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Filed Pursuant to Rule 424(b)(5)
Registration No. 333-224880
PROSPECTUS SUPPLEMENT
(To Prospectus dated May 23, 2018)
FORTE BIOSCIENCES, INC.
$30,000,000 Common Stock

We have entered into an At Market Issuance Sales Agreement, or the sales agreement, with Ladenburg Thalmann & Co. Inc., or Ladenburg, relating to shares of our common stock, $0.001 par value per share, offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the sales agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $30,000,000 from time to time through Ladenburg acting as sales agent.
Our common stock is listed on the Nasdaq Capital Market under the symbol “FBRX.” The last reported sale price of our common stock on September 3, 2020 was $27.54 per share.
Upon our delivery of a placement notice and subject to the terms and conditions of the sales agreement, Ladenburg may sell shares of our common stock by methods deemed to be an “at the market offering” as defined in Rule 415 promulgated under the Securities Act of 1933, as amended, or the Securities Act. Ladenburg is not required to sell any specific number or dollar amounts of securities but will act as sales agent using its commercially reasonable efforts on our behalf, consistent with its normal trading and sales practices, on mutually agreed terms between Ladenburg and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.
Ladenburg will be entitled to compensation at a fixed commission rate of 3.0% of the gross proceeds of each sale of shares of our common stock. See “Plan of Distribution” on page S-14 for a description of compensation payable to Ladenburg. In connection with the sale of our shares of common stock on our behalf, Ladenburg may be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation of Ladenburg may be deemed to be underwriting commissions or discounts. We have also agreed to provide indemnification and contribution to Ladenburg with respect to certain liabilities, including liabilities under the Securities Act.
We are an emerging growth company as that term is used in the Jumpstart Our Business Startups Act of 2012 and, as such, have elected to comply with certain reduced public company reporting requirements.

Investing in our common stock involves a high degree of risk. Before making an investment decision, please read the information under the heading “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents incorporated by reference into this prospectus supplement and the accompanying base prospectus.
Neither the Securities and Exchange Commission, or SEC, nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

Ladenburg Thalmann & Co. Inc.
The date of this prospectus is September 4, 2020

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TABLE OF CONTENTS
Prospectus Supplement

 	  	Page	 	
ABOUT THIS PROSPECTUS SUPPLEMENT	  	 	S-1	 	
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	  	 	S-2	 	
PROSPECTUS SUPPLEMENT SUMMARY	  	 	S-3	 	
THE OFFERING	  	 	S-5	 	
RISK FACTORS	  	 	S-6	 	
USE OF PROCEEDS	  	 	S-8	 	
DILUTION	  	 	S-9	 	
PLAN OF DISTRIBUTION	  	 	S-14	 	
LEGAL MATTERS	  	 	S-15	 	
EXPERTS	  	 	S-15	 	
WHERE YOU CAN FIND ADDITIONAL INFORMATION	  	 	S-15	 	
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	  	 	S-16	 	

ABOUT THIS PROSPECTUS	  	 	i	 	
SUMMARY	  	 	1	 	
RISK FACTORS	  	 	6	 	
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	  	 	7	 	
RATIO OF EARNINGS TO FIXED CHARGES	  	 	8	 	
USE OF PROCEEDS	  	 	8	 	
DESCRIPTION OF CAPITAL STOCK	  	 	8	 	
DESCRIPTION OF DEBT SECURITIES	  	 	12	 	
DESCRIPTION OF WARRANTS	  	 	19	 	
LEGAL OWNERSHIP OF SECURITIES	  	 	21	 	
PLAN OF DISTRIBUTION	  	 	24	 	
LEGAL MATTERS	  	 	26	 	
EXPERTS	  	 	26	 	
WHERE YOU CAN FIND MORE INFORMATION	  	 	26	 	
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	  	 	27	 	
DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITY	  	 	28	 	
 
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ABOUT THIS PROSPECTUS SUPPLEMENT
This document is in two parts. The first part is the prospectus supplement, including the documents incorporated by reference, which describes the specific terms of this offering. The second part, the accompanying prospectus, including the documents incorporated by reference, provides more general information. Before you invest, you should carefully read this prospectus supplement, the accompanying prospectus, all information incorporated by reference herein and therein, as well as the additional information described under “Where You Can Find Additional Information” on page S-15 of this prospectus supplement. These documents contain information you should consider when making your investment decision. This prospectus supplement may add, update or change information contained in the accompanying prospectus. To the extent there is a conflict between the information contained in this prospectus supplement, on the one hand, and the information contained in the accompanying prospectus or any document incorporated by reference therein filed prior to the date of this prospectus supplement, on the other hand, you should rely on the information in this prospectus supplement. If any statement in one of these documents is inconsistent with a statement in another document having a later date — for example, a document filed after the date of this prospectus supplement and incorporated by reference in this prospectus supplement and the accompanying prospectus — the statement in the document having the later date modifies or supersedes the earlier statement.
This prospectus supplement is part of a registration statement that we filed with the Securities and Exchange Commission using a “shelf” registration process. Under the shelf registration process, we may from time to time offer and sell any combination of the securities described in the accompanying prospectus up to a total dollar amount of $100.0 million, of which this offering is a part.
You should rely only on the information contained or incorporated by reference in this prospectus supplement, the accompanying prospectus and in any free writing prospectuses we may provide to you in connection with this offering. We have not, and Ladenburg has not, authorized any other person to provide you with any information that is different. If anyone provides you with different or inconsistent information, you should not rely on it. We and Ladenburg take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. Additionally, you should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference herein and therein, and in any free writing prospectus that we may authorize for use in connection with this offering, is accurate only as of the date of those respective documents. Our business, financial condition, results of operations and prospects may have changed since those dates. We are offering to sell, and seeking offers to buy, shares of our common stock only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the offering of the common stock in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement must inform themselves about, and observe any restrictions relating to, the offering of the common stock and the distribution of this prospectus supplement outside the United States. This prospectus supplement does not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.
We further note that the representations, warranties and covenants made by us in any agreement that is filed as an exhibit to any document that is incorporated by reference in the accompanying prospectus were made solely for the benefit of the parties to such agreement, including, in some cases, for the purpose of allocating risk among the parties to such agreements, and should not be deemed to be a representation, warranty or covenant to you. Moreover, such representations, warranties or covenants were accurate only as of the date when made. Accordingly, such representations, warranties and covenants should not be relied on as accurately representing the current state of our affairs.
This prospectus supplement, the accompanying prospectus and the information incorporated herein and therein by reference include trademarks, servicemarks and tradenames owned by us or other companies. All
 
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trademarks, servicemarks and tradenames included or incorporated by reference in this prospectus supplement or the accompanying prospectus are the property of their respective owners.
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS
This prospectus supplement and our SEC filings that are incorporated by reference into this prospectus supplement contain or incorporate by reference forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act. These forward-looking statements are based on current expectations and beliefs and involve numerous risks and uncertainties that could cause actual results to differ materially from expectations. These forward-looking statements should not be relied upon as predictions of future events as it cannot be assured that the events or circumstances reflected in these statements will be achieved or will occur. You can identify forward-looking statements by the use of forward-looking terminology including “anticipates,” “believes,” “could,” “seeks,” “estimates,” “expects,” “intends,” “may,” “plans,” “potential,” “predicts,” “projects,” “pro forma,” “should,” “will,” “would,” or the negative of these words and phrases or other variations of these words and phrases or comparable terminology. All statements other than statements of historical fact are statements that could be deemed forward-looking statements. For example, forward-looking statements include, but are not limited to statements about:
 
