As filed with the Securities and Exchange Commission on August 17, 20172020

Registration No. 333-                

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

CONATUS PHARMACEUTICALS INC.Histogen Inc.

(Exact Namename of Registrantregistrant as Specifiedspecified in Its Charter)its charter)

Steven J. Mento, Ph.D.

President and Chief Executive Officer

Conatus Pharmaceuticals Inc.

16745 West Bernardo Drive,10655 Sorrento Valley Road, Suite 200

San Diego, CA 9212792121

(858) 376-2600526-3100

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Richard W. Pascoe

Chief Executive Officer and President

Histogen Inc.

10655 Sorrento Valley Road, Suite 200

San Diego, CA 92121

(858) 526-3100

(Name, address, including zip code, and telephone number, including area code, of agent for service)

CopiesWith a copy to:

Scott N. Wolfe, Esq.Larry W. Nishnick

Cheston J. Larson, Esq.DLA Piper LLP (US)

Matthew T. Bush, Esq.

Latham & Watkins LLP

12670 High Bluff4365 Executive Drive, Suite 1100

San Diego, CA 9213092121

Tel: (858) 523-5400677-1400

Fax: (858) 677-1401

APPROXIMATE DATE OF COMMENCEMENT OF PROPOSED SALE TO THE PUBLIC:Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement.

Registration Statement. If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Formform is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective onupon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ☐

If this Formform is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitionsdefinition of “large accelerated filer,” “accelerated filer,” “smaller reporting company,”company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B)13(a) of the SecuritiesExchange Act.  ☒☐

CALCULATION OF REGISTRATION FEE

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until thisthe registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. These securitiesWe may not be soldsell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor doesthese securities and it seekis not soliciting an offer to buy these securities in any jurisdictionstate where the offer or sale is not permitted.

Subject to Completion,completion, dated August 17, 2017.2020

PROSPECTUS

HISTOGEN INC.

$100,000,000125,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

We may from time to time offer andto sell up to $100.0 million in the aggregateany combination of the securities identified above from time to timedescribed in this prospectus, either individually or in units, in one or more offerings. The aggregate initial offering price of all securities sold under this prospectus will not exceed $125,000,000.

This prospectus provides you with a general description of the securities.

securities we may offer. Each time we offer and sell securities, we will provide specific terms of the securities offered in a supplement to this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. The prospectus that contains specific information about the offeringsupplement and the amounts, prices and terms of the securities. The supplementany related free writing prospectus may also add, update or change information contained in this prospectus with respect to that offering.prospectus. You should carefully read this prospectus, and the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference herein or therein before you invest in any of our securities.

We This prospectus may offer and sell the securities described in this prospectus and any prospectus supplementnot be used to or through one or more underwriters, dealers and agents, or directly to purchasers, or throughconsummate a combination of these methods. If any underwriters, dealers or agents are involved in the sale of any of the securities their names and any applicable purchase price, fee, commission or discount arrangement between or among them will be set forth, or will be calculable from the information set forth, inunless accompanied by the applicable prospectus supplement. See the sections of this prospectus entitled “About this Prospectus” and “Plan of Distribution” for more information. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

INVESTING IN OUR SECURITIES INVOLVES RISKS. SEE THE “RISK FACTORS” ON PAGE 6 OF THIS PROSPECTUS AND ANY SIMILAR SECTION CONTAINED IN THE APPLICABLE PROSPECTUS SUPPLEMENT CONCERNING FACTORS YOU SHOULD CONSIDER BEFORE INVESTING IN OUR SECURITIES.

Our common stock is listed on The Nasdaq GlobalCapital Market under the symbol “CNAT.“HSTO.” On August 16, 2017,14, 2020, the last reported sale price for our common stock was $2.56 per share. There is currently no market for the other securities we may offer. As of August 14, 2020, the aggregate market value of our common stock held by our non-affiliates, as calculated pursuant to the rules of the Securities and Exchange Commission, was $15.7 million. Pursuant to General Instruction I.B.6 of Form S-3, in no event will we sell securities in a public offering with a value exceeding more than one-third of our “public float” (the market value of our common stock held by our non-affiliates) in any 12-month period so long as our public float remains below $75,000,000. We have sold $1,000,000 of securities in reliance on General Instruction I.B.6 of Form S-3 during the 12 calendar months prior to and including the date of this prospectus.

Investing in our securities involves risks. See “Risk Factors” beginning on page 7 and “Item 1A—Risk Factors” of our most recent report on Form 10-K or 10-Q which is incorporated by reference in this prospectus before you invest in our securities.

We may sell these securities directly to investors, through agents designated from time to time or to or through underwriters or dealers. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such underwriters and any applicable commissions or discounts will be set forth in a prospectus supplement. The Nasdaq Global Market was $5.11 per share.price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in a prospectus supplement.

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

The date of this prospectus is                , 2017.2020.

TABLE OF CONTENTSTable of Contents

i

ABOUT THIS PROSPECTUS

This prospectus is a part of a registration statement that we filed with the U.S. Securities and Exchange Commission, or the SEC usingutilizing a “shelf” registration process. By using aUnder this shelf registration statement,process, we may sell any combination of the securities from time to time anddescribed in this prospectus in one or more offerings up to a total dollar amount of $100.0 million as described in this prospectus.$125,000,000. This prospectus provides you with a general description of the securities we may offer. Each time that we offer and sell securities under this shelf registration, we will provide a prospectus supplement to this prospectus that containswill contain specific information about the securities being offered and sold and the specific terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. The prospectus supplement and any related free writing prospectus that we may authorize to be provided to you may also add, update or change information contained in this prospectus with respect toor in any documents that offering. If there is any inconsistency between the information inwe have incorporated by reference into this prospectus. You should read this prospectus, and theany applicable prospectus supplement you should rely on theand any related free writing prospectus, supplement. Before purchasing any securities, you should carefully read both this prospectus and the applicable prospectus supplement, together with the additional information incorporated herein by reference as described under the heading “Where You Can Find More Information; IncorporationAdditional Information.”

You should rely only on the information that we have provided or incorporated by Reference.”

reference in this prospectus, any applicable prospectus supplement and any related free writing prospectus that we may authorize to be provided to you. We have not authorized anyoneany dealer, salesman or other person to provide you withgive any information or to make any representationsrepresentation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectuses preparedprospectus that we may authorize to be provided to you. You must not rely upon any information or representation not contained or incorporated by reference in this prospectus, the accompanying prospectus supplement or on behalf of us or to which we have referred you.related free writing prospectus. We take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We will not make an offer to sell these securities in any jurisdiction where the offer or sale is not permitted.

This prospectus, the accompanying supplement to this prospectus and any related free writing prospectus, if any, do not constitute an offer to sell or the solicitation of an offer to buy any securities other than the registered securities to which they relate, nor do this prospectus, the accompanying supplement to this prospectus or any related free writing prospectus, if any, constitute an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make such offer or solicitation in such jurisdiction. You should not assume that the information appearingcontained in this prospectus, and theany applicable prospectus supplement to thisor any related free writing prospectus is accurate only ason any date subsequent to the date set forth on the front of the date on its respective cover, anddocument or that any information we have incorporated by reference therein is accurate only as ofcorrect on any date subsequent to the date of the document incorporated by reference, unless we indicate otherwise. Our business, financial condition, results of operations and prospects may have changed since those dates. Thiseven though this prospectus, incorporates by reference, and any applicable prospectus supplement or any related free writing prospectus may contain and incorporate by reference, market data and industry statistics and forecasts thatis delivered or the applicable securities are basedsold on independent industry publicationsa later date.

“Histogen,” the Histogen logo and other publicly available information. Although we believe these sourcestrademarks, service marks, and trade names of Histogen are reliable, we do not guarantee the accuracyregistered and unregistered marks of Histogen Inc. Other third-party logos and product/trade names are registered trademarks or completenesstrade names of thistheir respective companies.

ii

SUMMARY

This summary highlights selected information and we have not independently verified this information. Although we are not aware of any misstatements regarding the market and industry data presented infrom this prospectus and the documents incorporated herein by reference these estimates involveand does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, including the risks and uncertainties and are subject to change based on various factors, including thoseof investing in our securities discussed under the heading “Risk Factors” containedbeginning on page 6 of this prospectus, the information incorporated herein by reference, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part. All references in this prospectus to “we,” “us,” “our,” “Histogen,” the “Company” and similar designations refer to Histogen Inc. and its consolidated subsidiaries, unless otherwise indicated or as the context otherwise requires.

Business Overview

Histogen is a therapeutics company focused on developing potential first-in-class restorative therapeutics that ignite the body’s natural process to repair and maintain healthy biological function.

Histogen’s technology is based on the discovery that growing fibroblast cells under simulated embryonic conditions induces them to become multipotent with stem cell like properties. The environment created by Histogen’s proprietary process mimics the conditions within the womb—very low oxygen and suspension. When cultured under these conditions, the fibroblast cells generate biological materials that stimulate a person’s own stem cells to activate and replace/regenerate their damages cells and tissue.

Histogen’s reproducible manufacturing process yields multiple biologic products from a single bioreactor, including cell conditioned medium (CCM), human extracellular matrix (hECM) and hair stimulating complex (HSC), creating a spectrum of products for a variety of markets from one core technology.

1. Human Multipotent Cell Conditioned Media, or CCM: A soluble multipotent CCM that is the starting material for products for skin care and other applications. The liquid complex produced through Histogen’s manufacturing process contains soluble biologicals with a diverse range of embryonic-like proteins. Because the cells produce and secrete these factors while developing the extracellular matrix, or ECM, these proteins are naturally infused into the liquid media in a stabilized form. The CCM contains a diverse mixture of cell-signaling materials, including human growth factors such as Keratinocyte Growth Factor, soluble human ECM proteins such as collagen, and vital proteins which support the epidermal stem cells that renew skin throughout life.

