We are offering directly to two separate investors 600,000 shares of our common stock for an aggregate purchase price of $1,800,000.

Our common stock is traded on the Nasdaq Global Market under the symbol “ETON.” On March 26, 2020, the closing price of our common stock on the Nasdaq Global Market was $3.33 per share.

Investing in our securities involves a high degree of risk. You should carefully consider the information under the heading “Risk Factors” set forth on page S-3 of this prospectus supplement, on page 2 of the accompanying prospectus, as well as in our periodic reports filed with the Securities and Exchange Commission and incorporated by reference herein, in determining whether 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 supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This prospectus supplement is not complete without, and may not be utilized except in connection with, the accompanying prospectus dated December 16, 2019, and any amendments to such prospectus. This prospectus supplement provides supplemental information regarding the Company, updates and changes information contained in the accompanying prospectus and describes the specific terms of this offering. The accompanying prospectus gives more general information, some of which may not apply to this offering. We incorporate by reference important information into this prospectus supplement and the accompanying prospectus. You may obtain the information incorporated by reference into this prospectus supplement and the accompanying prospectus without charge by following the instructions under “Incorporation of Certain Information by Reference” in this prospectus supplement and “Where You Can Find Additional Information About Us” in the accompanying prospectus. You should carefully read both this prospectus supplement and the accompanying prospectus, as well as additional information described under “Incorporation of Certain Information by Reference,” before deciding to invest in shares of our common stock. If the information in, or incorporated by reference in, this prospectus supplement conflicts with information in the accompanying prospectus or a document incorporated by reference herein or therein, the information in, or incorporated by reference in, this prospectus supplement shall control.

All references in this prospectus supplement to “Eton,” “the Company,” “we,” “us” or “our” mean Eton Pharmaceuticals, Inc., unless we state otherwise or the context otherwise requires.

In making your investment decision, you should rely only on the information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and any free writing prospectus filed by us with the U.S. Securities and Exchange Commission (“SEC”) and any other offering material we may provide. We have not authorized anyone to provide you with different or additional information. If anyone provides you with different or additional information, you should not rely on it. We are not making an offer to sell these securities under any circumstance or in any jurisdiction where the offer is not permitted or is unlawful. You should assume that the information contained in this prospectus supplement and the accompanying prospectus is accurate only as of their respective dates, and that any information in documents that we have incorporated by reference is accurate only as of the date of the document incorporated by reference. Our business, financial condition, results of operations, cash flows and prospects may have changed since those dates.

The following summary is qualified in its entirety by, and should be read together with, the more detailed information and our consolidated financial statements and related notes thereto appearing elsewhere or incorporated by reference in this prospectus supplement and the accompanying prospectus. Before you decide to invest in our securities, you should read the entire prospectus supplement and the accompanying prospectus carefully, including the risk factors and the financial statements and related notes included or incorporated by reference in this prospectus supplement and the accompanying prospectus.

We were formed in April 2017 as a specialty pharmaceutical company focused on developing and commercializing innovative pharmaceutical products. We seek to improve the formula, delivery system, or safety of existing molecules in order to address unmet patient needs. We pursue what we perceive to be low-risk candidates where existing published literature, historical clinical trials, or physician usage has established safety and/or efficacy of the molecule, thereby reducing the incremental clinical burden required for us to bring the product to patients.

In October 2019, we received U.S. Food and Drug Administration (“FDA”) approval for Biorphen® which we will market in the United States. Biorphen (phenylephrine HCl injection) is an alpha-1 adrenergic receptor agonist indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia. We acquired U.S marketing rights to Biorphen in February 2019.

We have established a diversified pipeline of product candidates in various stages of development, including multiple candidates that have been submitted to the FDA for review. Our product candidates are primarily focused on two core areas: hospital-based products and pediatric oral liquid products. We believe these candidates can address situations where patient needs are not being met by current FDA-approved products.

We were incorporated under the laws of the state of Delaware in April 2017. We were initially a wholly owned subsidiary of Harrow Health Inc. (“Harrow”) but are no longer a subsidiary of Harrow. Our principal executive offices are located at 21925 W. Field Parkway, Suite 235, Deer Park, Illinois, 60010, and our telephone number is (847) 787-7361. Our corporate website address is www.etonpharma.com, to which we regularly post copies of our press releases as well as links to reports we have filed with the SEC, which are available free of charge as soon as reasonably practicable after being electronically filed with or furnished to the SEC. Interested persons can subscribe on our website to email alerts that are sent automatically when we issues press releases, file reports with the SEC or post certain other information to our website. We do not incorporate the information on our website into this prospectus supplement or the accompanying prospectus and you should not consider it part of this prospectus supplement or the accompanying prospectus.

The following summary contains basic information about this offering. The summary is not intended to be complete. You should read the full text and more specific details contained elsewhere in this prospectus supplement.

This prospectus supplement and the accompanying prospectus, including the sections entitled “Prospectus Supplement Summary,” “Risk Factors,” and “Use of Proceeds,” contain forward-looking statements. The words “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” and similar expressions that convey uncertainty of future events or outcomes are intended to identify forward-looking statements. These forward-looking statements include, but are not limited to, statements concerning the following:

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in “Risk Factors” below and elsewhere in this prospectus supplement and the accompanying prospectus. Moreover, we operate in a very competitive and rapidly changing environment, and new risks emerge from time to time. It is not possible for us to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus supplement and the accompanying prospectus may not occur and actual results could differ materially and adversely from those anticipated or implied in our forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in our forward-looking statements are reasonable, we cannot guarantee that the future results, levels of activity, performance or events and circumstances described in the forward-looking statements will be achieved or occur. Moreover, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this prospectus supplement to conform these statements to actual results or to changes in our expectations, except as required by law.

You should read this prospectus supplement and the accompanying prospectus and the documents that we reference in this prospectus supplement and the accompanying prospectus and have filed with the SEC as exhibits to the registration statement of which the accompanying prospectus is a part with the understanding that our actual future results, levels of activity, performance and events and circumstances may be materially different from what we expect

An investment in our securities involves a high degree of risk. You should carefully consider all of the information in this prospectus supplement and the accompanying prospectus, including the risks and uncertainties described below, and all other information included or incorporated by reference in this prospectus supplement and the accompanying prospectus, before you decide whether to purchase our securities. You should also carefully consider the risks and uncertainties under the heading “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2019, which we filed with the SEC on March 5, 2020, which is incorporated by reference in this prospectus supplement, as well as any updates thereto contained in subsequent filings with the SEC.

The risks and uncertainties we describe are not the only ones facing us. Additional risks not presently known to us or that we currently deem immaterial may also impair our business operations. If any of these risks were to occur, our business, financial condition or results of operations would likely suffer. In that event, the trading price of our common stock could decline and you could lose all or part of your investment.