 	•	 	the expected benefits of, and potential value created by, the merger between Tocagen and Forte Subsidiary (as defined below);	
 
 	•	 	any statements of the plans, strategies and objectives of management for future operations;	
 
 	•	 	any statements concerning proposed new products, services or developments;	
 
 	•	 	any statements regarding any business disruption or potential impact to our business due to COVID-19;	
 
 	•	 	any statements regarding future economic conditions or performance;	
 
 	•	 	our ability to protect our intellectual property and operate our business without infringing upon the intellectual property rights of others;	
 
 	•	 	our estimates regarding the sufficiency of our cash resources and our need for additional funding; and	
 
 	•	 	our intended use of the net proceeds from offerings of our securities under this prospectus supplement.	
Forward-looking statements reflect our current views with respect to future events, are based on assumptions and are subject to risks and uncertainties. We cannot guarantee that we actually will achieve the plans, intentions or expectations expressed in our forward-looking statements and you should not place undue reliance on these statements. There are a number of important factors that could cause our actual results to differ materially from those indicated or implied by forward-looking statements. These important factors include those discussed under the heading “Risk Factors” contained or incorporated in this prospectus supplement and the accompanying prospectus and any free writing prospectus we may authorize for use in connection with a specific offering. These factors and the other cautionary statements made in this prospectus supplement and the accompanying prospectus should be read as being applicable to all related forward-looking statements whenever they appear in this prospectus supplement and the accompanying prospectus. Except as required by law, we do not assume any obligation to update any forward-looking statement. We disclaim any intention or obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.
 
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PROSPECTUS SUPPLEMENT SUMMARY
This summary highlights selected information about us, this offering and information appearing elsewhere in this prospectus supplement and in the documents we incorporate by reference. This summary is not complete and does not contain all the information you should consider before investing in our common stock pursuant to this prospectus supplement and the accompanying prospectus. Before making an investment decision, to fully understand this offering and its consequences to you, you should carefully read this entire prospectus supplement and the accompanying prospectus, including “Risk Factors” beginning on page S-6 of this prospectus supplement and the financial statements and related notes and the other information that we incorporated by reference herein, including our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and any other filings that we file with the SEC from time to time.
Unless the context otherwise requires, all references in this prospectus to “Forte,” “we,” “us,” “our,” “the Company” or similar words refer to Forte Biosciences, Inc., together with our consolidated subsidiary, Forte Subsidiary, Inc.
Overview
We are a clinical-stage biopharmaceutical company focused on advancing through clinical trials our lead product candidate, FB-401, which is a live biotherapeutic for the treatment of inflammatory skin disease, including pediatric and adult patients with atopic dermatitis. There is currently a significant unmet need for safe and effective therapies for pediatric atopic dermatitis patients. FB401 was developed in collaboration with the National Institutes of Health (“NIH”), and the National Institute of Allergy and Infectious Diseases (“NIAID”).
We are developing a new approach to treating inflammatory skin disease using a topical live biotherapeutic, FB-401, which consists of three therapeutic strains of a commensal gram-negative bacteria, Roseomonas mucosa, that were specifically selected for their impact on key parameters of inflammatory skin disease. Genetic-based microbiome identification revealed significant differences in the Gram-negative skin biome between atopic dermatitis (“AD”) patients and healthy volunteers (“HV”). Over 50% of AD patients did not have any culturable Gram-negative flora. Our extensive preclinical and mechanism of action data demonstrate that FB-401 improves atopic dermatitis disease parameters by driving tissue repair and anti-inflammation as well as suppressing potentially harmful bacteria like S. aureus. Specifically, we believe that FB-401:
 
 	•	 	drives immune pathways that are defective;	
 
 	•	 	suppresses Staphylococcus aureus growth; and	
 
 	•	 	improves skin barrier function.	
To date, a Phase 1/2a study has been completed with pediatric and adult patients, demonstrating significant reduction in atopic dermatitis disease and pruritus, as well as control of S. aureus while tapering/eliminating steroid use. We are currently planning to initiate a double-blinded randomized Phase 2 clinical trial for mild to moderate AD in the third quarter of 2020.
Recent Developments; Corporate Information
Forte entered into a business combination (“Merger”) between Forte Subsidiary, Inc. (“Forte Subsidiary”) and Tocagen, Inc. (“Tocagen”), a publicly traded biotechnology company. The merger closed on June 15, 2020, in which Telluride Merger Sub, Inc. a wholly-owned subsidiary of Tocagen, merged with and into Forte Subsidiary, with Forte Subsidiary surviving that Merger as a wholly-owned subsidiary of Tocagen. Immediately prior to the closing of the Merger, the then outstanding shares of Tocagen common stock were adjusted with a

 
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reverse stock split of 15 to 1. At the closing of the Merger, each share of Forte Subsidiary’s common stock was converted into the right to receive approximately 3.1624 shares of Tocagen common stock (before giving effect of the reverse split). Immediately prior to closing of the Merger, Tocagen changed its name to Forte Biosciences, Inc. Our common stock is publicly traded on the Nasdaq Capital Market under the ticker symbol FRBX. Prior to the Merger, Forte Subsidiary was a privately held company incorporated in Delaware on May 3, 2017.
Our principal executive offices are located at 1124 W Carson Street MRL Building 3-320, Torrance, California 90502, and our telephone number at that address is (310) 618-6994. Our corporate website is located at www.fortebiorx.com. The information contained on, or that can be accessed through, our website is not a part of this prospectus supplement. Investors should not rely on any such information in deciding whether to purchase our common stock. We have included our website address in this prospectus supplement solely as an inactive textual reference.
We make available free of charge through our website our annual report on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Securities Exchange Commission, or SEC. The information contained in, or that can be accessed through, our website is not part of this prospectus supplement.
Implications of Being an Emerging Growth Company
We qualify as an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. As an emerging growth company, we intend to take advantage of specified reduced disclosure and other requirements that are otherwise applicable generally to public companies. These provisions include:
 
 	•	 	allowance to provide only two years of audited financial statements in addition to any required unaudited interim financial statements with correspondingly reduced “ Management ’ s Discussion and Analysis of Financial Condition and Results of Operations ” disclosure;	
 
 	•	 	reduced disclosure about our executive compensation arrangements;	
 
 	•	 	exemption from the requirements of holding non-binding advisory votes on executive compensation or golden parachute arrangements; and	
 
 	•	 	exemption from the auditor attestation requirement in the assessment of our internal control over financial reporting.	
We may take advantage of these provisions for up to five years or such earlier time that we are no longer an emerging growth company. We would cease to be an emerging growth company on the date that is the earliest of: (i) the last day of the fiscal year in which we have total annual gross revenues of $1.07 billion or more; (ii) the last day of our fiscal year following the fifth anniversary of the date of the completion of our initial public offering; (iii) the date on which we have issued more than $1.07 billion in nonconvertible debt during the previous three years; or (iv) the date on which we are deemed to be a large accelerated filer under the rules of the SEC. Under the JOBS Act, emerging growth companies can also delay adopting new or revised accounting standards until such time as those standards apply to private companies. We have elected not to avail our self of this exemption from new or revised accounting standards and, therefore, will be subject to the same new or revised accounting standards as other public companies that are not emerging growth companies.

 
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THE OFFERING

Issuer	  	Forte Biosciences, Inc.	
		
Common stock offered by us	  	Shares having an aggregate offering price of up to $30,000,000.	
		