2. Human Extracellular Matrix, or hECM: An insoluble hECM for applications such as orthopedics and soft tissue augmentation, which can be fabricated into a variety of structural or functional forms for tissue engineering and clinical applications. The hECM produced through Histogen’s proprietary process is a novel, all-human, naturally-secreted material. It is most similar to early embryonic structural tissue which provides the framework and signals necessary for cell in-growth and tissue development. By producing similar ECM materials to those that aided in the original formation of these tissues in the embryo, regenerative cells are supported in vitro and have shown potential as therapeutics in vivo.

3. Hair Stimulating Complex, or HSC: A soluble biologic comprised of growth factors involved in the signaling of cells in the body, particularly those factors known to be important in hair formation and the stimulation of resting hair follicles.

Under the hECM and HSC core technology platforms, Histogen has three product candidates in clinical development intended to address what it believes to be underserved, multibillion-dollar global markets:

Additionally, Histogen is developing HST-004, which is a CCM scaffold intended to be administered through an interdiscal injection for spinal disc repair. Early research has shown that HST-004 stimulates stem cells from spinal disc to proliferate and secrete aggrecan and collagen II. HST-004 was shown to reduce inflammation and protease activity and upregulate aggrecan production in an ex vivo spinal disc model.

Histogen has also developed a non-prescription topical skin care ingredient utilizing CCM that harnesses the power of growth factors and other cell signaling molecules to support our epidermal stem cells, which renew skin throughout life. The CCM ingredient for skin care currently generates product revenue from Allergan Sales LLC, who formulates the ingredient into their skin care product lines in spas and professional offices.

Corporate Information

We were incorporated under the laws of Delaware under the name Conatus Pharmaceuticals, Inc. as a private company in July 2005. We completed our initial public offering in July 2013. In May 2020, we acquired Histogen Therapeutics, Inc. (formerly known as Histogen Inc.) through its merger with a wholly owned subsidiary of ours, with Histogen Therapeutics surviving as our wholly-owned subsidiary. As part of that transaction, Conatus Pharmaceuticals, Inc. changed its name to Histogen Inc. Our principal executive offices are located at 10655 Sorrento Valley Road, Suite 200, San Diego, CA 92121 and our telephone number is (858) 526-3100. Our website is www.histogen.com. Information contained on, or that can be accessed through, our website is not incorporated by reference into this prospectus, and you should not consider information on our website to be part of this prospectus. We have included our website address as an inactive textual reference only.

Securities We May Offer

We may offer shares of our common stock and preferred stock, various series of debt securities and warrants to purchase any of such securities, either individually or in units, from time to time under this prospectus, together with any applicable prospectus supplement and related free writing prospectus, at prices and on terms to be determined by market conditions at the time of offering. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

A prospectus supplement and any related free writing prospectus and under similar headings in other documents that are incorporated by reference into this prospectus. Accordingly, investors should not place undue reliance on this information.

When we refermay authorize to “Conatus,” “we,” “our,” “us” and the “Company”be provided to you may also add, update or change information contained in this prospectus or in documents we mean Conatus Pharmaceuticals Inc., unless otherwise specified. Whenhave incorporated by reference. However, no prospectus supplement or free writing prospectus will offer a security that is not registered and described in this prospectus at the time of the effectiveness of the registration statement of which this prospectus is a part.

We may sell the securities directly to or through underwriters, dealers or agents. We, and our underwriters or agents, reserve the right to accept or reject all or part of any proposed purchase of securities. If we referdo offer securities through underwriters or agents, we will include in the applicable prospectus supplement:

Common Stock

We may offer shares of our common stock, par value $0.0001 per share, either alone or underlying other registered securities convertible into or exercisable for our common stock. Holders of our common stock are entitled to dividends as our board of directors may declare from time to time out of legally available funds, subject to the preferential rights of the holders of any shares of our preferred stock that are outstanding or that we meanmay issue in the future. Currently, we do not pay any dividends and we do not have any issued and outstanding preferred stock. Each holder of our common stock is entitled to one vote per share. In this prospectus, we provide a general description of, among other things, our dividend policy and the rights and restrictions that apply to holders of our common stock. Our common stock is described in greater detail in this prospectus under “Description of Capital Stock - Common Stock.”

Preferred Stock

We may issue shares of preferred stock in one or more classes or series. Our board of directors or a committee designated by our board of directors will determine the dividend, voting and conversion rights and other provisions at the time of sale. The particular terms of each class or series of preferred stock, including redemption privileges, liquidation preferences, voting rights, dividend rights and/or conversion rights, will be

more fully described in the applicable prospectus supplement relating to the preferred stock offered thereby. Our preferred stock is described in greater detail in this prospectus under “Description of Capital Stock—Preferred Stock.”

Debt Securities

We may offer debt securities from time to time, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. The senior debt securities will rank equally with any other unsubordinated debt that we may have and may be secured or unsecured. The subordinated debt securities will be subordinate and junior in right of payment, to the extent and in the manner described in the instrument governing the debt, to all or some portion of our indebtedness. Any convertible debt securities that we issue will be convertible into or exchangeable for our common stock or other securities of ours. Conversion may be mandatory or at the holder’s option and would be at prescribed conversion rates.

The debt securities will be issued under one or more documents called indentures, which are contracts between us and a trustee for the holders of the applicabledebt securities. In this prospectus, we have summarized certain general features of the debt securities under “Description of Debt Securities.” We urge you, however, to read the prospectus supplements and any free writing prospectus that we may authorize to be provided to you related to the series of securities.

We use our registered trademark, CONATUS PHARMACEUTICALS, in this prospectus. This prospectus also includes trademarks, tradenames and service marksdebt securities being offered, as well as the complete indentures that are the property of other organizations. Solely for convenience, trademarks and tradenames referred to in this prospectus appear without the^® and ™ symbols, but those references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or that the applicable owner will not assert its rights, to these trademarks and tradenames.

WHERE YOU CAN FIND MORE INFORMATION; INCORPORATION BY REFERENCE

Available Information

We file reports, proxy statements and other information with the SEC. Information filed with the SEC by us can be inspected and copied at the Public Reference Room maintained by the SEC at 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of this information by mail from the Public Reference Room of the SEC at prescribed rates. Further information on the operation of the SEC’s Public Reference Room in Washington, D.C. can be obtained by calling the SEC at 1-800-SEC-0330. The SEC also maintains a web site that contains reports, proxy and information statements and other information about issuers, such as us, who file electronically with the SEC. The address of that website ishttp://www.sec.gov.

Our web site address is www.conatuspharma.com. The information on our web site, however, is not, and should not be deemed to be, a part of this prospectus.

This prospectus and any prospectus supplement are part of a registration statement that we filed with the SEC and do not contain all of the information in the registration statement. The full registration statement may be obtained from the SEC or us, as provided below. Forms of the indenture and other documents establishing the terms of the offered securities are or may bedebt securities. Forms of indentures have been filed as exhibits to the registration statement. Statements instatement of which this prospectus or any prospectus supplement about these documents are summariesis a part, and each statement is qualified in all respectssupplemental indentures and forms of debt securities containing the terms of debt securities being offered will be incorporated by reference to the document to which it refers. You should refer to the actual documents for a more complete description of the relevant matters. You may inspect a copy ofinto the registration statement at the SEC’s Public Reference Room in Washington, D.C. or through the SEC’s website, as provided above.

Incorporation by Reference

The SEC’s rules allow us to “incorporate by reference” information intoof which this prospectus which means thatis a part from reports we can disclose important information to you by referring you to another document filed separatelyfile with the SEC.

Warrants

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

The informationwarrants will be evidenced by warrant certificates issued under one or more warrant agreements, which are contracts between us and an agent for the holders of the warrants. In this prospectus, we have summarized certain general features of the warrants under “Description of Warrants.” We urge you, however, to read the prospectus supplements and any free writing prospectus that we may authorize to be provided to you related to the series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. Specific warrant agreements will contain additional important terms and provisions and will be incorporated by reference is deemedas an exhibit to the registration statement which includes this prospectus.

Units

We may offer units consisting of common stock, preferred stock, debt securities and/or warrants to purchase any of such securities in one or more series. In this prospectus, we have summarized certain general features of the units under “Description of Units.” We urge you, however, to read the prospectus supplements and any free writing prospectus that we may authorize to be partprovided to you related to the series of units being offered, as well as the unit agreements that contain the terms of the units. We will file as exhibits to the registration statement of which this prospectus and subsequent informationis a part, or will incorporate by reference from a current report on Form 8-K that we file with the SEC, the form of unit agreement and any supplemental agreements that describe the terms of the series of units we are offering before the issuance of the related series of units.

We will automatically updateevidence each series of units by unit certificates that we will issue under a separate agreement. We will enter into the unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and supersedeaddress of the unit agent in the applicable prospectus supplement relating to a particular series of units.

SELECTED FINANCIAL DATA

On May 26, 2020, pursuant to the Agreement and Plan of Merger and Reorganization, dated as of January 28, 2020 (the “Merger Agreement”), by and among Histogen Inc. (f/k/a Conatus Pharmaceuticals Inc.) (the “Company”), Histogen Therapeutics Inc. (f/k/a Histogen Inc.), a Delaware corporation (“Private Histogen”), and Chinook Merger Sub, Inc., a Delaware corporation and wholly-owned subsidiary of the Company (“Merger Sub”), Merger Sub merged with and into Private Histogen, with Private Histogen becoming a wholly-owned subsidiary of the Company (the “Merger”). On May 26, 2020, in connection with the closing of the Merger, the Company effected a one-for-ten reverse stock split of its common stock (the “Reverse Stock Split”).