Our business may be adversely affected by the ongoing coronavirus pandemic.

The outbreak of the novel Coronavirus (COVID-19) has evolved into a global pandemic. The coronavirus has spread to many regions of the world. The extent to which COVID-19 and global efforts to contain its spread will impact our business including our operations, preclinical studies, clinical trials, and financial condition will depend on future developments, which are highly uncertain and cannot be predicted at this time, and include the duration, severity, and scope of the pandemic and the actions taken by other parties, such as governmental authorities, to contain and treat COVID-19.

If you purchase the common stock sold in this offering, you will experience immediate and substantial dilution in your investment. You may experience further dilution if we issue additional equity securities in future fundraising transactions.

Since the price per share of our common stock being offered is substantially higher than the net tangible book value per share of our common stock, you will suffer substantial dilution with respect to the net tangible book value of the common stock you purchase in this offering. Based on the public offering price of $3.00 per share and our net tangible book value as of December 31, 2019 (as adjusted for a $0.24 increase per share due to our sale of shares of common stock in March 2020), if you purchase shares of common stock in this offering, you will suffer immediate and substantial dilution of $2.15 per share with respect to the net tangible book value of the common stock. See the section entitled “Dilution” elsewhere in this prospectus supplement for a more detailed discussion of the dilution you will incur if you purchase common stock in this offering.

If we issue additional common stock, or securities convertible into or exchangeable or exercisable for common stock, our stockholders, including any investor who purchases shares of common stock in this offering, could experience additional dilution, and any such issuances may result in downward pressure on the price of our common stock.

We anticipate that the net proceeds from the sale of the securities offered under this prospectus supplement will be used for business expansion and general corporate purposes, which may include, among other things, repayment of debt, capital expenditures, the financing of possible acquisitions or in-licensing of additional product candidates, increasing our working capital and the financing of ongoing operating expenses and overhead. Pending the application of the net proceeds, we expect to invest the proceeds in marketable securities and short-term investments.

We are offering 600,000 shares of our common stock. The material terms and provisions of our common stock are described under the caption “Capital Stock” starting on page 3 of the accompanying prospectus.

If you invest in our securities, your interest will be diluted by an amount equal to the difference between the public offering price and the net tangible book value per share of our common stock after this offering. We calculate net tangible book value per share by dividing our net tangible book value (total assets less intangible assets and total liabilities) by the number of outstanding shares of common stock.

Our net tangible book value at December 31, 2019 was approximately $9.8 million, or $0.55 per share of common stock and the sale by us of 2,000,000 shares of common stock in March 2020 for approximately $5.9 million increased the net tangible book value to $15.7 million, or $0.79 per share. After giving effect to the sale of 600,000 shares of common stock offered hereby, and our receipt of the expected proceeds from the sale of those shares, our adjusted net tangible book value at March 26, 2020 would be approximately $17.5 million, or $0.85 per share. This represents an immediate increase in as-adjusted net tangible book value of $0.06 per share to existing stockholders and an immediate and substantial dilution of $2.15 per share to the investors in this offering. The following table illustrates this per share dilution:

The table and discussion above are based on 20,482,486 shares of our common stock outstanding after this offering and excludes the following:

We have agreed to sell directly to two investors all of the shares of common stock offered by this prospectus supplement. No underwriters or agents were engaged by us for this transaction. We have entered into a purchase agreement (the “Purchase Agreement”) directly with those investors in connection with this offering. The Purchase Agreement contains customary representations, warranties and covenants for transactions of this type.

The purchase and sale of our common stock under the Purchase Agreement are registered pursuant to our shelf registration statement on Form S-3 File Number 333- 235329 as to which this prospectus supplement relates.

The validity of the common stock being offered hereby will be passed upon by Croke Fairchild Morgan & Beres LLC, Chicago, Illinois.

The financial statements of the Company as of and for the periods ended December 31, 2019 and 2018, included in our Annual Report on Form 10-K filed with the SEC on March 5, 2020, were audited by KMJ Corbin & Company LLP, an independent registered public accounting firm, as stated in their report which is incorporated herein by reference. Such financial statements have been so incorporated in reliance on the report of such firm given upon their authority as experts in accounting and auditing.

This prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3, including amendments, relating to the common stock offered by this prospectus supplement and the accompanying prospectus, which have been filed with the SEC. This prospectus supplement and the accompanying prospectus do not contain all of the information set forth in the registration statement and the exhibits and schedules thereto, certain parts of which are omitted in accordance with the rules and regulations of the SEC. Statements contained in this prospectus supplement and the accompanying prospectus as to the contents of any contract or other document referred to are not necessarily complete and in each instance reference is made to the copy of that contract or other document filed as an exhibit to the registration statement. For further information about us and the common stock offered by this prospectus supplement and the accompanying prospectus we refer you to the registration statement and the exhibits and schedules which may be obtained as described below.

This prospectus supplement and the accompanying prospectus “incorporate by reference” information that we have filed with the SEC under the Securities Exchange Act of 1934 (the “Exchange Act”). This means that we are disclosing important information to you by referring you to those documents. Information contained in any document subsequently filed with the SEC, to the extent it modifies information in this prospectus supplement, in the accompanying prospectus or in any document incorporated by reference in this prospectus supplement or the accompanying prospectus, will automatically update and supersede the information originally included in this prospectus supplement, the accompanying prospectus or any document incorporated by reference in this prospectus supplement or the accompanying prospectus.

We incorporate by reference the following documents that we previously filed with the SEC pursuant to the Securities Act or the Exchange Act and any future filings we will 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 supplement have been sold; provided, however, that we are not incorporating any information furnished to, rather than filed with, the SEC:

Any statement contained in this prospectus supplement or the accompanying prospectus or in a document incorporated or deemed to be incorporated by reference into this prospectus supplement will be deemed to be modified or superseded for purposes hereof to the extent that a statement contained in this prospectus supplement or the accompanying prospectus or any other subsequently filed document that is deemed to be incorporated by reference into this prospectus supplement modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement and the accompanying prospectus.

The documents incorporated by reference in this prospectus supplement may be obtained from us without charge and will be provided to each person, including any beneficial owner, to whom a prospectus supplement is delivered. You may obtain a copy of the documents at no cost by submitting a written request to 21925 W. Field Parkway, Suite 235, Deer Park, Illinois, 60010, or through our telephone number at (847) 787-7361. Further information can be obtained through our website address, www.etonpharma.com. Such additional information contained in our website is not a part of this prospectus supplement.