Common stock to be outstanding after this offering	  	Up to 12,305,054 shares of common stock, assuming sales of 1,089,324 shares of common stock in this offering at an assumed offering price of $27.54 per share, which was the last reported sale price of our common stock on The Nasdaq Capital Market on September 3, 2020. The actual number of shares issued will vary depending on the sales prices at which our common stock is sold under this offering.	
		
Manner of offering	  	“At the market offering” that may be made from time to time through our sales agent, Ladenburg Thalmann & Co. Inc. See “Plan of Distribution” on page S-14.	
		
Use of proceeds	  	We intend to use the net proceeds for working capital and general corporate purposes, 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. Please see “Use of Proceeds” on page S-8.	
		
Risk factors	  	This investment involves a high degree of risk. See “Risk Factors” beginning on page S-6 of this prospectus supplement, as well as the other information included in or incorporated by reference in this prospectus supplement and the accompanying prospectus, for a discussion of risks you should carefully consider before investing in our securities.	
		
Nasdaq Capital Market symbol	  	FBRX	
The number of shares of our common stock that will be outstanding after this offering is based on 11,198,315 shares of common stock outstanding as of June 30, 2020, after giving effect to the reverse stock split of 15 to 1 that was effective on June 15, 2020, and excludes the following shares, which have also been updated for the reverse stock split:
 
 	•	 	2,752,546 shares of our common stock issuable upon exercise of warrants outstanding as of June 30, 2020, with an exercise price of $10.56 per share and 4,434 shares of our common stock issuable upon exercise of warrants outstanding as of June 30, 2020 with an exercise price of $140.25 per share;	
 
 	•	 	821,910 shares of our common stock issuable upon exercise of options outstanding as of June 30, 2020, with a weighted-average exercise price of $6.21 per share; and	
 
 	•	 	500,000 shares of our common stock available for future grants under our 2020 Inducement Equity Incentive Plan adopted as of July 26, 2020.	
 
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RISK FACTORS
Investing in our securities involves a high degree of risk and uncertainty. In addition to the other information included or incorporated by reference in this prospectus supplement and the accompanying prospectus, you should carefully consider the risks described below, before making an investment decision with respect to the securities. We expect to update these Risk Factors from time to time in the periodic and current reports that we file with the SEC after the date of this prospectus supplement. These updated Risk Factors will be incorporated by reference in this prospectus supplement and the accompanying prospectus. Please refer to these subsequent reports for additional information relating to the risks associated with investing in our common stock. If any of such risks and uncertainties actually occurs, our business, financial condition, and results of operations could be severely harmed. This could cause the trading price of our common stock to decline, and you could lose all or part of your investment. Our actual results could differ materially from those anticipated in the forward-looking statements made throughout this prospectus supplement or the documents incorporated by reference into this prospectus supplement and the accompanying prospectus as a result of different factors, including the risks we face described below.
Risks Related to this Offering
Resales of our common stock in the public market by our stockholders during this offering may cause the market price of our common stock to fall.
We may issue common stock from time to time in connection with this offering. The issuance from time to time of these new shares of our common stock, or our ability to issue new shares of common stock in this offering, could result in resales of our common stock by our current stockholders concerned about the potential ownership dilution of their holdings. In turn, these resales could have the effect of depressing the market price for our common stock.
It is not possible to predict the aggregate proceeds resulting from sales made under the sales agreement.
Subject to certain limitations in the sales agreement and compliance with applicable law, we have the discretion to deliver a placement notice to Ladenburg at any time throughout the term of the sales agreement. The number of shares that are sold through Ladenburg after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common stock during the sales period, any limits we may set with Ladenburg in any applicable placement notice and the demand for our common stock. Because the price per share of each share sold pursuant to the sales agreement will fluctuate over time, it is not currently possible to predict the aggregate proceeds to be raised in connection with sales under the sales agreement.
The common stock offered hereby will be sold in “at the market offerings” and investors who buy shares at different times will likely pay different prices.
Investors who purchase shares in this offering at different times will likely pay different prices, and accordingly may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices and number of shares sold in this offering. In addition, subject to the final determination by our board of directors or any restrictions we may place in any applicable placement notice, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.
There may be future sales or other dilution of our equity, which may adversely affect the market price of our common stock.
We are generally not restricted from issuing additional common stock, including any securities that are convertible into or exchangeable for, or that represent the right to receive, common stock. The market price of
 
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our common stock could decline as a result of sales of common stock or securities that are convertible into or exchangeable for, or that represent the right to receive, common stock after this offering or the perception that such sales could occur.
Our management will have broad discretion over the use of the net proceeds from this offering, you may not agree with how we use the proceeds and the proceeds may not be invested successfully.
We have not designated any portion of the net proceeds from this offering to be used for any particular purpose. Accordingly, our management will have broad discretion as to the use of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of commencement of this offering. Accordingly, you will be relying on the judgment of our management with regard to the use of these net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. It is possible that, pending their use, we may invest the net proceeds in a way that does not yield a favorable, or any, return for our company. Our failure to apply these funds effectively could have a material adverse effect on our business, delay the development of our product candidates and cause the price of our common stock to decline.
You may experience immediate and substantial dilution in the book value per share of the common stock you purchase.
Because the prices per share at which shares of our common stock are sold in this offering may be substantially higher than the book value per share of our common stock, you may suffer immediate and substantial dilution in the net tangible book value of the common stock you purchase in this offering. The shares sold in this offering, if any, will be sold from time to time at various prices. After giving effect to the sale of our common stock in the maximum aggregate offering amount of $30,000,000 at an assumed offering price of $27.54 per share, the last reported sale price of our common stock on the Nasdaq Capital Market on September 3, 2020 and after deducting estimated offering commissions and expenses payable by us, our net tangible book value as of June 30, 2020 would have been approximately $53.82 million, or $4.38 per share of common stock. This represents an immediate increase in the net tangible book value of $2.16 per share to our existing stockholders and an immediate and substantial dilution in as-adjusted net tangible book value of $23.16 per share to new investors who purchase our common stock in the offering. See “Dilution” for a more detailed discussion of the dilution you may incur in connection with this offering.
 
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USE OF PROCEEDS
We will have broad discretion in the use of the net proceeds from any sale of securities offered under this prospectus supplement. We intend to use the net proceeds for working capital and general corporate purposes, 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.
Our expected use of the net proceeds to us from this offering represents our current intentions based upon our present plans and business condition. The amounts and timing of our actual expenditures will depend on numerous factors, including the progress of our research and development efforts, the status of and results from our current or future clinical trials, the timing of regulatory submissions and any unforeseen cash needs. Accordingly, our management will have broad discretion in the application of any net proceeds from this offering.
We have not determined the amount of net proceeds to be used specifically for such purposes. Pending the use of any net proceeds, we expect to invest the net proceeds in interest-bearing, marketable securities.
 