The following selected financial data has been derived from the Company’s (f/k/a Conatus Pharmaceuticals Inc.) audited financial statements included in the Company’s (f/k/a Conatus Pharmaceuticals Inc.) Annual Report on Form 10-K filed with the SEC on March 11, 2020, and the Company’s (f/k/a Conatus Pharmaceutical Inc.’s) unaudited financial statements included in the Quarterly Report on Form 10-Q filed with the SEC on May 1, 2020, as adjusted to reflect the Reverse Stock Split for all periods presented. As a result of the Merger, the Company’s historical results are not indicative of the results that information. Any statement containedmay be expected in the future and results of interim periods are not indicative of the results for the entire year.

As further described in the Company’s Form 10-Q for the quarter ended June 30, 2020, the Merger was accounted for as a previously filed documentreverse asset acquisition in accordance with generally accepted accounting principles in the United States of America (“GAAP”). Under this method of accounting, Private Histogen was deemed to be the accounting acquirer for financial reporting purposes. As a result, as of the closing date of the Merger, as reflected in the Form 10-Q for the quarter ended June 30, 2020, the net assets of the Company were recorded at their acquisition-date relative fair values in the condensed consolidated financial statements of the Company and the reported operating results prior to the Merger are those of Private Histogen as included in such 10-Q. Please refer to the Form 10-Q for the quarter ended June 30, 2020 for additional information.

RISK FACTORS

Investment in our securities involves risks. Prior to making a decision about investing in our securities, you should consider carefully all of the information included and incorporated by reference will beor deemed to be modified or superseded for purposes of this prospectus to the extent that a statement containedincorporated by reference in this prospectus modifies or replaces that statement.

We incorporatethe applicable prospectus supplement, including the risk factors incorporated by reference our documents listed below and any future filings made by us with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, which we refer to as the “Exchange Act” in this prospectus, between the date of this prospectus and the termination of the offering of the securities described in this prospectus. We are not, however, incorporating by reference any documents or portions thereof, whether specifically listed below or filed in the future, that are not deemed “filed” with the SEC, including our Compensation Committee report and performance graph or any information furnished pursuant to Items 2.02 or 7.01 of Form 8-K or related exhibits furnished pursuant to Item 9.01 of Form 8-K.

This prospectus and any accompanying prospectus supplement incorporate by reference the documents set forth below that have previously been filed with the SEC:

Allother 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 the initial registration statementthis prospectus and prior to the effectiveness of the registration statement, but excluding any information furnished to, rather than filed with, the SEC, will also bethat are incorporated by reference into thisherein or in the applicable prospectus and deemed to besupplement. Each of these risk factors could have a material adverse effect on our business, results of operations, financial position or cash flows, which may result in the loss of all or part of thisyour investment. The risks and uncertainties we have described are not the only ones we face. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our operations.

SPECIAL NOTE REGARDING FORWARD-LOOKING INFORMATION

This prospectus from the date of the filing of such reports and documents.

You may request a free copy of any of the documents incorporated herein by reference contain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements are based on our management’s current beliefs, expectations and assumptions about future events, conditions and results and on information currently available to us. Discussions containing these forward-looking statements may be found, among other places, in this prospectus (other than exhibits, unless they are specificallythe Sections entitled “Business,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” incorporated by reference in the documents) by writing or telephoning us at the following address:

Conatus Pharmaceuticals Inc.

Attn: Corporate Secretary

16745 West Bernardo Drive, Suite 200

San Diego, California 92127

(858) 376-2600

Exhibits to the filings will not be sent, however, unless those exhibits have specifically been incorporated by reference in this prospectus and any accompanying prospectus supplement.

THE COMPANY

We are a biotechnology company focused on the development and commercialization of novel medicines to treat liver disease. We are developing emricasan, a first-in-class, orally active pan-caspase protease inhibitor, for the treatment of patients with chronic liver disease. Emricasan is designed to reduce the activities of human caspases, which are enzymes that mediate inflammation and apoptosis. We believe that by reducing the activity of these enzymes, caspase inhibitors have the potential to interrupt the progression of a variety of diseases.

We plan to continue advancing toward initial registration of emricasan for patients with cirrhosis due to nonalcoholic steatohepatitis, or NASH, with parallel development toward registration of emricasan for patients with NASH fibrosis. Our current clinical program for emricasan includes the following randomized, double-blind, placebo-controlled Phase 2b clinical trials:

In May 2017, Novartis Pharma AG, or Novartis, exercised its option under the Option, Collaboration and License Agreement, or the Collaboration Agreement, we entered into with Novartis in December 2016. Pursuant to such exercise, we granted Novartis an exclusive, worldwide license to our intellectual property rights relating to emricasan to collaborate with us and develop and commercialize emricasan products, containing emricasan either as a single active ingredient or in combination with other Novartis compounds for liver cirrhosis or liver fibrosis, for the treatment, diagnosis and prevention of disease in all indications in humans. The license became effective upon our receipt of a $7.0 million option exercise payment in July 2017.

Pursuant to the Collaboration Agreement, we are responsible for completing the three ENCORE trials and the POLT-HCV-SVR trial described above. We and Novartis will share the costs of these four Phase 2b trials equally. Novartis is responsible for 100% of certain expenses for required registration-supportive nonclinical activities. Novartis is also responsible for the development of emricasan beyond the four Phase 2b trials described above, including the Phase 3 development of emricasan single agent products and all development for emricasan combination products, and Novartis has agreed to use commercially reasonable efforts to develop and commercialize emricasan products. A joint steering committee comprised of representatives from our company and Novartis oversees the collaboration, development and commercialization of emricasan products.

Under the Collaboration Agreement, Novartis paid us an upfront payment of $50.0 million and an option exercise payment of $7.0 million. In addition, we are eligible to receive up to an aggregate of $650.0 million in milestone payments, as well as royalties.

We also plan to expand our development pipeline by developing our existing preclinical product candidates, developing new product candidates, or purchasing or in-licensing product candidates. In addition to liver disease,

we may pursue the development of product candidates in other disease areas. In June 2017, the U.S. Food and Drug Administration granted Orphan Drug Designation to our preclinical product candidate IDN-7314, a pan-caspase inhibitor, for the treatment of primary sclerosing cholangitis, a disease affecting bile ducts in the liver, which can lead to cirrhosis and liver failure. We believe the Orphan Drug Designation provides a potential opportunity to address an important unmet medical need and expand our development pipeline beyond emricasan. We will continue to evaluate the potential of IDN-7314 as a product candidate, along with other product candidate opportunities, and we plan to announce initial pipeline expansion plans later in 2017.

We were incorporated under the laws of the state of Delaware in 2005. Our principal executive offices are located at 16745 West Bernardo Drive, Suite 200, San Diego, California 92127, and our telephone number is (858) 376-2600.

RISK FACTORS

Investment in any securities offered pursuant to this prospectus and the applicable prospectus supplement involves risks. You should carefully consider the risk factors incorporated by reference to our most recent Annual Report on Form 10-K and any subsequentin our Quarterly Reports on Form 10-Q, or Current Reports as well as any amendments thereto, and our prospectus dated April 1, 2020, filed with the Securities and Exchange Commission pursuant to Rule 424(b) under the Securities Act, relating to the Registration Statement on Form 8-K we file afterS-4, as amended (File No. 333-236332), each filed with the date of this prospectus, and all other information contained or incorporated by reference into this prospectus, as updated by our subsequent filings under the Exchange Act, and the risk factors and other information contained in the applicable prospectus supplement before acquiring any of such securities. The occurrence of any of these risks might cause you to lose all or part of your investment in the offered securities.

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference herein contain forward-looking statements. All statements other than statements of historical facts contained in this prospectus and the documents incorporated by reference herein are forward-looking statements, including statements regarding our future results of operations and financial position, business strategy, prospective products, product approvals, research and development costs, timing and likelihood of success, plans and objectives of management for future operations and future results of anticipated products. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by theforward-looking statements.SEC. This prospectus and the documents incorporated by reference herein also contain estimates and other statistical data made by independent parties and by us relating to market size and growth and other data about our industry. This data involves a number of assumptions and limitations, and you are cautioned not to give undue weight to such estimates. In addition, projections, assumptions and estimates of our future performance and the future performance of the markets in which we operate are necessarily subject to a high degree of uncertainty and risk.