We may offer and sell, from time to time in one or more offerings, any combination of common stock, preferred stock, debt securities, warrants, subscription rights or units having a maximum aggregate offering price of $100,000,000. When we decide to sell a particular class or series of securities, we will provide specific terms of the offered securities in a prospectus supplement.

The prospectus supplement may also add, update or change information contained in or incorporated by reference into this prospectus. However, no prospectus supplement shall offer a security that is not registered and described in this prospectus at the time of its effectiveness. You should read this prospectus and any prospectus supplement, as well as the documents incorporated by reference or deemed to be incorporated by reference into this prospectus or a prospectus supplement, carefully before you invest. This prospectus may not be used to offer or sell our securities unless accompanied by a prospectus supplement relating to the offered securities.

Our common stock is traded on the Nasdaq Global Market under the symbol “ETON.” Each prospectus supplement will contain information, where applicable, as to our listing on the Nasdaq Global Market or any other securities exchange of the securities covered by the prospectus supplement.

These securities may be sold directly by us, through dealers or agents designated from time to time, to or through underwriters or through a combination of these methods. See “Plan of Distribution” in this prospectus. We may also describe the plan of distribution for any particular offering of our securities in a prospectus supplement. If any agents, underwriters or dealers are involved in the sale of any securities in respect of which this prospectus is being delivered, we will disclose their names and the nature of our arrangements with them in a prospectus supplement. The net proceeds we expect to receive from any such sale will also be included in a prospectus supplement.

As of November 27, 2019, the aggregate market value of our common stock held by non-affiliates was approximately $77.6 million based on 17,807,167 outstanding shares of common stock, of which 12,271,173 shares are held by non-affiliates, and a price of $6.32 per share, which was the last reported sale price of our common stock on the Nasdaq Global Market on that date.

We were incorporated under the laws of Delaware in April 2017. Our principal executive offices are located at 21925 W. Field Parkway, Suite 235, Deer Park, Illinois, 60010, and our telephone number is (847) 787-7361.

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

Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties referenced under the heading “Risk Factors” on page 2 of this prospectus as well as those contained in the applicable prospectus supplement and any related free writing prospectus, and in the other documents that are incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

This prospectus, including the sections entitled “Prospectus Summary,” “Risk Factors,” “Use of Proceeds,” contains forward-looking statements. The words “believe,” “may,” “will,” “potentially,” “estimate,” “continue,” “anticipate,” “intend,” “could,” “would,” “project,” “plan,” “expect” and similar expressions that convey uncertainty of future events or outcomes are intended to identify forward-looking statements. These forward-looking statements include, but are not limited to, statements concerning the following:

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in “Risk Factors” and elsewhere in this prospectus. Moreover, we operate in a very competitive and rapidly changing environment, and new risks emerge from time to time. It is not possible for us to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this prospectus may not occur and actual results could differ materially and adversely from those anticipated or implied in our forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in our forward-looking statements are reasonable, we cannot guarantee that the future results, levels of activity, performance or events and circumstances described in the forward-looking statements will be achieved or occur. Moreover, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this prospectus to conform these statements to actual results or to changes in our expectations, except as required by law.

You should read this prospectus and the documents that we reference in this prospectus and have filed with the Securities and Exchange Commission (“SEC”) as exhibits to the registration statement of which this prospectus is a part with the understanding that our actual future results, levels of activity, performance and events and circumstances may be materially different from what we expect.

This prospectus is part of a registration statement that we filed with the SEC using a “shelf” registration process. Under this shelf registration process, we may offer from time to time securities having a maximum aggregate offering price of $100,000,000. Each time we offer securities, we will prepare and file with the SEC a prospectus supplement and/or a free writing prospectus (collectively referred to herein as a “prospectus supplement”) that describes the specific amounts, prices and terms of the securities we offer. The prospectus supplement also may add, update or change information contained in this prospectus or the documents incorporated herein by reference. You should read carefully both this prospectus and any prospectus supplement together with additional information described below under the caption “Where You Can Find Additional Information About Us.”

This prospectus does not contain all the information provided in the registration statement we filed with the SEC. For further information about us or our securities offered hereby, you should refer to that registration statement, which you can obtain from the SEC as described below under “Where You Can Find Additional Information About Us.”

You should rely only on the information contained or incorporated by reference in this prospectus or any prospectus supplement. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus is not an offer to sell securities, and it is not soliciting an offer to buy securities, in any jurisdiction where the offer or sale is not permitted. You should assume that the information appearing in this prospectus or any prospectus supplement, as well as information we have previously filed with the SEC and incorporated by reference, is accurate as of the date of those documents only. Our business, financial condition, results of operations and prospects may have changed since those dates.

We may sell securities through underwriters or dealers, through agents, directly to purchasers or through any combination of these methods. We and our agents reserve the sole right to accept or reject in whole or in part any proposed purchase of securities. The prospectus supplement, which we will prepare and file with the SEC each time we offer securities, will set forth the names of any underwriters, agents or others involved in the sale of securities, and any applicable fee, commission or discount arrangements with them. See “Plan of Distribution.”

As used, or incorporated by reference, in this prospectus, unless otherwise stated or the context requires otherwise, the “Company” and terms such as “we,” “us” “our,” and “Eton” refer to Eton Pharmaceuticals, Inc, a Delaware corporation.

PROSPECTUS SUMMARY

The following summary, because it is a summary, may not contain all the information that may be important to you. This prospectus incorporates important business and financial information about Eton that is not included in, or delivered with, this prospectus. Before making an investment, you should read the entire prospectus and any amendment carefully. You should also carefully read the risks of investing discussed under “Risk Factors” and the financial statements included in our other filings with the SEC, including in our most recent Annual Report on Form 10-K which we filed with the SEC on March 25, 2019. This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find Additional Information About Us.”

We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, a copy of any or all of the information that has been incorporated by reference in this prospectus but not delivered with this prospectus. You may request a copy of these filings, excluding the exhibits to such filings which we have not specifically incorporated by reference in such filings, at no cost, by writing us at the following address: 21925 W. Field Parkway, Suite 235, Deer Park, Illinois, 60010.

Our Company

In October 2019, we received FDA approval for Biorphen® which we will market in the United States. Biorphen (phenylephrine HCl injection) is an alpha-1 adrenergic receptor agonist indicated for the treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesia. We acquired U.S marketing rights to Biorphen in February 2019.

The Offering

This prospectus is part of a registration statement that we filed with the SEC utilizing a shelf registration process. Under this shelf registration process, we may sell any combination of:

	●	common stock;

	●	preferred stock;

	●	debt securities;

	●	warrants to purchase any of the securities listed above;

	●	subscription rights to purchase any of the securities listed above; and/or

	●	units consisting of one or more of the foregoing,

in one or more offerings up to a total dollar amount of $100 million. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that specific offering and include a discussion of any risk factors or other special considerations that apply to those securities. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with the additional information described under the heading “Where You Can Find Additional Information About Us.”