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DILUTION
If you invest in our common stock, your interest will be diluted immediately to the extent of the difference between the public offering price per share and the adjusted net tangible book value per share of our common stock after this offering.
The net tangible book value of our common stock as of June 30, 2020, was approximately $24.9 million, or approximately $2.22 per share, after giving effect to the reverse stock split of 15 to 1 that was effective on June 15, 2020. Net tangible book value per share represents the amount of our total tangible assets, excluding goodwill and intangible assets, less total liabilities, divided by the total number of shares of our common stock outstanding. Dilution per share to new investors represents the difference between the amount per share paid by purchasers for each share of common stock in this offering and the net tangible book value per share of our common stock immediately following the completion of this offering.
After giving effect to the sale of shares of our common stock in the aggregate amount of $30,000,000 at an assumed offering price of $27.54 per share, the last reported sale price of our common stock on September 3, 2020 on the Nasdaq Capital Market, and after deducting estimated commissions and estimated offering expenses, our as-adjusted net tangible book value as of June 30, 2020 would have been approximately $53.82 million or approximately $4.38 per share. This represents an immediate increase in net tangible book value of approximately $2.16 per share to our existing stockholders and an immediate dilution in as-adjusted net tangible book value of approximately $23.16 per share to purchasers of our common stock in this offering, as illustrated by the following table:

Assumed offering price per share	  				  	$	27.54	 	
Net tangible book value per share as of June 30, 2020	  	$	2.22	 	  				
Increase per share attributable to this offering	  	$	2.16	 	  				
As-adjusted net tangible book value per share as of June 30, 2020, after giving effect to this offering	  				  	$	4.38	 	
	  	 	 	 	  	 	 	 	
Dilution per share to new investors participating in this offering	  				  	$	23.16	 	
	  				  	 	 	 	
The table above assumes, for illustrative purposes only, an aggregate of 1,089,324 shares of our common stock are sold at a price of $27.54 per share, for aggregate gross proceeds of $30,000,000. The shares, if any, sold in this offering will be sold from time to time at various prices. An increase of $1.00 per share in the price at which the shares are sold from the assumed offering price of $27.54 per share shown in the table above, assuming all of our common stock in the aggregate amount of $30,000,000 is sold at that price, would increase our adjusted net tangible book value per share after the offering to $4.39 per share and increase the dilution in net tangible book value per share to new investors in this offering to $24.15 per share, after deducting commissions and estimated aggregate offering expenses payable by us. A decrease of $1.00 per share in the price at which the shares are sold from the assumed offering price of $27.54 per share shown in the table above, assuming all of our common stock in the aggregate amount of $30,000,000 is sold at that price, would decrease the adjusted net tangible book value per share after the offering to $4.37 per share and decrease the dilution in net tangible book value per share to new investors in this offering to $22.17 per share, after deducting commissions and estimated aggregate offering expenses payable by us. This information is supplied for illustrative purposes only.
The table above is based on 11,198,315 shares of our common stock outstanding as of June 30, 2020, after giving effect to the reverse stock split of 15 to 1 that was effective on June 15, 2020 and excludes the following shares which have also been updated for the reverse stock split:
 
 	•	 	2,752,546 shares of our common stock issuable upon exercise of warrants outstanding as of June 30, 2020, with an exercise price of $10.56 per share and 4,434 shares of our common	
 
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 	stock issuable upon exercise of warrants outstanding as of June 30, 2020 with an exercise price of $140.25 per share;	
 
 	•	 	821,910 shares of our common stock issuable upon exercise of options outstanding as of June 30, 2020, with a weighted-average exercise price of $6.21 per share; and	
 
 	•	 	500,000 shares of our common stock available for future grants under our 2020 Inducement Equity Incentive Plan adopted as of July 26, 2020.	
To the extent that after June 30, 2020 any outstanding options or warrants were or are exercised, new equity awards were or are issued under our equity incentive plan, or we otherwise issued or issue additional shares of common stock in the future at prices per share below the price per share for any shares sold in this offering, there will be further dilution to new investors.
DESCRIPTION OF FORTE CAPITAL STOCK
As of the date of this supplemental prospectus, our amended and restated certificate of incorporation authorizes us to issue 200,000,000 shares of common stock, par value $0.001 per share, and 10,000,000 shares of preferred stock, par value $0.001 per share. All of our authorized preferred stock is undesignated.
The following is a summary of the rights of our common and preferred stockholders, of some of the provisions of our amended and restated certificate of incorporation and amended and restated bylaws and of the Delaware General Corporation Law, or the DGCL. This summary is not complete. For more detailed information, please see our amended and restated certificate of incorporation and amended and restated bylaws, as well as the relevant provisions of the DGCL.
Common Stock
Voting. Our common stock is entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders, including the election of directors, and does not have cumulative voting rights. Accordingly, the holders of a majority of the shares of our common stock entitled to vote in any election of directors can elect all of the directors standing for election.
Dividends. Subject to preferences that may be applicable to any then-outstanding preferred stock, the holders of our common stock are entitled to receive dividends, if any, as may be declared from time to time by our board of directors out of legally available funds.
Liquidation. In the event of our liquidation, dissolution or winding-up, holders of our common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities, subject to the satisfaction of any liquidation preference granted to the holders of any outstanding shares of preferred stock.
Rights and Preferences. Holders of our common stock have no preemptive, conversion or subscription rights, and there are no redemption or sinking fund provisions applicable to its common stock. The rights, preferences and privileges of the holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that we may designate and issue in the future.
Preferred Stock
Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 10,000,000 shares of preferred stock in one or more
 
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series and to fix or alter, from time to time, the designations, powers and rights of each series of preferred stock and the qualifications, limitations or restrictions of any series of preferred stock, including dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption (including sinking fund provisions), redemption price or prices, and the liquidation preference of any wholly unissued series of preferred stock, any or all of which may be greater than the rights of our common stock, and to establish the number of shares constituting any such series. To date, none of the 10,000,000 authorized shares of preferred stock have been designated by our board of directors.
Our board of directors will fix the rights, preferences, privileges, qualifications and restrictions of the preferred stock of each series in the certificate of designation relating to each such series, including:
 
 	•	 	the title and stated value;	
 
 	•	 	the liquidation preference per share;	
 
 	•	 	the dividend rate per share, dividend period, payment date or dates and method of calculation for dividends;	
 
 	•	 	whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;	
 
 	•	 	Our right, if any, to defer payment of dividends and the maximum length of any such deferral period;	
 
 	•	 	the procedures for any auction and remarketing, if any;	
 
 	•	 	the provisions for a sinking fund, if any;	
 
 	•	 	the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;	
 
 	•	 	whether the preferred stock will be convertible into our common stock or other securities of ours, including warrants, and, if applicable, the conversion price, or how it will be calculated, and under what circumstances and the mechanism by which it may be adjusted, and the conversion period;	
 
 	•	 	whether the preferred stock will be exchangeable into debt securities or other securities of ours, and, if applicable, the exchange price, or how it will be calculated, and under what circumstances it may be adjusted, and the exchange period;	
 
 	•	 	voting rights, if any;	
 
 	•	 	preemptive rights, if any;	
 
 	•	 	restrictions on transfer, sale or other assignment, if any;	
 
 	•	 	whether interests in the preferred stock will be represented by depositary shares;	
 
 	•	 	the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;	
 
 	•	 	any limitations on issuances of any class or series of preferred stock ranking senior to or on parity with the series of preferred stock being issued as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and	
 
 	•	 	any other specific terms, rights, preferences, privileges, qualifications or limitations of, or restrictions on the preferred stock.	
The laws of the state of Delaware, the state of our incorporation, provide that the holders of preferred stock will have the right to vote separately, as a class, on any proposal involving fundamental changes in the rights of holders of such preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.
 