In some cases, you canAll statements, other than statements of historical fact, included or incorporated herein regarding our strategy, future operations, financial position, future revenues, projected costs, plans, prospects and objectives are forward-looking statements. Words such as “expect,” “anticipate,” “intend,” “plan,” “believe,” “seek,” “estimate,” “think,” “may,” “could,” “will,” “would,” “should,” “continue,” “potential,” “likely,” “opportunity” and similar expressions or variations of such words are intended to identify forward-looking statements, by terms such as “may,” “will,” “should,” “expect,” “plan,” “anticipate,” “could,” “intend,” “target,” “project,” “contemplates,” “believes,” “estimates,” “predicts,” “potential”but are not the exclusive means of identifying forward-looking statements. These forward-looking statements include, but are not limited to, statements about:

Such statements are based on currently available operating, financial and competitive information and are subject to various risks, uncertainties and assumptions that could cause actual results to differ materially from those anticipated or implied in our forward-looking statements due to a number of factors including, but not limited to, those set forth above under the section entitled “Risk Factors” in this prospectus and the documents incorporated by reference herein are only predictions. We have basedany accompanying prospectus supplement. Given these forward-looking statements largely on our current expectations and projections about future events and financial trends that we believe may affect our business, financial condition and results of operations. These forward-looking statements speak only as of the date of this prospectus and are subject to a number of risks, uncertainties and assumptions,other factors, many of which we discuss in greater detail in the documents incorporated by reference herein, including under the heading “Risk Factors” and elsewhere in this prospectus. The events and circumstances reflected inare beyond our forward-looking statements may not be achieved or occur and actual results could differ materially from those projected in the forward-looking statements. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Given these risks and uncertainties,control, you should not place undue reliance on these forward-looking statements. Except as required by applicable law, we do not planassume no obligation to update these forward-looking statements publicly, update or to revise any forward-looking statements contained into reflect events or developments occurring after the date of this prospectus, or the documents incorporated by reference herein, whether as a result of anyeven if new information future events, changed circumstances or otherwise. For all forward-looking statements, we claim the protection of the safe harbor for forward-looking statements containedbecomes available in the Private Securities Litigation Reform Act of 1995.future.

USE OF PROCEEDS

WeExcept as described in any applicable prospectus supplement and in any free writing prospectuses in connection with a specific offering, we currently intend to use the net proceeds from the sale of the securities offered hereby for general corporate purposes and working capital, which include, but are not limited to, the funding of clinical development of and pursuing regulatory approval for our product candidates, and general and administrative expenses. We may also use a portion of the net proceeds to acquire or invest in technologies, product candidates, products and/or businesses that we believe will enhance the value of our company, although we have no current commitments or agreements with respect to any such transactions as of the date of this prospectus. We have not determined the amount of net proceeds to be used specifically for the foregoing purposes. As a result, our management will have broad discretion in the allocation of the net proceeds and investors will be relying on the judgment of our management regarding the application of the proceeds of any sale of the securities. If a material part of the net proceeds is to be used to repay indebtedness, we will set forth the interest rate and maturity of such indebtedness in the applicablea prospectus supplement. Pending use of the net proceeds, we intend to invest the proceeds in interest-bearing, marketable securities. Pending these uses, we intend to invest the net proceeds in investment-grade, interest-bearing securities.

DIVIDEND POLICY

We have never declared or paid any cash dividends on our capital stock. We currently anticipate that we will retain future earnings, if any, for the development, operation and expansion of our businesscommon stock and do not anticipate declaring or payingexpect to pay any cash dividends for the foreseeable future. We currently intend to retain any future earnings to fund the operation, development and expansion of our business. Any future determination related to our dividend policypay dividends will be made at the sole discretion of our boardBoard of directors after consideringDirectors and will depend upon a number of factors, including our financial condition, results of operations, capital requirements, businessfinancial condition, future prospects, contractual arrangements, restrictions imposed by applicable law, any limitations on payments of dividends present in future debt arrangements, and other factors the boardour Board of directors deems relevant, and subject to the restrictions contained in any future financing instruments.Directors may deem relevant.

RATIODESCRIPTION OF EARNINGS TO FIXED CHARGESSECURITIES WE MAY OFFER

The following table sets forth the historical ratios of earnings to fixed charges for Conatus for the periods indicated.

For purposes of calculating the ratio of earnings to fixed charges, earnings represent net income (loss) before provision for income taxes plus fixed charges. Fixed charges consist of interest expense, the remeasurement of convertible debt to fair value, and an estimate of the interest factor inherent in our operating leases. The portion of total rental expense that represents the interest factor is estimated to be 4%.

For the periods indicated above, we had no outstandingWe may offer shares of preferredour common stock with required dividend payments. Therefore, the ratios of earnings to combined fixed charges and preferred stock, dividends are identicalvarious series of debt securities and warrants to purchase any of such securities, either individually or in units, from time to time under this prospectus, together with any applicable prospectus supplement and related free writing prospectus, at prices and on terms to be determined by market conditions at the ratios presented intime of offering. This prospectus provides you with a general description of the tables above.securities we may offer. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities. We may offer up to $125,000,000 of securities under this prospectus.

DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock, is not completetogether with any additional information we include in any applicable prospectus supplements or any free writing prospectuses that we may authorize to be delivered to you, summarizes the material terms and may not contain all the information you should consider before investing inprovisions of our capital stock. This descriptionstock that we may offer under this prospectus. While the terms we have summarized below will apply generally to any future capital stock that we may offer, we will describe the particular terms of any class or series of these securities in more detail in the applicable prospectus supplement or free writing prospectus. For the complete terms of our capital stock, please refer to our certificate of incorporation and our bylaws that are incorporated by reference into the registration statement of which this prospectus is summarized from,a part or may be incorporated by reference in this prospectus or any prospectus supplement. The terms of these securities may also be affected by the Delaware General Corporation Law, or the DGCL. The summary below and that contained in any prospectus supplement or free writing prospectus are qualified in itstheir entirety by reference to our amended and restated certificate of incorporation which has been publicly filed with the SEC. See “Where You Can Find More Information; Incorporation by Reference.”and our bylaws.

Our authorized capital stock consists of:

Common Stock

AsThe holders of June 30, 2017, there were 29,994,275 shares of our common stock outstanding and held of record by 27 stockholders. Under the terms of our amended and restated certificate of incorporation, holders of our common stock are entitled to one vote for eachper share held on all matters submitted to a vote ofbe voted upon by our stockholders including the election of directors, and do not havethere are no cumulative voting rights. Accordingly, the holders of a majority of the outstanding shares of common stock entitled to vote in any election of directors can elect all of the directors standing for election, if they so choose, other than any directors that holders of any preferred stock we may issue may be entitled to elect. Subject to preferences that may be applicable to any then outstanding preferred stock, the holders of shares of our common stock are entitled to receive ratably thoseany dividends if any, asthat may be declared from time to time by theour board of directors out of funds legally available funds.for that purpose. In the event of our liquidation, dissolution or winding up, the holders of shares of our common stock will beare entitled to share ratably in theall assets legally available for distribution to stockholdersremaining after the payment of or provision for all of our debts and other liabilities, subject to the prior distribution rights of any preferred stock then outstanding. Holders ofOur common stock havehas no preemptive or conversion rights or other subscription rights and thererights. There are no redemption or sinking fundsfund provisions applicable to theour common stock. All outstanding shares of

Our common stock are duly authorized, validly issued, fully paid and nonassessable.is listed on The rights, preferences and privileges of holders of common stock are subject to and may be adversely affected byNasdaq Capital Market under the rights of the holders of shares of any series of preferred stock that we may designate and issue in the future.symbol “HSTO.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is American Stock Transfer & Trust Company, LLC. Its address is 6201 15th Avenue, Brooklyn, NY 11219.

Preferred Stock

We currently have no outstanding sharesThe following description of our preferred stock. Understock and the description of the terms of any particular series of our preferred stock that we choose to issue hereunder are not complete. These descriptions are qualified in their entirety by reference to our amended and restated certificate of incorporation and the certificate of designation, if and when adopted by our board of directors, relating to that series. The rights, preferences, privileges and restrictions of the preferred stock of each series will be fixed by the certificate of designation relating to that series.

We currently have no shares of preferred stock outstanding. Our board of directors has the authority, without further action by ourthe stockholders, to issue up to 10,000,000 shares of preferred stock in one or more series to establish from time to time the number of shares to be included in each such series,and to fix the dividend, voting and other rights, preferences, and privileges of the shares of each wholly unissued series and any qualifications, limitations or restrictions thereon, and to increase or decrease the number of shares of any such series, but not below the number of shares of such series then outstanding. Prior to the issuance of shares of each series, the board of directors is required by the General Corporation Law of the State of Delaware, or the DGCL, and our amended and restated certificate of incorporation to adopt resolutions and file a certificate of designation with the Secretary of State of the State of Delaware. The certificate of designation fixes for each class or series the designations, powers, preferences, rights, qualifications, limitations and restrictions including dividendgranted to or imposed upon the preferred stock. Any or all of these rights conversionmay be greater than the rights redemption privileges and liquidation preferences.of our common stock.

Our board of directors, may authorize the issuance ofwithout stockholder approval, can issue preferred

stock with voting, conversion or conversionother rights that could adverselynegatively affect the voting power or other rights of the holders of the common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and other corporate purposes, could, among other things, have the effect of delaying, deferring or preventing a change in our control and may adversely affect the market price of the common stock and the voting and other rights of the holders of our common stock.

We will describe Preferred stock could thus be issued quickly with terms calculated to delay or prevent a change in a prospectus supplement relatingcontrol of us or make it more difficult to remove our management. Additionally, the class or seriesissuance of preferred stock being offeredmay have the effect of decreasing the market price of our common stock.

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

Unless we specify otherwise in the applicable prospectus supplement, the preferred stock will rank, relating to dividends and upon our liquidation, dissolution or winding up:

The term equity securities does not include convertible debt securities.

Warrants

As of June 30, 2017, there were outstanding warrants to purchase 149,704 shares of our common stock. The warrants contain customary anti-dilution and net issuance provisions and are not callable by us.