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find Additional Information About Us.”

Investing in our securities involves a high degree of risk. Before purchasing our securities, you should carefully consider the risks and uncertainties set forth below and under the heading “Risk Factors” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018, which we filed with the SEC on March 25, 2019, which is incorporated by reference in this prospectus, as well as any updates thereto contained in subsequent filings with the SEC or any applicable prospectus supplement Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also impair our business operations. Additional risk factors may be included in a prospectus supplement for a particular offering of securities.

Future sales or other dilution of our equity could depress the market price of our common stock.

Our common stock is listed on the Nasdaq Global Market. However, trading volume has been limited and a more active public market for our common stock may not develop or be sustained over time. The market price of our common stock could be subject to significant fluctuations. The price of our stock may change in response to variations in our operating results and also may change in response to other factors, including factors specific to companies in our industry many of which are beyond our control. Our shares may be less liquid than the shares of other public companies and there may be imbalances between supply and demand for our shares. As a result, our share price may experience significant volatility and may not necessarily reflect the value of our expected performance. Moreover, sales of our common stock in the public market, or the perception that such sales could occur, could negatively impact the price of our common stock. As a result, you may not be able to sell your shares of our common stock in short time periods, or possibly at all, and the price per share of our common stock may fluctuate significantly.

In addition, the issuance of additional shares of our common stock pursuant to this prospectus, or issuances of securities convertible into or exercisable for our common stock or other equity-linked securities, including preferred stock, warrants, debt securities or units, would dilute the ownership interest of our common shareholders and could depress the market price of our common stock and impair our ability to raise capital through the sale of additional equity securities.

We expect to seek to raise additional capital. If this additional financing is obtained through the issuance of equity securities, debt convertible into equity or options or warrants to acquire equity securities, our existing shareholders could experience significant dilution upon the issuance, conversion or exercise of such securities.

Our management will have broad discretion over the use of the proceeds we receive from the sale of our securities pursuant to this prospectus and might not apply the proceeds in ways that increase the value of your investment.

Our management will have broad discretion to use the net proceeds from any offerings under this prospectus, and you will be relying on the judgment of our management regarding the application of these proceeds. Except as described in any prospectus supplement (including any related free-writing prospectus) that we may authorize to be provided to you, the net proceeds received by us from our sale of the securities described in this prospectus will be added to our general funds and will be used for our general corporate purposes. Our management might not apply the net proceeds from the offering of our securities in ways that increase the value of your investment and might not be able to yield a significant return, if any, on any investment of such net proceeds. You may not have the opportunity to influence our decisions on how to use such proceeds.

Except as may be stated in the applicable prospectus supplement, we intend to use the net proceeds we receive from the sale of the securities offered by this prospectus for business expansion and general corporate purposes, which may include, among other things, repayment of debt, capital expenditures, the financing of possible acquisitions or in-licensing of additional product candidates, increasing our working capital and the financing of ongoing operating expenses and overhead. Pending the application of the net proceeds, we may invest the proceeds in marketable securities and short-term investments.

We will set forth in a prospectus supplement the following information regarding any material dilution of the equity interests of investors purchasing securities in an offering under this prospectus:

The descriptions of the securities contained in this prospectus, together with any applicable prospectus supplement, summarize all the material terms and provisions of the various types of securities that we may offer. We will describe in the applicable prospectus supplement relating to a particular offering the specific terms of the securities offered by that prospectus supplement. We will indicate in the applicable prospectus supplement if the terms of the securities differ from the terms we have summarized below. We will also include in the prospectus supplement information, where applicable, material United States federal income tax considerations relating to the securities.

This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

As of November 27, 2019, our authorized capital stock consists of 50,000,000 shares of common stock, par value $0.001 per share, of which 17,807,167 shares are issued and outstanding, held of record by approximately 18 stockholders, and 10,000,000 shares of preferred stock, par value $0.001 per share, of which none are issued and outstanding. The following description summarizes the most important terms of our capital stock. Because it is only a summary, it does not contain all the information that may be important to you. For a complete description, you should refer to our Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws and to the applicable provisions of Delaware law.

The authorized and unissued shares of common stock and preferred stock are available for issuance without further action by our stockholders, unless such action is required by applicable law or the rules of any stock exchange on which our securities may be listed. Unless approval of our stockholders is so required, our board of directors will not seek stockholder approval for the issuance and sale of our common stock or our preferred stock.

Holders of shares of common stock are entitled to one vote per share on all matters to be voted upon by the stockholders generally. Stockholders are entitled to receive such dividends as may be declared from time to time by the board of directors out of funds legally available therefor, and in the event of liquidation, dissolution or winding up of the company to share ratably in all assets remaining after payment of liabilities. The holders of shares of common stock have no preemptive, conversion, subscription or cumulative voting rights.

Our Amended and Restated Certificate of Incorporation authorizes the issuance of preferred stock (“Preferred Stock”) from time to time in one or more series. The Board of Directors of the Company (the “Board of Directors”) is hereby expressly authorized to provide for the issue of any or all of the unissued and undesignated shares of the Preferred Stock in one or more series, and to fix the number of shares and to determine or alter for each such series, such voting powers, full or limited, or no voting powers, and such designation, preferences, and relative, participating, optional, or other rights and such qualifications, limitations, or restrictions thereof, as shall be stated and expressed in the resolution or resolutions adopted by the Board of Directors providing for the issuance of such shares and as may be permitted by the Delaware General Corporation Law (“DGCL”). The Board of Directors is also expressly authorized to increase or decrease the number of shares of any series subsequent to the issuance of shares of that series, but not below the number of shares of such series then outstanding. In case the number of shares of any series shall be decreased in accordance with the foregoing sentence, the shares constituting such decrease shall resume the status that they had prior to the adoption of the resolution originally fixing the number of shares of such series. The number of authorized shares of Preferred Stock may be increased or decreased (but not below the number of shares thereof then outstanding) by the affirmative vote of the holders of a majority of the voting power of the stock of the Company entitled to vote thereon, without a separate vote of the holders of the Preferred Stock, or of any series thereof, unless a vote of any such holders is required pursuant to the terms of any certificate of designation filed with respect to any series of Preferred Stock.

If the Preferred Stock contains any restriction on the repurchase or redemption of shares by the registrant while there is any arrearage in the payment of dividends or sinking fund installments, such restrictions will be described in the prospectus supplement.