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The issuance of preferred stock could adversely affect the voting power, conversion or other rights of holders of our common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. Preferred stock could be issued quickly with terms designed to delay, deter or prevent a change in control of Forte or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of Forte common stock.
Anti-Takeover Effects of Provisions of Forte’s Amended and Restated Certificate of Incorporation, Forte’s Amended and Restated Bylaws and Delaware Law
Delaware Anti-Takeover Law
We are subject to Section 203 of the DGCL, which generally prohibits a public Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless:
 
 	•	 	prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;	
 
 	•	 	the interested stockholder owned at least 85% of the voting stock of the corporation outstanding upon consummation of the transaction, excluding for purposes of determining the number of shares outstanding (1) shares owned by persons who are directors and also officers and (2) shares owned by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or	
 
 	•	 	on or subsequent to the consummation of the transaction, the business combination is approved by the board and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock which is not owned by the interested stockholder.	
Section 203 of the DGCL defines a business combination to include:
 
 	•	 	any merger or consolidation involving the corporation and the interested stockholder;	
 
 	•	 	any sale, transfer, pledge or other disposition involving the interested stockholder of 10% or more of the assets of the corporation;	
 
 	•	 	subject to exceptions, any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder;	
 
 	•	 	subject to exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder; and	
 
 	•	 	the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.	
In general, Section 203 of the DGCL defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by the entity or person.
Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws
Provisions of our amended and restated certificate of incorporation and amended and restated bylaws, may delay or discourage transactions involving an actual or potential change in its control or change in its management, including transactions in which stockholders might otherwise receive a premium for their shares or
 
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transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these provisions could adversely affect the price of our common stock. Among other things, our amended and restated certificate of incorporation and amended and restated bylaws:
 
 	•	 	permit our board of directors to issue up to 10,000,000 shares of preferred stock, with any rights, preferences and privileges as they may designate;	
 
 	•	 	provide that the authorized number of directors may be changed only by resolution adopted by a majority of our board of directors;	
 
 	•	 	provide that the board of directors or any individual director may only be removed with cause and the affirmative vote of the holders of at least 66 2/3% of the voting power of all of its then outstanding Forte common stock;	
 
 	•	 	provide that all vacancies, including newly created directorships, may, except as otherwise required by law or subject to the rights of holders of preferred stock as designated from time to time, be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum;	
 
 	•	 	divides our board of directors into three classes;	
 
 	•	 	require that any action to be taken by its stockholders must be effected at a duly called annual or special meeting of stockholders and not be taken by written consent or electronic transmission;	
 
 	•	 	provide that stockholders seeking to present proposals before a meeting of stockholders or to nominate candidates for election as directors at a meeting of stockholders must provide notice in writing in a timely manner and also specify requirements as to the form and content of a stockholder’s notice;	
 
 	•	 	do not provide for cumulative voting rights (therefore allowing the holders of a majority of the shares of our common stock entitled to vote in any election of directors to elect all of the directors standing for election, if they should so choose);	
 
 	•	 	provide that special meetings of its stockholders may be called only by the chairman of our board of directors, its Chief Executive Officer or by our board of directors pursuant to a resolution adopted by a majority of the total number of authorized directors (whether or not there exists any vacancies); and	
 
 	•	 	provide that the Court of Chancery of the State of Delaware will be the sole and exclusive forum for (1) any derivative action or proceeding brought on its behalf, (2) any action asserting a claim of breach of a fiduciary duty owed by any of its directors or officers to its or its stockholders, (3) any action asserting a claim against it arising pursuant to any provision of the DGCL or its amended and restated certificate of incorporation or amended and restated bylaws, or (4) any action asserting a claim against it governed by the internal affairs doctrine.	
The amendment of any of these provisions, with the exception of the ability of our board of directors to issue shares of preferred stock and designate any rights, preferences and privileges thereto, would require the affirmative vote of the holders of at least 66 2/3% of the voting power of all of the outstanding Forte common stock.
Transfer Agent and Registrar
The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar’s address is 250 Royall Street, Canton, Massachusetts 02021.
Listing on the Nasdaq Capital Market
Our common stock is listed on the Nasdaq Capital Market under the symbol “FBRX”.
 
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PLAN OF DISTRIBUTION
We have entered into the sales agreement with Ladenburg, under which we may issue and sell from time to time shares of our common stock having an aggregate offering price of up to $30,000,000 through Ladenburg as our sales agent. Sales of the common stock, if any, will be made by any method permitted by law deemed to be an “at the market offering” as defined in Rule 415 promulgated under the Securities Act, or in privately negotiated transactions. Ladenburg will offer our common stock at prevailing market prices subject to the terms and conditions of the sales agreement as agreed upon by us and Ladenburg. We will designate the number of shares which we desire to sell, the time period during which sales are requested to be made, any limitation on the number of shares that may be sold in one day and any minimum price below which sales may not be made. Subject to the terms and conditions of the sales agreement, Ladenburg will use its commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us. We or Ladenburg may suspend the offering of the common stock being made through Ladenburg under the sales agreement upon proper notice to the other party.
Ladenburg will provide written confirmation to us no later than the trading day after each day on which common stock is sold through it as sales agent under the sales agreement. Each confirmation will include the number of shares of common stock sold through it as sales agent on that day, the gross sales price per share, the net proceeds to us and the compensation payable by us to Ladenburg.
Settlement for sales of common stock will occur on the second business day or such shorter settlement cycle as may be in effect under Exchange Act Rule 15c6-1 from time to time, following the date on which any sales are made, or on some other date that is agreed upon by us and Ladenburg in connection with a particular transaction, in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.
We will pay Ladenburg in cash, upon each sale of our shares of common stock pursuant to the sales agreement, a commission equal to 3.0% of the gross proceeds from each sale of shares of our common stock. Ladenburg may effect sales to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from Ladenburg and/or purchasers of shares of common stock for whom they may act as agents or to whom they may sell as principal. Because there is no minimum offering amount required as a condition to this offering, the actual total public offering amount, commissions and proceeds to us, if any, are not determinable at this time. Pursuant to the terms of the sales agreement, we agreed to reimburse Ladenburg for the documented fees and costs of its legal counsel up to $40,000. Additionally, pursuant to the terms of the sales agreement, at the end of each calendar quarter during the term of the sales agreement, we have agreed to reimburse Ladenburg up to $4,000 for certain documented fees and costs of its legal counsel. We estimate that the total expenses of the offering payable by us, excluding commissions payable to Ladenburg under the sales agreement, will be approximately $160,000. The remaining sale proceeds, after deducting any other transaction fees, will equal our net proceeds from the sale of such shares.
We will report at least quarterly the number of shares of common stock sold through Ladenburg under the sales agreement, the net proceeds to us and the compensation paid by us to Ladenburg in connection with the sales of common stock.
In connection with the sales of the common stock on our behalf, Ladenburg may be deemed to be an “underwriter” within the meaning of the Securities Act, and the compensation paid to Ladenburg may be deemed to be underwriting commissions or discounts. We have agreed in the sales agreement to provide indemnification and contribution to Ladenburg against certain liabilities, including liabilities under the Securities Act.
The offering of our shares of common stock pursuant to the sales agreement will terminate as permitted therein, including upon the earlier of the (i) sale of all of our shares of common stock provided for in this prospectus supplement, or (ii) termination of the sales agreement as permitted therein. We and Ladenburg may each terminate the sales agreement at any time upon 10 days’ prior notice.
 