Registration Rights

As of June 30, 2017, holders of 2,015,847 shares of our common stock, which includes 35,096 shares of common stock issuable upon the exercise of warrants,conditions, if any, for conversion or their transferees will be entitled to the following rights with respect to the registration of such shares for public resale under the Securities Act of 1933, as amended, or the Securities Act, pursuant to an investor rights agreement by and among us and certain of our stockholders. The registrationexchange of shares of commonany other class or classes of our capital stock as a resultor any series of any other class or classes, or of any other series of the followingsame class, or any other securities or assets, including the price or the rate of conversion or exchange and the method, if any, of adjustment;

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

Our amended and restated bylaws provide that a special meeting of our stockholders may be called only by our board of directors, chairperson of the directors standing for election, if they choose,board, chief executive officer or president (in the absence of a chief executive officer), but such special meetings may not be called by any other than any directors that holdersperson or persons. Because our stockholders do not have the right to call a special meeting, a stockholder could not force stockholder consideration of a proposal over the opposition of our preferredboard of directors by calling a special meeting of stockholders prior to such time as a majority of our board of directors, the chairperson of our board of directors, the president or the chief executive officer believed the matter should be considered or until the next annual meeting, provided that the requestor met the notice requirements. The restriction on the ability of stockholders to call a special meeting means that a proposal to replace our board of directors also could be delayed until the next annual meeting.

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

Anti-Takeover Effects of Delaware Anti-Takeover StatuteLaw

We are subject to the provisions of Section 203 of the Delaware General Corporation Law, which prohibits persons deemed toDGCL (“Section 203”). Under Section 203, we would generally be “interested stockholders”prohibited from engaging in any business combination with any interested stockholder for a “business combination” with a publicly held Delaware corporation forperiod of three years following the date thesetime that this stockholder became an interested stockholder unless:

Under Section 203, a “business combination” includes:

In general, Section 203 defines an interested stockholder was, approved in a prescribed manneras an entity or another prescribed exception applies. Generally, an “interested stockholder” is a person who, together with affiliates and associates, owns, or within three years prior to the determination of interested stockholder status did own,beneficially owning 15% or more of a corporation’sthe outstanding voting stock. Generally, a “business combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. The existence of this provision may have an anti-takeover effect with respect to transactions not approved in advance by the board of directors.

Amendment of Charter Provisions

The amendment of any of the above provisions, except for the provision making it possible for our board of directors to issue preferred stock, would require approvalcorporation and any entity or person affiliated with or controlling or controlled by holders of at least two-thirds of the total voting power of all of our outstanding voting stock.such entity or person.

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

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement,supplements or free writing prospectuses, summarizes certain generalthe material terms and provisions of the debt securities that we may offer under this prospectus. WhenWe may issue debt securities, in one or more series, as either senior or subordinated debt or as senior or subordinated convertible debt. While the terms we have summarized below will apply generally to any future debt securities we may offer under this prospectus, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement or free writing prospectus. The terms of any debt securities we offer under a prospectus supplement may differ from the terms we describe below. However, no prospectus supplement shall fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness. As of the date of this prospectus, we have no outstanding registered debt securities. Unless the context requires otherwise, whenever we refer to sellthe “indentures,” we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.

We will issue any senior debt securities under the senior indenture that we will describeenter into with the specifictrustee named in the senior indenture. We will issue any subordinated debt securities under the subordinated indenture and any supplemental indentures that we will enter into with the trustee named in the subordinated indenture. We have filed forms of these documents as exhibits to the registration statement, of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the series in a supplementdebt securities being offered will be filed as exhibits to this prospectus. We will also indicate in the supplement to what extent the general terms and provisions described inregistration statement of which this prospectus applyis a part or will be incorporated by reference from reports that we file with the SEC.

The indentures will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We use the term “trustee” to refer to either the trustee under the senior indenture or the trustee under the subordinated indenture, as applicable.

The following summaries of material provisions of the senior debt securities, the subordinated debt securities and the indentures are subject to, and qualified in their entirety by reference to, all of the provisions of the indenture and any supplemental indentures applicable to a particular series of debt securities. ToWe urge you to read the extent the information contained in theapplicable prospectus supplement differs from this summary description, you should rely on the information in the prospectus supplement.

We may issue debt securities either separately, or together with, or upon the conversion or exercise of or in exchange for, other securities described in this prospectus. Debt securities may be our senior, senior subordinated or subordinated obligationssupplements and unless otherwise specified in a supplementany related free writing prospectuses related to this prospectus, the debt securities will be our direct, unsecured obligations andthat we may be issued in one or more series.

The debt securities will be issuedoffer under an indenture between us and a trustee named inthis prospectus, as well as the prospectus supplement. We have summarized select portionscomplete indentures that contain the terms of the indenture below. The summary is not complete. The formdebt securities. Except as we may otherwise indicate, the terms of the senior indenture has been filed as an exhibit toand the registration statement and you should read thesubordinated indenture for provisions that may be important to you. In the summary below, we have included references to the section numbers of the indenture so that you can easily locate these provisions. Capitalized terms used in the summary and not defined herein have the meanings specified in the indenture.are identical.

General

The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and set forth or determined in the manner provided in a resolution of our board of directors, in an officer’sofficers’ certificate or by a supplemental indenture. (Section 2.2) The particularDebt securities may be issued in separate series without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the debt securities of any series. We will describe in the applicable prospectus supplement the terms of each series of debt securities will be described in a prospectus supplement relating to such series (including any pricing supplement or term sheet).

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium, or at a discount. (Section 2.1) We will set forth in a prospectus supplement (including any pricing supplement or term sheet) relating to any series of debt securities being offered, including:

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

If we denominate the purchase price of any of the debt securities in a foreign currency or currencies or a foreign currency unit or units, or if the principal of, and premium, if any, and interest on, any series of debt securities is payable in a foreign currency or currencies or a foreign currency unit or units, we will provide you with information on the restrictions, elections, general tax considerations, specific terms and other information with respect to that issue of debt securities and such foreign currency or currencies or foreign currency unit or units in the applicable prospectus supplement.

Transfer and Exchange

Each debt security will be represented by either one or more global securities registered in the name of The Depository Trust Company, DTC or the Depositary, or a nominee of the Depositary (we will refer to any debt security represented by a global debt security as a “book-entry debt security”), or a certificate issued in definitive registered form (we will refer to any debt security represented by a certificated security as a “certificated debt security”) as set forth in the applicable prospectus supplement. Except as set forth under the heading “Global Debt Securities and Book-Entry System” below, book-entry debt securities will not be issuable in certificated form.

Certificated Debt Securities. You may transfer or exchange certificated debt securities at any office we maintain for this purpose in accordance with the terms of the indenture. (Section 2.4) No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange. (Section 2.7)

You may effect the transfer of certificated debt securities and the right to receive the principal of, premium and interest on certificated debt securities only by surrendering the certificate representing those certificated debt securities and either reissuance by us or the trustee of the certificate to the new holderadvisable under applicable laws or the issuance by usregulations.

We will describe in each applicable prospectus supplement any additional events of default relating to the relevant series of debt securities.

If an event of default with respect to debt securities of any series occurs and is continuing, other than an event of default specified in the last bullet point above, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series, as providedby notice to us in writing, and to the indenture;

These limitations do not apply to institute the proceeding within 60 days. (Section 6.7)

any series of debt securities that we may issue or otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may only make the following changes with the consent of each holder of any outstanding debt securities affected:

Discharge

Each indenture provides that, subject to the terms of the indenture and any limitation otherwise provided in the prospectus supplement applicable to a particular series of debt securities, we may elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:

In order to exercise our rights to be discharged, we must deposit with the trustee money or government obligations sufficient to pay all the principal of, and any premium and interest on, the debt securities of the series on the dates payments are due.

Form, Exchange and Transfer

We will issue the debt securities of each series only in fully registered form without coupons and, unless we otherwise specify in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple thereof. The indentures provide that we may issue debt securities of a series in temporary or permanent global form and as book-entry securities that will be deposited with, or on behalf of, The Depository Trust Company or another depositary named by us and identified in a prospectus supplement with respect to that series. See “Legal Ownership of Securities” below for a further description of the terms relating to any book-entry securities.

At the option of the holder, subject to the terms of the indentures and the limitations applicable to global securities described in the applicable prospectus supplement, the holder of the debt securities of any series can exchange the debt securities for other debt securities of the same series, in any authorized denomination and of like tenor and aggregate principal amount.

Subject to the terms of the indentures and the limitations applicable to global securities set forth in the applicable prospectus supplement, holders of the debt securities may present the debt securities for exchange or for registration of transfer, duly endorsed or with the form of transfer endorsed thereon duly executed if so

required by us or the security registrar, at the office of the security registrar or at the office of any transfer agent designated by us for this purpose. Unless otherwise provided in the debt securities that the holder presents for transfer or exchange, we will make no service charge for any registration of transfer or exchange, but we may require payment of any taxes or other governmental charges.

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

If we elect to redeem the debt securities of any series, we will not be required to:

Information Concerning the Trustee

The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture and is under no obligation to exercise any of the powers given it by the indentures at the request of any holder of debt securities unless it is offered reasonable security and indemnity against the costs, expenses and liabilities that it might incur. However, upon an event of default under an indenture, the trustee must use the same degree of care as a prudent person would exercise or use in the conduct of his or her own affairs.

Payment and Paying Agents

Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt security payablesecurities on any interest payment date to the person in currency other than that stated inwhose name the debt security;

Ranking Debt Securities

The subordinated debt securities will be unsecured and will be subordinate and junior in priority of payment to certain other indebtedness to the extent described in a prospectus supplement. The subordinated indenture will providedoes not limit the amount of subordinated debt securities that we the trustee and the holders of themay issue. It also does not limit us from issuing any other secured or unsecured debt.

