unit to the extent such unit consists of shares of our common stock, preferred stock, warrants and/or debt securities.

PLAN OF DISTRIBUTION

We may sell the securities covered by this prospectus in one or more of the following ways from time to time:

In addition, we may enter into derivative or other hedging transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. The applicable prospectus supplement may indicate that third parties may sell securities covered by this prospectus and the prospectus supplement, including in short sale transactions, in connection with those derivatives. If so, the third party may use securities we pledge or that are borrowed from us or others to settle those sales or to close out any related open borrowings of stock, and may use securities received from us in settlement of those derivatives to close out any related open borrowings of stock. The third party in those sale transactions will be an underwriter and, if applicable, will be identified in the prospectus supplement (or a post-effective amendment thereto).

A prospectus supplement with respect to each series of securities will include, to the extent applicable:

Any offer and sale of the securities described in this prospectus by us, any underwriters, or other third parties described above may be effected from time to time in one or more transactions, including, without limitation, privately negotiated transactions, either:

Offerings of securities covered by this prospectus also may be made into an existing trading market for those securities in transactions at other than a fixed price, either:

•              on or through the facilities of the NASDAQ Capital Market or any other securities exchange or quotation or trading service on which those securities may be listed, quoted, or traded at the time of sale; and/or

•              to or through a market maker otherwise than on the NASDAQ Capital Market or those other securities exchanges or quotation or trading services.

Those at-the-market offerings, if any, will be conducted by underwriters acting as our principal or agent, who may also be third-party sellers of securities as described above.

In addition, we may sell some or all of the securities covered by this prospectus through:

•              purchases by a dealer, as principal, who may then resell those securities to the public for its account at varying prices determined by the dealer at the time of resale or at a fixed price agreed to with us at the time of sale;

•              block trades in which a dealer will attempt to sell as agent, but may position or resell a portion of the block as principal in order to facilitate the transaction; and/or

•              ordinary brokerage transactions and transactions in which a broker-dealer solicits purchasers.

Any dealer may be deemed to be an underwriter, as that term is defined in the Securities Act of 1933 of the securities so offered and sold.

In connection with offerings made through underwriters or agents, we may enter into agreements with those underwriters or agents pursuant to which we receive our outstanding securities in consideration for the securities being offered to the public for cash. In connection with these arrangements, the underwriters or agents also may sell securities covered by this prospectus to hedge their positions in any such outstanding securities, including in short sale transactions. If so, the underwriters or agents may use the securities received from us under those arrangements to close out any related open borrowings of securities.

We may loan or pledge securities to a financial institution or other third party that in turn may sell the loaned securities or, in any event of default in the case of a pledge, sell the pledged securities using this prospectus and the applicable prospectus supplement. That financial institution or third party may transfer its short position to investors in our securities or in connection with a simultaneous offering of other securities covered by this prospectus.

We may solicit offers to purchase the securities covered by this prospectus directly from, and we may make sales of such securities directly to, institutional investors or others, who may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale of such securities.

The securities may also be offered and sold, if so indicated in a 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 agents for us.

If indicated in the applicable prospectus supplement, we may sell the securities through agents from time to time. We generally expect that any agent will be acting on a "best efforts" basis for the period of its appointment.

If underwriters are used in any sale of any securities, the securities may be either offered to the public through underwriting syndicates represented by managing underwriters, or directly by underwriters. Unless otherwise stated in a prospectus supplement, the obligations of the underwriters to purchase any securities will be conditioned on customary closing conditions, and the underwriters will be obligated to purchase all of that series of securities, if any are purchased.

Underwriters, dealers, agents, and remarketing firms may at the time of any offering of securities be entitled under agreements entered into with us to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments that the underwriters, dealers, agents, and remarketing firms may be required to make. Underwriters, dealers, agents, and remarketing agents may be customers of, engage in transactions with, or perform services in the ordinary course of business for us and/or our affiliates.

Any underwriters to whom securities covered by this prospectus are sold by us for public offering and sale, if any, may make a market in the securities, but those underwriters will not be obligated to do so and may discontinue any market making at any time without notice.

LEGAL MATTERS

Schiff Hardin LLP, Washington, DC, will pass upon the validity of the securities offered by this prospectus for us. Legal matters will be passed upon for any underwriters, dealers or agents by counsel named in the applicable prospectus supplement.

EXPERTS

The audited financial statements incorporated by reference in this prospectus and elsewhere in the registration statement have been so incorporated by reference in reliance upon the report of Grant Thornton LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing.

$20,000,000 and 161,681 Shares of Common Stock

Common Stock

PROSPECTUS SUPPLEMENT

June 25, 2021