The transfer agent and registrar for our common stock is Computershare Investor Services. Its address is 462 S. Fourth Street, Suite 1600, Louisville, KY 40202 and its telephone number is (800) 962-4284. Our common stock is listed on the Nasdaq Global Market under the symbol “ETON.”

See “Where You Can Find Additional Information About Us” elsewhere in this prospectus for information on where you can obtain copies of our Amended and Restated Certificate of Incorporation and our Amended and Restated Bylaws, which have been filed with and are publicly available from the SEC.

The following description, together with the additional information we may include in any applicable prospectus supplement, summarizes the material terms and provisions of the warrants that we may offer under this prospectus and any related warrant agreements and warrant certificates. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the specific terms of any series of warrants in more detail in the applicable prospectus supplement. If we indicate in the prospectus supplement, the terms of any warrants offered under that prospectus supplement may differ from the terms described below. Specific warrant agreements will contain additional important terms and provisions and will be incorporated by reference as an exhibit to the registration statement which includes this prospectus.

We may issue warrants for the purchase of common stock, preferred stock and debt securities in one or more series. We may issue warrants independently or together with common stock, preferred stock and debt securities, and the warrants may be attached to or separate from these securities.

We may evidence each series of warrants by warrant certificates that we may issue under a separate agreement. We may enter into a warrant agreement with a warrant agent. Each warrant agent may be a bank, transfer agent or trust company that we select which has its principal office in the United States. We may also choose to act as our own warrant agent. We will indicate the name and address of any warrant agent in the applicable prospectus supplement relating to a particular series of warrants.

We will describe in the applicable prospectus supplement the terms of the series of warrants, including:

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to 5:00 P.M. eastern time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information and paying the required exercise price by the methods provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate, and in the applicable prospectus supplement, the information that the holder of the warrant will be required to deliver to the warrant agent.

Upon receipt of the required 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 issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants.

Any warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank, transfer agent or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action the holder’s right to exercise, and receive the securities purchasable upon exercise of, its warrants in accordance with their terms.

No warrant agreement will be qualified as an indenture, and no warrant agent will be required to qualify as a trustee, under the Trust Indenture Act. Therefore, holders of warrants issued under a warrant agreement will not have the protection of the Trust Indenture Act with respect to their warrants.

Each warrant agreement and any warrants issued under the warrant agreements will be governed by the law identified in the applicable prospectus supplement.

Any calculations relating to warrants may be made by a calculation agent, an institution that we appoint as our agent for this purpose. The prospectus supplement for a particular warrant will name the institution that we have appointed to act as the calculation agent for that warrant as of the original issue date for that warrant, if any. We may appoint a different institution to serve as calculation agent from time to time after the original issue date without the consent or notification of the holders. The calculation agent’s determination of any amount of money payable or securities deliverable with respect to a warrant will be final and binding in the absence of manifest error.

We may issue debt securities, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. When we offer to sell debt securities, we will describe the specific terms of any debt securities offered from time to time in a supplement to this prospectus, which may supplement or change the terms outlined below. Senior debt securities will be issued under one or more senior indentures, dated as of a date prior to such issuance, between us and a trustee to be named in a prospectus supplement, as amended or supplemented from time to time. Any subordinated debt securities will be issued under one or more subordinated indentures, dated as of a date prior to such issuance, between us and a trustee to be named in a prospectus supplement, as amended or supplemented from time to time. We have filed forms of the senior trust indenture and subordinated indenture as exhibits to the registration statement of which this prospectus is a part. The indentures will be subject to and governed by the Trust Indenture Act of 1939, as amended.

The indentures in the forms initially filed as exhibits to the registration statement of which this prospectus forms a part do not limit the amount of debt securities that we may issue, including senior debt securities, senior subordinated debt securities, subordinated debt securities and junior subordinated debt securities, and do not limit us from issuing any other debt, including secured and unsecured debt. We may issue debt securities up to an aggregate principal amount as we may authorize from time to time. The terms of each series of debt securities will be established by or pursuant to (a) a supplemental indenture, (b) a resolution of our Board of Directors, or (c) an officers’ certificate pursuant to authority granted under a resolution of our Board of Directors. For the complete terms of the debt securities, you should refer to the applicable prospectus supplement and the form of indentures for those particular debt securities. The prospectus supplement will describe the terms of any debt securities being offered, including:

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

We may issue units comprised of one or more of the other securities described in this prospectus or in any prospectus supplement in any combination. Each unit will be issued so that the holder of the unit is also the holder, with the rights and obligations of a holder, of each security included in the unit. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date or upon the occurrence of a specified event or occurrence.

We may issue subscription rights to purchase common stock, preferred stock, debt securities, warrants, units and other securities described in this prospectus or any combination thereof. These subscription rights may be issued independently or together with any other security offered by us and may or may not be transferable by the stockholder receiving the subscription rights in such offering. In connection with any offering of subscription rights, we may enter into a standby arrangement with one or more underwriters or other investors pursuant to which the underwriters or other investors may be required to purchase any securities remaining unsubscribed for after such offering.

To the extent appropriate, the applicable prospectus supplement will describe the specific terms of the subscription rights to purchase shares of our securities offered thereby, including the following:

Anti-Takeover Effects of Certain Provisions of Delaware Law and Our Charter Documents

The following is a summary of certain provisions of the DGCL, our Amended and Restated Certificate of Incorporation and our Amended and Restated Bylaws. This summary does not purport to be complete and is qualified in its entirety by reference to the DGCL and our Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws.

Effect of Delaware Anti-Takeover Statute. We are subject to Section 203 of the Delaware General Corporation Law, an anti-takeover law. In general, Section 203 prohibits a Delaware corporation from engaging in any business combination (as defined below) with any interested stockholder (as defined below) for a period of three years following the date that the stockholder became an interested stockholder, unless:

In general, Section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation, or who beneficially owns 15% or more of the outstanding voting stock of the corporation at any time within a three-year period immediately prior to the date of determining whether such person is an interested stockholder, and any entity or person affiliated with or controlling or controlled by any of these entities or persons.

Our Charter Documents. Our charter documents include provisions that may have the effect of discouraging, delaying or preventing a change in control or an unsolicited acquisition proposal that a stockholder might consider favorable, including a proposal that might result in the payment of a premium over the market price for the shares held by our stockholders. Certain of these provisions are summarized in the following paragraphs.

Effects of authorized but unissued common stock. One of the effects of the existence of authorized but unissued common stock may be to enable our Board of Directors to make more difficult or to discourage an attempt to obtain control of our Company by means of a merger, tender offer, proxy contest or otherwise, and thereby to protect the continuity of management. If, in the due exercise of its fiduciary obligations, the Board of Directors were to determine that a takeover proposal was not in our best interest, such shares could be issued by the Board of Directors without stockholder approval in one or more transactions that might prevent or render more difficult or costly the completion of the takeover transaction by diluting the voting or other rights of the proposed acquirer or insurgent stockholder group, by putting a substantial voting block in institutional or other hands that might undertake to support the position of the incumbent Board of Directors, by effecting an acquisition that might complicate or preclude the takeover, or otherwise.