The senior debt securities (by their acceptancewill be unsecured and will rank equally in right of payment to all our other senior unsecured debt. The senior indenture does not limit the debt securities) irrevocably waive, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising outamount of or relating to the indenture, thesenior debt securities or the transactions contemplated thereby.

The indenture will provide that any legal suit, action or proceeding arising out of or based upon the indenture or the transactions contemplated thereby may be instituted in the federal courts of the United States of America located in the City of New York or the courts of the State of New York in each case located in the City of New York, and we, the trustee and the holder of the debt securities (by their acceptance of the debt securities) irrevocably submit to the non-exclusive jurisdiction of such courts in any such suit, action or proceeding. The indenture will further provide that service of any process, summons, notice or document by mail (to the extent allowed under any applicable statute or rule of court) to such party’s address set forth in the indenture will be effective service of process for any suit, action or other proceeding brought in any such court. The indenture will further provide that we the trustee and the holders of the debt securities (by their acceptance of the debt securities) irrevocably and unconditionally waivemay issue. It also does not limit us from issuing any objection to the laying of venue of any suit, actionother secured or other proceeding in the courts specified above and irrevocably and unconditionally waive and agree not to plead or claim any such suit, action or other proceeding has been brought in an inconvenient forum. (Section 10.10)unsecured debt.

DESCRIPTION OF WARRANTS

WeThe following description, together with the additional information we may issueinclude in any applicable prospectus supplements and free writing prospectuses, summarizes the material terms and provisions of the warrants for thethat we may offer under this prospectus, which may consist of warrants to purchase of shares of our common stock, or preferred stock or of debt securities. Wesecurities and may issue warrantsbe issued in one or more series. Warrants may be offered independently or together with othercommon stock, preferred stock or debt securities offered by any prospectus supplement, and the warrants may be attached to or separate from those securities. While the terms we have summarized below will apply generally to any offered securities. Eachwarrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants will be issuedthat we may offer in more detail in the applicable prospectus supplement and any applicable free writing prospectus. The terms of any warrants offered under a separateprospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness.

We will issue the warrants under a warrant agreement that we will enter into with a warrant agent to be entered into between usselected by us. The warrant agent will act solely as an agent of ours in connection with the warrants and will not act as an agent for the investorsholders or beneficial owners of the warrants. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from a current report on Form 8-K that we file with the SEC, the form of warrant agent.agreement, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering before the issuance of the related series of warrants. The following summarysummaries of material provisions of the warrants and the warrant agreements isare subject to, and qualified in itstheir entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to a particular series of warrants. The terms of any warrants offered under a prospectus supplement may differ from the terms described below. We urge you to read the applicable prospectus supplement and any relatedapplicable free writing prospectus related to the particular series of warrants that we sell under this prospectus, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants.

The particularGeneral

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

HoldersBefore exercising their warrants, holders of equity warrants will not be entitled to:have any of the rights of holders of the securities purchasable upon such exercise, including:

Exercise of stockholders for the election of our directors or any other matter; or

DESCRIPTION OF UNITS

We may issue units consisting of any combination of the other types of securities offered under this prospectus in one or more series. We may evidence each series of units by unit certificates that we will issue under a separate agreement. We may enter into unit agreements with a unit agent. Each unit agent will be a bank or trust company that we select. We will indicate the name and address of the unit agent in the applicable prospectus supplement relating to a particular series of units.

The following description, together with the additional information includedwe may include in any applicable prospectus supplement,supplements and free writing prospectuses, summarizes the general featuresmaterial terms and provisions of the units that we may offer under this prospectus. You should readWhile the terms we have summarized below will apply generally to any prospectus supplement and any free writing prospectusunits that we may authorize to be provided to you related tooffer under this prospectus, we will describe the particular terms of any series of units beingin more detail in the applicable prospectus supplement. The terms of any units offered as well as the complete unit agreements that containunder a prospectus supplement may differ from the terms described below. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of the units. Specific unit agreements will contain additional important terms and provisions and weits effectiveness.

We will file as an exhibitexhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from anothera current report on Form 8-K that we file with the SEC, the form of each unit agreement relating to units offered under this prospectus.

If we offer any units, certainthat describes the terms of thatthe series of units we are offering, and any supplemental agreements, before the issuance of the related series of units. The following summaries of material terms and provisions of the units are subject to, and qualified in their entirety by reference to, all the provisions of the unit agreement and any supplemental agreements applicable to a particular series of units. We urge you to read the applicable prospectus supplements related to the particular series of units that we sell under this prospectus, as well as the complete unit agreement and any supplemental agreements that contain the terms of the units.

General

We may issue units comprised of one or more debt securities, shares of common stock, shares of preferred stock and warrants in any combination. Each unit will be describedissued 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. 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.

We will describe in the applicable prospectus supplement including, without limitation, the following, as applicable:

The provisions described in this section, as well as those described under “Description of Capital Stock,” “Description of Debt Securities” and “Description of Warrants” will apply to each unit and to any common stock, preferred stock, debt security or warrant included in each unit, respectively.

Issuance in Series

We may issue units in such amounts and in numerous distinct series as we determine.

Enforceability of Rights by Holders of Units

Each unit agent will act solely as our agent under the applicable unit agreement and will not assume any obligation or relationship of agency or trust with any holder of any unit. A single bank or trust company may act as unit agent for more than one series of units. A unit agent will have no duty or responsibility in case of any default by us under the applicable unit agreement or unit, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a unit may, without the consent of the related unit agent or the holder of any other unit, enforce by appropriate legal action its rights as holder under any security included in the unit.

We, the unit agents and any of their constituent securities.agents may treat the registered holder of any unit certificate as an absolute owner of the units evidenced by that certificate for any purpose and as the person entitled to exercise the rights attaching to the units so requested, despite any notice to the contrary. See “Legal Ownership of Securities.”

GLOBALLEGAL OWNERSHIP OF SECURITIES

Book-Entry, DeliveryWe can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below. We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee or depositary or warrant agent maintain for this purpose as the “holders” of those securities. These persons are the legal holders of the securities. We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and Form

Unless we indicate differentlyinvestors in a prospectus supplement, the securities initially will be issued in book-entry form andor in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global notes or global securities or, collectively, global securities. The global securities will be deposited with, or on behalf of DTC and registered in the name of Cede & Co.,a financial institution that holds them as depositary on behalf of other financial institutions that participate in the nominee of DTC. Unless and until it is exchanged for individual certificates evidencing securities under the limited circumstances described below, a global security may not be transferred except as a whole by the depositary to its nominee or by the nominee to the depositary, or by the depositary or its nominee to a successor depositary or to a nominee of the successor depositary.

DTC has advised us that it is:

DTC holds securities that its participants deposit with DTC. DTC also facilitates the settlement among its participants of securities transactions, such as transfers and pledges, in deposited securities through electronic computerizeddepositary’s book-entry changes in participants’ accounts, thereby eliminating the need for physical movement of securities certificates. “Direct participants” in DTC include securities brokers and dealers, including underwriters, banks, trust companies, clearing corporations and other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, or DTCC. DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all ofsystem. These participating institutions, which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others, which we sometimes referreferred to as indirect participants, that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit forin turn, hold beneficial interests in the securities on DTC’s records. The ownership interestbehalf of themselves or their customers.

Only the actual purchaser ofperson in whose name a security which we sometimes refer tois registered is recognized as a beneficial owner, is in turn recorded on the direct and indirect participants’ records. Beneficial ownersholder of that security. Global securities will not receive written confirmation from DTC of their purchases. However, beneficial owners are expected to receive written confirmations providing details of their transactions, as well as periodic statements of their holdings, from the direct or indirect participants through which they purchased securities. Transfers of ownership interests in global securities are to be accomplished by entries made on the books of participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the global securities, except under the limited circumstances described below.

To facilitate subsequent transfers, all global securities deposited by direct participants with DTC will be registered in the name of DTC’s partnership nominee, Cede & Co.,the depositary or suchits participants. Consequently, for global securities, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary. The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a global security will not own securities directly. Instead, they will own beneficial interests in a global security, through a bank, broker or other namefinancial institution that participates in the depositary’s book-entry system or holds an interest through a participant. As long as the securities are issued in global form, investors will be indirect holders, and not legal holders, of the securities.

Street Name Holders

We may be requestedterminate a global security or issue securities that are not issued in global form. In these cases, investors may choose to hold their securities in their own names or in “street name.” Securities held by an authorized representative of DTC. The deposit of securities with DTC and their registrationinvestor in street name would be registered in the name of Cede & Co.a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we or any applicable trustee or depositary will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we or any such other nomineetrustee or depositary will not changemake all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial ownershipowners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not legal holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee or third party employed by us or a trustee, run only to the legal holders of the securities. DTCWe do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means. This will be the case whether an investor chooses to be an indirect holder of a security or has no knowledgechoice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with its participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the actual beneficial ownersholders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of an indenture, or for other purposes. In such an event, we would seek approval only from the legal holders, and not the indirect holders, of the securities. DTC’s records reflect onlyWhether and how the identity oflegal holders contact the direct participantsindirect holders is up to whose accountsthe legal holders.

Special Considerations for Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form because the securities are credited, which mayrepresented by one or may notmore global securities or in street name, you should check with your own institution to find out:

Global Securities

A global security is a security that represents one or any other number of individual securities only throughheld by a depositary. Generally, all securities represented by the facilities ofsame global securities will have the depositary and its direct and indirect participants. We will maintain an office or agency in the location specified in the prospectus supplement for the applicable securities, where notices and demands in respect of the securities and the indenture may be delivered to us and where certificated securities may be surrendered for payment, registration of transfer or exchange.same terms.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any legal requirements in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities of a particular series are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the securities of such series to be redeemed.