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Ladenburg and its affiliates may in the future provide various investment banking and other financial services for us and our affiliates, for which services they may in the future receive customary fees. To the extent required by Regulation M, Ladenburg will not engage in any market making activities involving our shares of common stock while the offering is ongoing under this prospectus supplement. This summary of the material provisions of the sales agreement does not purport to be a complete statement of its terms and conditions. We are filing a copy of the sales agreement with the SEC on a Current Report on Form 8-K concurrently with the filing of this prospectus supplement.
This prospectus supplement and the accompanying prospectus in electronic format may be made available on a website maintained by Ladenburg, and Ladenburg may distribute this prospectus supplement and the accompanying prospectus electronically.
LEGAL MATTERS
The validity of the securities offered hereby will be passed upon for us by Wilson Sonsini Goodrich & Rosati Professional Corporation, San Diego, California. Ladenburg Thalmann & Co. Inc., is being represented in connection with this offering by Mintz, Levin, Cohn, Ferris, Glovsky and Popeo, P.C., New York, NY.
EXPERTS
Forte Subsidiary, Inc. (formerly Forte Biosciences, Inc.)
The financial statements of Forte Subsidiary, Inc. as of and for the years ended December 31, 2019 and 2018 included in the Form S-4/A (Registration No. 333-237371) filed with the SEC on May 13, 2020, and on Form 8-K filed with the SEC on September 4, 2020, have been audited by Mayer Hoffman McCann P.C., independent registered public accounting firm, as set forth in their report included therein and have been incorporated by reference in this Prospectus Supplement 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.
Forte Biosciences, Inc. (formerly Tocagen Inc.)
Ernst & Young LLP, independent registered public accounting firm, has audited our financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2019, as set forth in their report thereon (which contains an explanatory paragraph describing conditions that raise substantial doubt about the Company’s ability to continue as a going concern as described in Note 1 to the financial statements) which is incorporated by reference in this prospectus supplement 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.
WHERE YOU CAN FIND ADDITIONAL INFORMATION
This prospectus supplement and the accompanying prospectus do not contain all of the information set forth in this registration statement and the exhibits to this registration statement or the documents incorporated by reference herein and therein. For further information with respect to us and the securities that we are offering under this prospectus supplement, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement and the documents incorporated by reference herein and therein. You should rely only on the information contained in this prospectus supplement or the accompanying prospectus or incorporated by reference herein or therein. We have not authorized anyone else to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You
 
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should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus supplement, regardless of the time of delivery of this prospectus supplement or any sale of the securities offered hereby.
We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at http://www.sec.gov.
We make available, free of charge, through our investor relations website, our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, statements of changes in beneficial ownership of securities and amendments to those reports and statements as soon as reasonably practicable after they are filed with the SEC. The address for our website is https://www.fortebiorx.com The contents on our website are not part of this prospectus supplement, and the reference to our website does not constitute incorporation by reference into this prospectus supplement of the information contained at that site.
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
The SEC allows us to “incorporate by reference” into this prospectus supplement the information we file with the SEC. This means that we can disclose important information to you by referring you to those documents. Any statement contained in a document incorporated by reference in this prospectus supplement shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein, or in any subsequently filed document, which also is incorporated by reference herein, modifies or supersedes such earlier statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.
We hereby incorporate by reference into this prospectus supplement the following documents (other than the portions of these documents deemed to be “furnished” or not deemed to be “filed,” including the portions of these documents that are furnished under Item 2.02 or Item 7.01 of a Current Report on Form 8-K, including any exhibits included with such Items):
 
 	•	 	our Annual Report on Form 10-K for the fiscal year ended December 31, 2019, filed with the SEC on February  27, 2020, as amended on April 29, 2020 (the “Annual Report”);	
 
 	•	 	our Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2020 and June 30, 2020, filed with the SEC on April  23, 2020 and August 10, 2020, respectively (the “Quarterly Reports”);	
 
 	•	 	our Current Reports on Form 8-K filed with the SEC on September 4, 2020; August  10, 2020 (two filings, one amended from an original filing date of June  15, 2020); July 21, 2020; June 26, 2020;  June 15, 2020;  June 12, 2020; June 8, 2020;  May 1, 2020; April 23, 2020; April 15, 2020;  February 27, 2020;  February 21, 2020; and February  20, 2020 (two filings); and	
 
 	•	 	our prospectus dated May  14, 2020, filed with the Securities and Exchange Commission pursuant to Rule 424(b) under the Securities Act, relating to the Registration Statement on Form S-4, as amended (File No. 333-237371), which includes a proxy statement filed pursuant to Section 14 of the Securities Exchange Act.	
All documents that we file with the SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act (other than current reports on Form 8-K, or portions thereof, furnished under Items 2.02 or 7.01 of Form 8-K) (i) after the initial filing date of the registration statement of which this prospectus supplement forms a part and prior to the effectiveness of such registration statement and (ii) after the date of this prospectus supplement and prior to the termination of this offering shall be deemed to be incorporated by reference in this prospectus supplement from the date of filing of the documents, unless we specifically provide otherwise. Information that we file with the SEC will automatically update and may replace information previously filed with the SEC. To
 
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the extent that any information contained in any current report on Form 8-K or any exhibit thereto, was or is furnished to, rather than filed with the SEC, such information or exhibit is specifically not incorporated by reference.
Upon written or oral request made to us at the address or telephone number below, we will, at no cost to the requester, provide to each person, including any beneficial owner, to whom this prospectus supplement is delivered, a copy of any or all of the information that has been incorporated by reference in this prospectus supplement (other than an exhibit to a filing, unless that exhibit is specifically incorporated by reference into that filing), but not delivered with this prospectus supplement. You may also access this information on our website at www.fortebiorx.com by viewing the “SEC Filings” subsection of the “Investor Relations” menu. No additional information on our website is deemed to be part of or incorporated by reference into this prospectus supplement. We have included our website address in this prospectus supplement solely as an inactive textual reference.
Forte Biosciences, Inc.
1124 W Carson Street
MRL Building 3-320
Torrance, California 90502
Attn: Investor Relations
Tel: (310) 618-6994
 
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PROSPECTUS

$100,000,000
Common Stock
Preferred Stock
Debt Securities
Warrants

From time to time, we may offer up to $100,000,000 of any combination of the securities described in this prospectus in one or more offerings. We may also offer securities as may be issuable upon conversion, redemption, repurchase, exchange or exercise of any securities registered hereunder, including any applicable antidilution provisions.
This prospectus provides a general description of the securities we may offer. Each time we offer 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 supplement and any related free writing prospectus may also add, update or change information contained in this prospectus. You should carefully read this prospectus, the applicable prospectus supplement and any related free writing prospectus, as well as any documents incorporated by reference, before you invest in any of the securities being offered.

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

Our common stock is traded on the Nasdaq Global Select Market under the symbol “TOCA.” On May 22, 2018, the last reported sales price of our common stock was $9.52 per share. The applicable prospectus supplement will contain information, where applicable, as to any other listing on the Nasdaq Global Select Market or any securities market or other exchange of the securities, if any, covered by the prospectus supplement.
We will sell these securities directly to investors, through agents designated from time to time or to or through underwriters or dealers, on a continuous or delayed basis. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any agents or underwriters are involved in the sale of any securities with respect to which this prospectus is being delivered, the names of such agents or underwriters and any applicable fees, commissions, discounts or over-allotment options will be set forth in a prospectus supplement. The 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.
Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus.
NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

The date of this prospectus is May 23, 2018.