Cumulative Voting. Our Amended and Restated Certificate of Incorporation does not provide for cumulative voting in the election of directors, which would allow holders of less than a majority of the stock to elect some directors.

Vacancies. Our Amended and Restated Certificate of Incorporation provides that all vacancies may be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum.

Special Meeting of Stockholders and Stockholder Action by Written Consent. A special meeting of stockholders may only be called by our president, Board of Directors, or such officers or other persons as our board may designate at any time and for any purpose or purposes as shall be stated in the notice of the meeting.

We may sell the securities being offered pursuant to this prospectus to or through underwriters, through dealers, through agents, or directly to one or more purchasers or through a combination of these methods. The applicable prospectus supplement will describe the terms of the offering of the securities, including:

We may distribute the securities from time to time in one or more transactions at:

Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

If underwriters are used in an offering, we will execute an underwriting agreement with such underwriters and will specify the name of each underwriter and the terms of the transaction (including any underwriting discounts and other terms constituting compensation of the underwriters and any dealers) in a prospectus supplement. The securities may be offered to the public either through underwriting syndicates represented by managing underwriters or directly by one or more investment banking firms or others, as designated. If an underwriting syndicate is used, the managing underwriter(s) will be specified on the cover of the prospectus supplement. If underwriters are used in the sale, the offered securities will be acquired by the underwriters for their own accounts and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time. Unless otherwise set forth in the prospectus supplement, the obligations of the underwriters to purchase the offered securities will be subject to conditions precedent, and the underwriters will be obligated to purchase all of the offered securities, if any are purchased.

We may grant to the underwriters options to purchase additional securities to cover over-allotments, if any, at the public offering price, with additional underwriting commissions or discounts, as may be set forth in a related prospectus supplement. The terms of any over-allotment option will be set forth in the prospectus supplement for those securities.

If we use one or more dealers in the sale of the securities being offered pursuant to this prospectus or any prospectus supplement, we will sell the securities to the dealer, as principal. The dealers may then resell the securities to the public at varying prices to be determined by each dealer at the time of resale. The names of the dealers and the terms of the transaction will be specified in a prospectus supplement.

We may sell the securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement.

We may authorize agents or underwriters to solicit offers by institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

In connection with the sale of the securities, underwriters, dealers or agents may receive compensation from us or from purchasers of the securities for whom they act as agents, in the form of discounts, concessions or commissions. Underwriters may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of the securities, and any institutional investors or others that purchase securities directly for the purpose of resale or distribution, may be deemed to be underwriters, and any discounts or commissions received by them from us and any profit on the resale of the securities by them may be deemed to be underwriting discounts and commissions under the Securities Act of 1933 (the “Securities Act”).

We may provide agents, underwriters and other purchasers with indemnification against particular civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents, underwriters or other purchasers may make with respect to such liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

To facilitate the public offering of a series of securities, persons participating in the offering may engage in transactions that stabilize, maintain, or otherwise affect the market price of the securities. This may include over-allotments or short sales of the securities, which involves the sale by persons participating in the offering of more securities than have been sold to them by us. In addition, those persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to underwriters or dealers participating in any such offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. Such transactions, if commenced, may be discontinued at any time. We make no representation or prediction as to the direction or magnitude of any effect that the transactions described above, if implemented, may have on the price of our securities.

Unless otherwise specified in the applicable prospectus supplement, any common stock sold pursuant to a prospectus supplement will be eligible for listing on the Nasdaq Global Market, subject to official notice of issuance. Any underwriters to whom securities are sold by us for public offering and sale may make a market in the securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice.

In order to comply with the securities laws of some states, if applicable, the securities offered pursuant to this prospectus will be sold in those states only through registered or licensed brokers or dealers. In addition, in some states securities may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and complied with.

The DGCL provides that corporations may include a provision in their certificate of incorporation relieving directors of monetary liability for breach of their fiduciary duty as directors, provided that such provision shall not eliminate or limit the liability of a director (i) for any breach of the director’s duty of loyalty to the corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) for unlawful payment of a dividend or unlawful stock purchase or redemption, or (iv) for any transaction from which the director derived an improper personal benefit. Our certificate of incorporation provides that directors are not liable to us or our stockholders for monetary damages for breach of their fiduciary duty as directors to the fullest extent permitted by Delaware law. In addition to the foregoing, our certificate of incorporation provides that we may indemnify directors and officers to the fullest extent permitted by law.

The above provisions in our Amended and Restated Certificate of Incorporation may have the effect of reducing the likelihood of derivative litigation against directors and may discourage or deter stockholders or management from bringing a lawsuit against directors for breach of their fiduciary duty, even though such an action, if successful, might otherwise have benefited us and our stockholders. However, we believe that the foregoing provisions are necessary to attract and retain qualified persons as directors.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to our directors, officers and controlling persons pursuant to the foregoing provisions, or otherwise, we have been advised that in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

Certain legal matters with respect to the validity of certain of the offered securities will be passed upon for us by Croke Fairchild Morgan & Beres LLC, Chicago, Illinois. If counsel for any underwriters passes on legal matters in connection with an offering of the shares of the securities described in this prospectus, we will name that counsel in the prospectus supplement relating to that offering.

The financial statements of the Company as of and for the periods ended December 31, 2018 and 2017, included in our Annual Report on Form 10-K filed on March 25, 2019, were audited by KMJ Corbin & Company LLP, an independent registered public accounting firm, as stated in their report which is incorporated herein by reference in reliance on the report of such firm given upon their authority as experts in accounting and auditing.

This prospectus “incorporates by reference” information that we have filed with the SEC under the Securities Exchange Act of 1934 (the “Exchange Act”). This means that we are disclosing important information to you by referring you to those documents. Information contained in any document subsequently filed with the SEC, to the extent it modifies information in this prospectus or in any document incorporated by reference in this prospectus, will automatically update and supersede the information originally included in this prospectus or any document incorporated by reference in this prospectus.

We incorporate by reference the following documents that we previously filed with the SEC pursuant to the Securities Act or the Exchange Act:

Information in this prospectus supersedes related information in the documents listed above, and information in subsequently filed documents supersedes related information in both this prospectus and the incorporated documents.

All documents filed pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act, after the date of this registration statement and prior to the filing of a post-effective amendment which indicates that all securities offered hereby have been sold or which deregisters all securities then remaining unsold shall be deemed to be incorporated by reference into this registration statement and to be a part hereof from the date of filing of such documents.