Neither DTC nor Cede & Co. (or such other DTC nominee) will consent or vote with respect to the securities. Under its usual procedures, DTC will mail an omnibus proxy to us as soon as possible after the record date. The omnibus proxy assigns the consenting or voting rights of Cede & Co. to those direct participants to whose accounts the securities of such series are credited on the record date, identified in a listing attached to the omnibus proxy.

So long as securities areEach security issued in book-entry form will be represented by a global security that we issue to, deposit with and register in the name of a financial institution or its nominee that we select. The financial institution that we select for this purpose is called the depositary. Unless we specify otherwise in the applicable prospectus supplement, The Depository Trust Company, New York, New York, known as DTC, will make payments onbe the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise. We describe those securities tosituations below under “- Special Situations When A Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, aswill be the sole registered owner and legal holder of suchall securities represented by wire transfera global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of immediately available funds. an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does. Thus, an investor whose security is represented by a global security will not be a legal holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued as a global security, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations For Global Securities

As an indirect holder, an investor’s rights relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued in definitive certificated form under the limited circumstances described below, we will have the option of making payments by check mailed to the addressesonly as global securities, an investor should be aware of the persons entitledfollowing:

Special Situations When A Global Security Will Be Terminated

In a few special situations described below, a global security will terminate and interests in it will be exchanged for physical certificates representing those interests. After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor. Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own names, so that they will be direct holders. We have described the rights of holders and street name investors above.

A global security will terminate when the following special situations occur:

PLAN OF DISTRIBUTION

We may sell the securities being offered hereby in one or more of the following ways from time to time:

We will set forth in a prospectus supplement the terms of that particular offering of securities, including:

Agents

We may designate agents who agree to use their reasonable efforts to solicit purchases of our securities for the period of their appointment or to sell our securities on a continuing basis.

Underwriters

If we use underwriters for a sale of securities, the underwriters will acquire the securities for their own account. The underwriters may resell the securities in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. The obligations of the underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. The underwriters will be obligated to purchase all the securities of the series offered if they purchase any of the securities of that series. We may change from time to time pursuantany initial public offering price and any discounts or concessions the underwriters allow or reallow or pay to underwritten public offerings, negotiated transactions, block trades ordealers. We may use underwriters with whom we have a combinationmaterial relationship. We will describe the nature of these methods or throughany such relationship in any prospectus supplement naming any such underwriter. Only underwriters or dealers, through agents and/orwe name in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

Direct Sales

We may also sell securities directly to one or more purchasers. The securities may be distributed from time to time in onepurchasers without using underwriters or more transactions:

Each time that we sell securities covered by this prospectus, we will provide a prospectus supplement or supplements that will describe the method of distribution and set forth the terms and conditions of the offering of such securities, including the offering price of the securities and the proceeds to us, if applicable.

Offers to purchase the securities being offered by this prospectus may be solicited directly. Agents may also be designated to solicit offers to purchase the securities from time to time. Any agent involved in the offer or sale of our securities will be identified in a prospectus supplement.

If a dealer is utilized in the sale of the securities being offered by this prospectus, the securities will be sold to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale.

If an underwriter is utilized in the sale of the securities being offered by this prospectus, an underwriting agreement will be executed with the underwriter at the time of sale and the name of any underwriter will be provided in the prospectus supplement that the underwriter will use to make resales of the securities to the public. In connection with the sale of the securities, we or the purchasers of securities for whom the underwriter may act as agent, may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter 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 and/or commissions from the purchasers for which they may act as agent. Unless otherwise indicated in a prospectus supplement, an agent will be acting on a best efforts basis and a dealer will purchase securities as a principal, and may then resell the securities at varying prices to be determined by the dealer.

Any compensation paid to underwriters, dealers or agents in connection with the offering of the securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers will be provided in the applicable prospectus supplement.agents. Underwriters, dealers and agents participatingthat participate in the distribution of the securities may be deemed to be underwriters within the meaning ofas

defined in the Securities Act, and any discounts andor commissions received by themthey receive from us and any profit realized by them on their resale of the securities may be deemed to betreated as underwriting discounts and commissions.commissions under the Securities Act. We will identify in the applicable prospectus supplement any underwriters, dealers or agents and will describe their compensation. We may enter intohave agreements to indemnifywith the underwriters, dealers and agents to indemnify them against specified civil liabilities, including liabilities under the Securities Act, or to contribute to payments they may be required to make in respect thereof and to reimburse those persons for certain expenses.

Any common stock or preferred stock will be listed on The Nasdaq Global Market, but any other securities may or may not be listed on a national securities exchange. To facilitate the offering of securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. This may include over-allotments or short sales of the securities, which involve the sale by persons participating in the offering of more securities than were sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option, if any. In addition, these 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 dealers participating in the 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. These transactions may be discontinued at any time.

We may engage in at the market offerings into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act. In addition, we may enter into derivative transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement so indicates, in connection with those derivatives, the third parties may sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use securities pledged by us or 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 such sale transactions will be an underwriter and, if not identified in this prospectus, will be named in the applicable prospectus supplement (or a post-effective amendment). In addition, we may otherwise loan or pledge securities to a financial institution or other third party that in turn may sell the securities short using this prospectus and an applicable prospectus supplement. Such financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

The specific terms of any lock-up provisions in respect of any given offering will be described in the applicable prospectus supplement.

In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc., or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate proceeds of the offering.

The underwriters,Underwriters, dealers and agents may engage in transactions with us, or perform services for us in the ordinary course of their businesses.

At-the-Market Offerings

To the extent that we make sales through one or more underwriters or agents in at-the-market offerings, we will do so pursuant to the terms of a sales agency financing agreement or other at-the-market offering arrangement between us, on one hand, and the underwriters or agents, on the other. If we engage in at-the-market sales pursuant to any such agreement, we will issue and sell our securities through one or more underwriters or agents, which may act on an agency basis or a principal basis. During the term of any such agreement, we may sell securities on a daily basis in exchange transactions or otherwise as we agree with the underwriters or agents. Any such agreement will provide that any securities sold will be sold at prices related to the then prevailing market prices for our securities. Therefore, exact figures regarding proceeds that will be raised or commissions to be paid cannot be determined as of the date of this prospectus. As it often customary to these offerings, we may agree to sell, and the relevant underwriters or agents may agree to solicit offers to purchase, blocks of our common stock or other securities. The terms of any such agreement will be set forth in more detail in the applicable prospectus or prospectus supplement. For example, on July 20, 2020, we entered into a purchase agreement with Lincoln Park Capital Fund, LLC, which provides that, upon the terms and subject to the conditions and limitations set forth therein, we may sell to Lincoln Park up to $10,000,000 of our common stock, of which we have sold $1,000,000 of shares of our common stock as of August 17, 2020.

Trading Markets and Listing of Securities

Unless otherwise specified in the applicable prospectus supplement, each class or series of securities will be a new issue with no established trading market, other than our common stock, which are listed on The Nasdaq Capital Market. We may elect to list any other class or series of securities on any exchange or market, but we are not obligated to do so. It is possible that one or more underwriters may make a market in a class or series of securities, but the underwriters will not be obligated to do so and may discontinue any market making at any time without notice. We cannot give any assurance as to the liquidity of the trading market for any of the securities.

Stabilization Activities

Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids in accordance with Regulation M under the Securities Exchange Act of 1934, as amended, or the Exchange Act. Overallotment involves sales in excess of the offering size, which create a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would otherwise be. If commenced, the underwriters may discontinue any of these activities at any time.

Passive Market Making

Any underwriters who are qualified market makers on The Nasdaq Capital Market may engage in passive market making transactions in the securities on The Nasdaq Capital Market in accordance with Rule 103

of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for which they receive compensation.such security. If all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.

LEGAL MATTERS

Latham & WatkinsDLA Piper LLP (US), San Diego, California will pass for us upon certain legal matters relating to the issuance and salevalidity of the securities being offered hereby on behalf of Conatus Pharmaceuticals Inc. Additionalby this prospectus and applicable prospectus supplement, and counsel named in the applicable prospectus supplement will pass upon legal matters may be passed upon for us or any underwriters, dealers or agents, by counsel that we will name in the applicable prospectus supplement.agents.

EXPERTS

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2016,2019, as set forth in their report, which is incorporated by reference in this prospectus and elsewhere in the registration statement. Our financial statements are incorporated by reference in reliance on Ernst & Young LLP’s report, given on their authority as experts in accounting and auditing.

The consolidated financial statements of Histogen Inc. as of and for the years ended December 31, 2019 and 2018 included in the Form S-4/A filed with the SEC on March 30, 2020, have been audited by Mayer Hoffman McCann P.C., independent registered public accounting firm, as set forth in their report (which report includes an explanatory paragraph regarding the existence of substantial doubt about the Company’s ability to continue as a going concern) have been incorporated by reference in this prospectus in reliance on the report of Mayer Hoffman McCann P.C., given on the authority of such firm as experts in auditing and accounting in giving said reports.