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TABLE OF CONTENTS

ABOUT THIS PROSPECTUS	  	 	i	 	
SUMMARY	  	 	1	 	
RISK FACTORS	  	 	6	 	
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS	  	 	7	 	
RATIO OF EARNINGS TO FIXED CHARGES	  	 	8	 	
USE OF PROCEEDS	  	 	8	 	
DESCRIPTION OF CAPITAL STOCK	  	 	8	 	
DESCRIPTION OF DEBT SECURITIES	  	 	12	 	
DESCRIPTION OF WARRANTS	  	 	19	 	
LEGAL OWNERSHIP OF SECURITIES	  	 	21	 	
PLAN OF DISTRIBUTION	  	 	24	 	
LEGAL MATTERS	  	 	26	 	
EXPERTS	  	 	26	 	
WHERE YOU CAN FIND MORE INFORMATION	  	 	26	 	
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE	  	 	27	 	
DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITY	  	 	28	 	

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ABOUT THIS PROSPECTUS
This prospectus is a part of a registration statement on Form S-3 that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total aggregate offering price of $100,000,000. This prospectus provides you with a general description of the securities we may offer.
Each time we sell securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the 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 or in any documents that we have incorporated by reference into this prospectus. You should read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading “Incorporation of Certain Information by Reference,” before investing in any of the securities offered.
THIS PROSPECTUS MAY NOT BE USED TO CONSUMMATE A SALE OF SECURITIES UNLESS IT IS ACCOMPANIED BY A PROSPECTUS SUPPLEMENT.
Neither we, nor any agent, underwriter or dealer has authorized any person to give any information or to make any representation other than those contained or incorporated by reference in this prospectus, any applicable prospectus supplement or any related free writing prospectus prepared by or on behalf of us or to which we have referred you. This prospectus, any applicable supplement to this prospectus or any related free writing prospectus 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, any applicable supplement to this prospectus or any related free writing prospectus 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 contained in this prospectus, any applicable prospectus supplement or any related free writing prospectus is accurate on any date subsequent to the date set forth on the front of the document or that any information we have incorporated by reference is correct on any date subsequent to the date of the document incorporated by reference, even though this prospectus, any applicable prospectus supplement or any related free writing prospectus is delivered, or securities are sold, on a later date.
This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or will be incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading “Where You Can Find More Information.
 
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SUMMARY
This summary highlights selected information from this prospectus and does not contain all of the information that you need to consider in making your investment decision. You should carefully read the entire prospectus, the applicable prospectus supplement and any related free writing prospectus, including the risks of investing in our securities discussed under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in the other documents that are incorporated by reference into this prospectus. You should also carefully read the information incorporated by reference into this prospectus, including our financial statements, and the exhibits to the registration statement of which this prospectus is a part.
Unless the context requires otherwise, references in this prospectus to the “Company,” “Tocagen,” “we,” “us” and “our” refer to Tocagen Inc.
Company Overview
We are a clinical-stage, cancer-selective gene therapy company focused on developing first-in-class, broadly-applicable product candidates designed to activate a patient’s immune system against their own cancer from within. Our cancer-selective gene therapy platform is built on retroviral replicating vectors, or RRVs, which are designed to selectively deliver therapeutic genes into the DNA of cancer cells. Our gene therapy approach is designed to fight cancer through immunotherapeutic mechanisms of action without the autoimmune toxicities commonly experienced with other immunotherapies. Our founding vision is “No One Should Die Of Cancer” because we believe the immune system can be safely activated to fight the patient’s cancer.
We are developing our lead product candidate, Toca 511 (vocimagene amiretrorepvec) & Toca FC (extended-release flucytosine), initially for the treatment of recurrent high grade glioma, or HGG, a brain cancer with limited treatment options, low survival rates and, therefore, a significant unmet medical need. We are conducting a randomized, controlled Phase 3 clinical trial of Toca 511 & Toca FC in patients with recurrent HGG, or the Toca 5 trial, which is designed to serve as a registrational trial. In February 2017, the U.S. Food and Drug Administration, or FDA, granted Toca 511 & Toca FC Breakthrough Therapy Designation for the treatment of patients with recurrent HGG and in June 2017 the European Medicines Agency, or EMA, granted Toca 511 Priority Medicines, or PRIME, Designation for the treatment of patients with glioma. Breakthrough Therapy Designation indicates that preliminary clinical evidence demonstrates the drug may have substantial improvement on one or more clinically significant endpoints over available therapy. PRIME Designation indicates that there is a potential to benefit patients with unmet medical needs based on early clinical data. We also have Fast Track Designation (which may lead to expedited regulatory review of new products that treat serious diseases or conditions and demonstrate the potential to address an unmet medical need) from the FDA for Toca 511 & Toca FC for the treatment of recurrent HGG. We also received Orphan-Drug Designation from the FDA for the treatment of HGG. Orphan-Drug Designation is a designation for a product that treats a rare disease or condition and which, if the product receives the first FDA approval for that disease or condition, may result in a period of regulatory exclusivity, subject to some exceptions. The Committee for Orphan Medicinal Products of the EMA has designated both flucytosine and vocimagene amiretrorepvec as orphan medicinal products indicated for the treatment of glioma. The EMA provides several benefits to drug developers for developing drugs for orphan diseases.
We have conducted three ascending dose Phase 1 clinical trials involving 127 recurrent HGG patients. In these trials, we investigated three modes of Toca 511 delivery: injection into the cavity wall after surgical resection of the recurred tumor (n=56), direct intratumoral injection without resection (n=54), and intravenous administration followed, approximately one to two weeks later, by resection with further local vector delivery at the time of resection (n=17). Administration of Toca 511 was followed with cycles of Toca FC. In these trials, we observed potential benefits, including durable objective responses, extended overall survival compared to
 
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historical controls and a favorable safety profile. We did not reach a dose-limiting toxicity in any of these trials. Based on these Phase 1 clinical trial results, we are conducting a Phase 3 clinical trial, called the Toca 5 trial, which is designed to serve as a potential registrational trial in patients with first or second recurrent HGG undergoing resection.
As of the data cutoff of December 2017, of the 56 patients enrolled in the ascending-dose resection injection Phase 1 trial, 53 were efficacy evaluable and of those, six patients had a complete response, or CR, and remain in response. All six CR’s were in the higher dose cohorts of the trial. Five of these patients with a CR were within a subset of 23 patients that mirrors the entry criteria, clinical setting and dosing for patients in the Toca 5 trial. Responses were assessed by independent radiology review of magnetic resonance imaging brain scans. Median duration of response had not been reached after a median follow-up of 36.5 months (range: 9.2 to 44.9 months) which compares favorably to a range of durable responses of 2.79 to 9.62 months in a clinical trial of a drug used as standard of care for recurrent HGG. An association between durable response and overall survival is suggested as all responders remain alive following study entry (range: 38.0 to 57.5 months). As of the data cutoff of December 2017, the subset of 23 patients in our Phase 1 resection injection trial that mirrors the Toca 5 patient population (similar entry criteria, clinical setting and dosing) had a median survival of 14.4 months, with an approximately six-month improvement in median overall survival relative to results from clinical trials of drugs used as standard of care for recurrent HGG. In addition:
 
 	•	 	Five of 23 patients had a durable CR, bringing the durable response rate (objective responses lasting at least 24 weeks) to 21.7%.	
 
 	•	 	Median duration of response had not been reached after a median follow up of 37.4 months (range: 16.8 to 44.9 months).	
 
 	•	 	Stable disease (lasting at least eight weeks) was observed in five additional patients, bringing the clinical benefit rate to 43.5% (10/23 patients).	
 