Each statement made in this prospectus or any prospectus supplement concerning a document filed as an exhibit to the registration statement is qualified in its entirety by reference to that exhibit for a complete description of its provisions. Any document, and any statement contained in a document, incorporated or deemed to be incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein, or in any other subsequently filed document that also is incorporated or deemed to be incorporated by reference herein, modifies or supersedes such document or statement. Any such document or statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

The documents incorporated by reference in this prospectus may be obtained from us without charge and will be provided to each person, including any beneficial owner, to whom a prospectus is delivered. You may obtain a copy of the documents at no cost by submitting an oral or written request to 21925 W. Field Parkway, Suite 235, Deer Park, Illinois, 60010, or through our telephone number at (847) 787-7361. Further information can be obtained through our website address, www.etonpharma.com. Such additional information contained in our web site is not a part of this prospectus.

This prospectus is part of a registration statement on Form S-3 that we filed with the SEC registering the securities that may be offered and sold hereunder. The registration statement, including exhibits thereto, contains additional relevant information about us and the securities that may be offered and sold hereunder, as permitted by the rules and regulations of the SEC, we have not included in this prospectus. A copy of the registration statement can be obtained at the address set forth below or at the SEC’s website as noted below. You should read the registration statement, including any applicable prospectus supplement, for further information about us and the securities.

We file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document we file with the SEC at the SEC’s Public Reference Room located at 100 F Street, N.E., Washington, D.C. 20549. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC also maintains a website that contains reports, proxy statements, information statements and other information about issuers, like Eton, that file electronically with the SEC. The address of that website is www.sec.gov. The website, and, except as expressly incorporated herein, the information contained therein, is not a part of this prospectus. You may also obtain copies of the documents at prescribed rates by writing to the SEC’s Public Reference Section at 100 F Street, N.E., Washington, D.C. 20549.

	Page
About this Prospectus Supplement	S-ii
Prospectus Supplement Summary	S-1
Special Note Regarding Forward-Looking Statements	S-2
Risk Factors	S-3
Use of Proceeds	S-4
Description of Securities We Are Offering	S-4
Dilution	S-4
Plan of Distribution	S-5
Legal Matters	S-5
Experts	S-5
Incorporation of Certain Information by Reference	S-5

Common stock offered by us		600,000 shares.

Common stock to be outstanding immediately after this offering⁽¹⁾		20,482,486 shares.

Nasdaq Global Market symbol		ETON

Use of proceeds		We intend to use the net proceeds from the sale of common stock offered by this prospectus supplement for general corporate purposes, which may include, but are not limited to, working capital and capital expenditures. See “Use of Proceeds.”

Risk factors		Investing in our common stock involves a high degree of risk. See “Risk Factors.”

	(d)	The description of the company’s securities contained in the Company’s Registration Statement on Form 8-A filed with the SEC on November 8, 2018, pursuant to Section 12(b) of the Exchange Act, including any amendments or reports filed for the purpose of updating such descriptions; and

	(e)	All other reports filed pursuant to Section 13(a) or 15(d) of the Exchange Act, since the end of the fiscal year covered by the Annual Report referred to in (a) above.

About this Prospectus	ii
Prospectus Summary	1
Risk Factors	2
Use of Proceeds	2
Dilution	3
Descriptions of the Securities We May Offer	3
Capital Stock	3
Warrants	5
Debt Securities	7
Units	9
Subscription Rights	9
Plan of Distribution	12
Limitations on Liability and Indemnification of Officers and Directors	13
Legal Matters	14
Experts	14
Incorporation of Certain Information by Reference	14
Where You Can Find Additional Information About Us	15

	●	3,016,878 shares of our common stock issuable upon exercise of outstanding options, of which approximately 803,003 were exercisable at a weighted average exercise price of $3.29 per share, under our 2018 Equity Incentive Plan, as amended, or the Incentive Plan;
	●	100,000 shares of our common stock underlying vested restricted stock awards;
	●	410,936 shares of our common stock reserved for issuance pursuant to the Incentive Plan; and
	●	1,672,335 exercisable warrants for shares of our common stock at an average price of $3.13 per share.

	●	our future financial and operating results;
	●	our intentions, expectations and beliefs regarding anticipated growth, market penetration and trends in our business;
	●	the timing and success of our plan of commercialization;
	●	our ability to successfully develop and clinically test our product candidates;
	●	our ability to file for FDA approval of our product candidates through the 505(b)(2) regulatory pathway;
	●	our ability to obtain FDA approval for any of our product candidates;
	●	our ability to comply with all U.S. and foreign regulations concerning the development, manufacture and sale of our product candidates;
	●	the adequacy of the net proceeds of this offering;
	●	the effects of market conditions on our stock price and operating results;
	●	our ability to maintain, protect and enhance our intellectual property;
	●	the effects of increased competition in our market and our ability to compete effectively;
	●	our plans to use the proceeds from this offering;
	●	costs associated with initiating and defending intellectual property infringement and other claims;
	●	the attraction and retention of qualified employees and key personnel;
	●	future acquisitions of or investments in complementary companies or technologies; and
	●	our ability to comply with evolving legal standards and regulations, particularly concerning the requirements for being a public company.

Public offering price per share			$	3.00
Net tangible book value per share at December 31, 2019	$	0.55
Increase in net tangible book value per share attributable to prior share issuance	$	0.24
Increase in net tangible book value per share attributable to this offering	$	0.06
As-adjusted net tangible book value per share as of March 26, 2020, after giving effect to this offering			$	0.85
Dilution per share to the investor in this offering			$	2.15

	(a)	Annual Report on Form 10-K for the fiscal year ended December 31, 2019, as filed with the SEC on March 5, 2020;

	(b)	Current Reports on Form 8-K, filed with the SEC on January 21, 2020 (with respect to Items 8.01 and 9.01), February 19, 2020 (with respect to Items 8.01 and 9.01), March 17, 2020 (with respect to Items 8.01 and 9.01) and March 18, 2020 (with respect to Item 8.01); and

	(c)	The description of the company’s securities contained in the Company’s Registration Statement on Form 8-A filed with the SEC on November 8, 2018, pursuant to Section 12(b) of the Exchange Act, including any amendments or reports filed for the purpose of updating such description.