WHERE YOU CAN FIND ADDITIONAL INFORMATION

We are a reporting company and file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov. Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and Current Reports on Form 8-K, including any amendments to those reports, and other information that we file with or furnish to the SEC pursuant to Section 13(a) or 15(d) of the Exchange Act can also be accessed free of charge through the investor relations page of our website located at http://investors.histogen.com. These filings will be available as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. Information contained on our website is not part of this prospectus.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to “incorporate by reference” information that we file with it into this prospectus, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus. Information in this prospectus supersedes information incorporated by reference that we filed with the SEC prior to the date of this prospectus, while information that we file later with the SEC will automatically update and supersede the information in this prospectus. We incorporate by reference into this registration statement and prospectus the following documents, and any future filings we will make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of the initial registration statement but prior to effectiveness of the registration statement and after the date of this prospectus but prior to the termination of the offering of the securities covered by this prospectus (other than current reports or portions thereof furnished under Item 2.02 or Item 7.01 of Form 8-K):

We will provide 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 into this prospectus but not delivered with this prospectus upon written or oral request at no cost to the requester. Requests should be directed to:

Histogen Inc.

10655 Sorrento Valley Road, Suite 200

San Diego, CA 92121

(858) 526-3100

Attention: Investor Relations

$100,000,000125,000,000

Common Stock

Preferred Stock

Debt Securities

Warrants

Units

Common Stock

Prospectus

PROSPECTUS                , 2020

August     , 2017

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Other Expenses of Issuance and Distribution

The following table sets forth the various expenses payable by the registrantto be incurred in connection with the registration of the securities being registered hereby. All amounts are estimates excepthereby, all of which will be borne by the SEC registration fee and the FINRA filing fee.registrant.

Indemnification of Officers and Directors

Section 102145 of the General Corporation LawDGCL authorizes a court to award or a corporation’s board of directors to grant indemnification to directors and officers in terms sufficiently broad to permit such indemnification under certain circumstances for liabilities (including reimbursement for expenses incurred) arising under the StateSecurities Act.

Our certificate of Delaware permitsincorporation includes a corporationprovision that, to eliminatethe fullest extent permitted by the DGCL, eliminates the personal liability of our directors of a corporation to the corporation or its stockholders for monetary damages for a breach of fiduciary duty as a director, except where the director breached his duty of loyalty, failed to act in good faith, engaged in intentional misconduct or knowingly violated a law, authorized the payment of a dividend or approved a stock repurchase in violation of Delaware corporate law or obtained an improper personal benefit. Our amended and restateddirector. In addition, together our certificate of incorporation provides that no directorand our bylaws require us to indemnify, to the fullest extent permitted by law, any person made or threatened to be made a party to an action, suit or proceeding (whether criminal, civil, administrative or investigative) by reason of the Registrant shall be personally liablefact that such person is or was, or has agreed to itbecome,

a director or its stockholders for monetary damages forofficer of Histogen or any breachpredecessor of fiduciary dutyours, or serves or served at any other enterprise as a director, notwithstanding any provision of law imposing such liability, except to the extent that the General Corporation Law of the State of Delaware prohibits the eliminationofficer or limitation of liability of directors for breaches of fiduciary duty.

Section 145 of the General Corporation Law of the State of Delaware provides that a corporation has the power to indemnify a director, officer, employee at our request or agent of the corporation, or a person serving at the request of the corporation for another corporation, partnership, joint venture, trust or other enterprise in related capacitiesany predecessor of ours, against expenses (including attorneys’ fees), liabilities, losses, judgments, fines, and amounts paid in settlement actually and reasonably incurred by the person in connection with an action, suit orany proceeding, to which he was or is a party or is threatened to be made a party to any threatened, ending or completed action, suit or proceeding by reason of such position, if such person acted in good faith and in a manner which he or she reasonably believed to be in, or not opposed to, the best interests of the corporation,Corporation, and, inwith respect to any criminal action or proceeding, had no reasonable cause to believe his conduct was unlawful, except that, in the case of actions brought by or in the right of the corporation, no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation unless and only to the extent that the Court of Chancery or other adjudicating court determines that, despite the adjudication of liability but in view of all of the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the Court of Chancery or such other court shall deem proper.

Our amended and restated bylaws provide that we will indemnify each person who was or is a party or threatened to be made a party to any threatened, pending or completed action, suit or proceeding (other than an action by or in the right of us) by reason of the fact that he or she is or was, or has agreed to become, a director or officer, or is or was serving, or has agreed to serve, at our request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise (all such persons being referred to as an “Indemnitee”), or by reason of any action alleged to have been taken or

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omitted in such capacity, against all expenses (including attorneys’ fees), judgments, fines and amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding and any appeal therefrom, if such Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, or not opposed to, our best interests, and, with respect to any criminal action or proceeding, he or she had no reasonable cause to believe his or her conduct was unlawful. Our amendedWe are required to advance expenses incurred by our directors, officers, employees and restated bylaws also provide that we will indemnifyagents in defending any Indemnitee who was or is a party to an action or suitproceeding for which indemnification is required or permitted, subject to certain limited exceptions. The indemnification rights conferred by or in the rightour certificate of us to procure a judgment in our favor by reason of the fact that the Indemnitee is or was, or has agreed to become, a director or officer, or is or was serving, or has agreed to serve, at our request as a director, officer, partner, employee or trustee of, or in a similar capacity with, another corporation, partnership, joint venture, trust or other enterprise, or by reason of any action alleged to have been taken or omitted in such capacity, against all expenses (including attorneys’ fees)incorporation and to the extent permitted by law, amounts paid in settlement actually and reasonably incurred in connection with such action, suit or proceeding, and any appeal therefrom, if the Indemnitee acted in good faith and in a manner he or she reasonably believed to be in, orbylaws are not opposed to, our best interests, except that no indemnification shall be made with respect to any claim, issue or matter as to which such person shall have been adjudged to be liable to us, unless a court determines that, despite such adjudication but in view of all of the circumstances, he or she is entitled to indemnification of such expenses. Notwithstanding the foregoing, to the extent that any Indemnitee has been successful, on the merits or otherwise, he or she will be indemnified by us against all expenses (including attorneys’ fees) actually and reasonably incurred in connection therewith. Expenses must be advanced to an Indemnitee under certain circumstances.exclusive.

WeIn addition, we have entered into indemnification agreements with each of our executive officers and directors. We also maintain an officers and directors and officers. These indemnification agreementsliability insurance policy.

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The foregoing may require us, among other things, to indemnifyreduce the likelihood of derivative litigation against our directors and executive officers and may discourage or deter stockholders or management from suing directors or executive officers for some expenses, including attorneys’ fees, judgments, finesbreaches of their duty of care, even though such actions, if successful, might otherwise benefit the company and settlement amounts incurredour stockholders.

The underwriting agreement that we may enter into, Exhibit 1.1 to this registration statement, will provide for indemnification by a director or officer in any action or proceeding arising outunderwriters of his or her service as one ofthe company, our directors, orour officers orwho sign the registration statement and our controlling persons, if any, of our subsidiaries or any other company or enterprise to whichfor some liabilities, including liabilities arising under the person provides services at our request.Securities Act.

We maintain a general liability insurance policy that covers certain liabilities of directors and officers of our corporation arising out of claims based on acts or omissions in their capacities as directors or officers.Exhibits

(a)Exhibits

A list of exhibits filed with this registration statement on Form S-3 is set forth on the Exhibit Index and is incorporated herein by reference.II-2

(a) Undertakings

The undersigned registrant hereby undertakes:

(1)1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

(i) Toto include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

Act; (ii) Toto reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Securities and Exchange Commission (the “Commission”), pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20 percent change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

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(iii) Toto include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

provided,Provided, however, that paragraphs (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) above do not apply if the registration statement is on Form S-3 or Form F-3 and the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the Securities and Exchange Commission by the registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange Act of 1934 (the “Exchange Act”), that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

(2)2) That, for the purpose of determining any liability under the Securities Act, of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3)

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3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(5)4) That, for the purpose of determining liability under the Securities Act of 1933 to any purchaser:

(A)i. Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

(B)ii. Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5) or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by Section 10(a) of the Securities Act of 1933 shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which thatthe prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.Provided,,however, that no statement made in a registration statement or prospectus that is part of the registration statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date.

(6)5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities:

Thesecurities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

(i)i. Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

(ii)ii. Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

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(iii)iii. The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of thean undersigned registrant; and

(iv)iv. Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(b) The undersigned registrant hereby undertakes that,6) That, for purposes of determining any liability under the Securities Act, of 1933, each filing of the registrant’s annual report pursuant to Sectionsection 13(a) or Sectionsection 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Sectionsection 15(d) of the Securities Exchange Act of 1934)Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initialbona fide offering thereof.

(h)

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7) To file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under Section 305(b)(2) of the Trust Indenture Act.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

(j) The undersigned registrant hereby undertakes to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of Section 310 of the Trust Indenture Act (the “Act”) in accordance with the rules and regulations prescribed by the SEC under Section 305(b)(2) of the Act.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned thereunto duly authorized in the City of San Diego, State of California, on the 17th day of August 2017.17, 2020.

POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS,, that each person whose signature appears below constitutes and appoints jointlyRichard W. Pascoe and severally, Steven J. Mento, Ph.D. and Michelle L. Vandertie,Susan A. Knudson, and each one of them acting individually, as his or her true and lawful attorneys-in-fact and agents, eachagent, with full power of each to act alone, with full powers of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement (including post-effective amendments and to sign any related registration statement for the same offering covered by this registration statement that is to be effective upon filingstatements filed pursuant to Rule 462(b) promulgated under the Securities Act of 1933, as amended,462 and all post-effective amendments thereto,otherwise), and to file the same with all exhibits thereto, and allother documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises,connection therewith, as fully tofor all intents and purposes as he might or could do in person, hereby ratifying and confirming that each ofall said attorneys-in-fact and agents, or any of them or his or their substitute or substitutes,resubstitute, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the dates indicated.

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EXHIBIT INDEX

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