	Page No.
About this Prospectus	ii
Prospectus Summary	1
Risk Factors	2
Use of Proceeds	2
Dilution	3
Descriptions of the Securities We May Offer	3
Capital Stock	3
Warrants	5
Debt Securities	7
Units	9
Subscription Rights	9
Plan of Distribution	12
Limitations on Liability and Indemnification of Officers and Directors	13
Legal Matters	14
Experts	14
Incorporation of Certain Information by Reference	14
Where You Can Find Additional Information About Us	15

	●	the net tangible book value per share of our equity securities before and after the offering;

	●	the amount of the increase in such net tangible book value per share attributable to the cash payments made by purchasers in the offering; and

	●	the amount of the immediate dilution from the public offering price which will be absorbed by such purchasers.

	●	shares of our common stock;

	●	shares of our preferred stock;

	●	debt securities;

	●	warrants to purchase any of the securities listed above;

	●	subscription rights to purchase any of the securities listed above; and/or

	●	units consisting of one or more of the foregoing.

	●	the offering price and aggregate number of warrants offered;

	●	if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

	●	if applicable, the date on and after which the warrants and the related securities will be separately transferable;

	●	in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

	●	in the case of warrants to purchase common stock or preferred stock, the number or amount of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at, and currency in which, these shares may be purchased upon such exercise;

	●	the manner of exercise of the warrants, including any cashless exercise rights;

	●	the warrant agreement under which the warrants will be issued;

	●	the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreement and the warrants;

	●	anti-dilution provisions of the warrants, if any;

	●	the terms of any rights to redeem or call the warrants;

	●	any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

	●	the dates on which the right to exercise the warrants will commence and expire or, if the warrants are not continuously exercisable during that period, the specific date or dates on which the warrants will be exercisable;

	●	the manner in which the warrant agreement and warrants may be modified;

	●	the identities of the warrant agent and any calculation or other agent for the warrants;

	●	federal income tax consequences of holding or exercising the warrants;

	●	the terms of the securities issuable upon exercise of the warrants;

	●	any securities exchange or quotation system on which the warrants or any securities deliverable upon exercise of the warrants may be listed or quoted; and

	●	any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

	●	the title;

	●	the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

	●	any limit on the amount that may be issued;

	●	whether or not we will issue the series of debt securities in global form, the terms and who the depositary will be;

	●	the maturity date;

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

	●	whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a U.S. person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

	●	whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;

	●	the terms of the subordination of any series of subordinated debt;

	●	the place where payments will be payable;

	●	restrictions on transfer, sale or other assignment, if any;

	●	our right, if any, to defer payment of interest and the maximum length of any such deferral period;

	●	the date, if any, after which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;

	●	the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holders’ option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

	●	any restrictions on our ability and the ability of our subsidiaries to:

	●	incur additional indebtedness;

	●	issue additional securities;

	●	create liens;

	●	pay dividends and make distributions in respect of our capital stock and the capital stock of our subsidiaries;

	●	redeem capital stock;

	●	place restrictions on our ability and our subsidiaries’ ability to pay dividends, make distributions or transfer assets;

	●	make investments or other restricted payments;

	●	sell or otherwise dispose of assets;

	●	enter into sale-leaseback transactions;

	●	engage in transactions with stockholders and affiliates;

	●	effect a consolidation or merger;

	●	whether the indenture will require us to maintain any interest coverage, fixed charge, cash flow-based, asset-based or other financial ratios;

	●	a discussion of any material United States federal income tax considerations applicable to the debt securities;

	●	information describing any book-entry features;

	●	provisions for a sinking fund purchase or other analogous fund, if any;

	●	the denominations in which we will issue the series of debt securities;

	●	the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars; and

	●	any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, including any additional events of default or covenants provided with respect to the debt securities, and any terms that may be required by us or advisable under applicable laws or regulations.

	●	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;

	●	any unit agreement under which the units will be issued;

	●	any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units; and

	●	whether the units will be issued in fully registered or global form.

	●	the date of determining the stockholders entitled to the rights distribution;

	●	the price, if any, for the subscription rights;

	●	the exercise price payable for the common stock, preferred stock, debt securities, warrants, units or other securities upon the exercise of the subscription right;

	●	the number of subscription rights issued to each stockholder;

	●	the amount of common stock, preferred stock, debt securities, warrants, units or other securities that may be purchased per each subscription right;

	●	any provisions for adjustment of the amount of securities receivable upon exercise of the subscription rights or of the exercise price of the subscription rights;

	●	the extent to which the subscription rights are transferable;

	●	the date on which the right to exercise the subscription rights shall commence, and the date on which the subscription rights shall expire;

	●	the extent to which the subscription rights may include an over-subscription privilege with respect to unsubscribed securities;

	●	the material terms of any standby underwriting or purchase arrangement entered into by us in connection with the offering of subscription rights;

	●	any applicable material U.S. federal income tax considerations; and

	●	any other terms of the subscription rights, including the terms, procedures and limitations relating to the transferability, exchange and exercise of the subscription rights.

	●	prior to that date, the board of directors of the corporation approved either the business combination or the transaction that resulted in the stockholder becoming an interested stockholder;

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

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

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

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

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

	●	subject to limited exceptions, any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder; or

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

	●	the name or names of any underwriters, if, and if required, any dealers or agents;

	●	the purchase price of the securities and the proceeds we will receive from the sale;

	●	any underwriting discounts and other items constituting underwriters’ compensation;

	●	any discounts or concessions allowed or reallowed or paid to dealers; and

	●	any securities exchange or market on which the securities may be listed or traded.

	●	a fixed price or prices, which may be changed;

	●	market prices prevailing at the time of sale;

	●	prices related to such prevailing market prices; or

	●	negotiated prices.

	(a)	Annual Report on Form 10-K for the fiscal year ended December 31, 2018, as filed with the SEC on March 25, 2019;

	(b)	Quarterly Reports on Form 10-Q for the quarter ended March 31, 2019 as filed with the SEC on May 7, 2019, for the quarter ended June 30, 2019, as filed with the SEC on August 6, 2019, and for the quarter ended September 30, 2019, as filed with the SEC on November 14, 2019;

	(c)	Current Reports on Form 8-K, filed with the Commission on January 24, 2019 (with respect to Item 1.01), February 11, 2019 (with respect to Item 1.01), February 19, 2019 (with respect to Item 1.01), March 25, 2019 (with respect to Items 2.02 and 9.01), May 7, 2019 (with respect to Items 2.02 and 9.01), June 12, 2019 (with respect to Item 5.07), June 13, 2019 (with respect to Items 8.01 and 9.01), July 12, 2019 (with respect to Items 8.01 and 9.01), August 1, 2019 (with respect to Items 8.01 and 9.01), August 6, 2019 (with respect to Items 2.02 and 9.01), August 19, 2019 (with respect to Items 8.01 and 9.01), October 22, 2019 (with respect to Items 8.01 and 9.01), and November 14, 2019 (with respect to Items 2.02, 8.01, and 9.01);