 	•	 	Landmark overall survival, or OS, rates at two and three years (OS24, OS36) was 34.8% and 26.1%, respectively.	
Increases in immunologic activity during treatment were observed with Toca 511 & Toca FC treatment, including elevations of replicating CD4 (often referred to as “helper” T cells) and CD8 (often referred to as “killer” T cells) T cells in the blood, for patients in some cohorts in the resection injection Phase 1 trial.
Based on our findings in preclinical studies and clinical trials to date, we believe Toca 511 & Toca FC is a promising candidate for use in newly diagnosed HGG patients in combination with surgery, radiation and chemotherapy. Therefore, we plan to advance clinical development to evaluate safety and efficacy in this setting with Toca 511 & Toca FC being delivered in conjunction with surgery, radiation and temozolomide.
Based on preclinical data, we believe Toca 511 & Toca FC may also have therapeutic benefit in multiple other solid tumor cancers. Furthermore, in our completed Phase 1 intravenous clinical trial of Toca 511 for the treatment of recurrent HGG, Toca 511 crossed the blood brain barrier and was detected in brain tumors. We therefore initiated a Phase 1b clinical trial, or the Toca 6 trial, in July 2016 of intravenous treatment of advanced cancers that include colorectal, pancreatic, breast, and lung cancers, all of which can spread to the brain and other organs. In the Phase 1b trial, Toca 511 will be administered by intravenous injection followed at 8-11 days later by biopsy then local delivery. In our Toca 6 trial we plan to evaluate safety, presence of Toca 511 genes in tumors, immunologic activity in the blood and tumor such as changes in CD4 and CD8 T cells and clinical activity such as objective tumor response and clinical benefit. We have observed Toca 511 genes and proteins in tumor biopsies following Toca 511 intravenous infusions.
Our RRV platform is versatile and we believe it has the potential to deliver a wide variety of genes selectively to cancer cells. Our first RRV-based immunotherapy product candidate, Toca 511 & Toca FC, is designed to replicate without cell lysis then directly kill cancer and immune suppressive myeloid cells activating
 
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the immune system against cancer through a combination of mechanisms. In addition, we are developing other RRVs to selectively deliver genes to cancer cells against validated immunotherapy targets, such as the checkpoint protein PD-L1. We generated preclinical data supporting the potential anti-cancer benefits of an RRV delivering a gene against PD-L1. In 2018, we plan to initiate IND-enabling studies of our anti-PD-L1 RRV product candidate.
Cancer is the second leading cause of mortality in the United States and accounts for nearly one in four deaths. Early cancer treatments relied on relatively non-specific and highly toxic small molecule chemotherapies. Over the last 20 years, a new paradigm of cancer research and treatment has emerged that is focused on more targeted therapies. Most recently this has included the emergence of immunotherapies that can stimulate a patient’s immune system to slow the growth and the spread of, and ideally, eliminate cancer cells. These therapies have shown the potential to provide dramatic efficacy and to extend survival for cancer patients even in cases in which conventional therapies, such as surgery, chemotherapy and radiotherapy, have already been used. In 2013, Science magazine named cancer immunotherapy as the biggest breakthrough of the year. With this breakthrough, global pharmaceutical companies as well as a large number of emerging companies are researching and developing new cancer immunotherapy treatments.
Despite these advancements, many current immunotherapies, such as checkpoint inhibitors, chimeric antigen receptor and T cell receptor T cells, are limited by their autoimmune and other side effects. Combination treatments are common in cancer, but combinations of immune mediated treatments with systemic cytotoxic chemotherapy may be challenging as chemotherapy is often damaging to the immune system. Thus, immunotherapies effective enough to be able to displace systemic chemotherapy are needed. The utility of oncolytic viruses alone as immunotherapy has been challenged by lack of specificity to tumor cells, injury to healthy tissues, lack of targeting to specific brakes on the immune system, and short-term effect due to effective clearance of the virus. Consequently, there remains a significant need for immunotherapies that are effective as well as safe and tolerable.
In contrast to current immunotherapies, we believe our RRV platform and lead product candidate have the potential to selectively infect cancer cells and subsequently, after 5-FC administration, to stimulate robust and durable anti-cancer immune responses with minimal toxicity. Our RRVs are designed to selectively integrate into the DNA of cancer cells which then serve as factories to produce more of these RRVs by budding. The progeny RRV infect neighboring cancer cells, providing long-term presence of the therapeutic gene or genes. Our novel therapies are designed to break immune tolerance selectively in the tumor microenvironment.
Toca 511 & Toca FC is designed to break immune tolerance through a combination of mechanisms triggered by the conversion of Toca FC into high levels of 5-FU (5-fluorouracil), an anti-cancer agent, directly in tumors. Conversion of Toca FC to 5-FU is catalyzed by the enzyme encoded by the therapeutic gene delivered by Toca 511 into the cancer cell. Toca 511 & Toca FC treatment is designed for cycles of sustained production of high levels of 5-FU directly in tumors, which we believe is important for robust and durable anti-cancer immune activation. Cancer cell death releases damage-associated molecular patterns, pathogen-associated molecular patterns, and tumor-associated antigens, resulting in antigen presentation and activation of T cells. 5-FU is known to kill cancer cells and immune cells when used systemically. When 5-FU is present locally, it kills immune-suppressive myeloid cells in the tumor micro-environment while leaving systemic immune activity clinically intact. The local immune-suppressive myeloid cells include myeloid-derived suppressor cells, or MDSCs, as well as tumor associated macrophages, or TAMs, which are white blood cells recruited and retained by the tumor that contribute to the suppression of normal immune activity against cancer cells. TAMs and MDSCs suppress the number and activity of CD4 and CD8 T cells and work with the lymphocyte-derived suppressor T cells called regulatory T cells. MDSC and TAM destruction by 5-FU is designed to contribute to immune activation against the tumor-associated antigens. We believe the persistence of the therapeutic gene in the cancer cells has allowed for multiple cycles of Toca FC treatment in our trials, which may result in additional killing of cancer cells and immunosuppressive myeloid cells, leading to enhancement of the strength and durability of the immune response with each successive cycle of Toca FC treatment. Also, in a trial with multiple
 
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Toca 511 intravenous infusions followed by resection, we observed increased Toca 511 in the tumor compared to single day infusion.
We have entered into selected partnerships for the development and commercialization of our technology and products. We have entered into a license agreement with Beijing Apollo Venus Biomedical Technology Limited and ApolloBio Corp., or collectively ApolloBio, pursuant to which we granted to ApolloBio an exclusive license to develop and commercialize Toca 511 & Toca FC within the greater China region, including mainland China, Hong Kong, Macao and Taiwan. Under the license agreement, we are eligible to receive up to $127 million in upfront payment, development and commercial milestones, plus additional double-digit tiered sales royalties. The upfront and near-term development milestone payments total up to $20 million. We have licensed rights to, and collaborate with, Siemens Healthcare Diagnostics Inc. to develop diagnostics related to the clinical development and future commercialization of Toca 511 & Toca FC. We have intellectual property protection in major markets worldwide, including 76 issued and granted patents and 72 patent applications (foreign and domestic) on our technology platform and novel product candidates, which we believe will maintain coverage from issued patents until approximately 2030. Since inception in 2007, we have funded our operations primarily through the sales of our equity securities from which we received $230.2 million in net proceeds.
Corporate Information
We were incorporated in Delaware in August 2007. Our principal executive offices are located at 3030 Bunker Hill Street, Suite 230, San Diego, California 92109. Our telephone number is (858) 412-8400. Our corporate website address is www.tocagen.com. Information contained on or accessible through our website is not a part of this prospectus, and the inclusion of our website address in this prospectus is an inactive textual reference only.
This prospectus contains references to our trademarks and to trademarks belonging to other entities. Solely for convenience, trademarks and trade names referred to in this prospectus, including logos, artwork and other visual displays, may appear without the ® or TM symbols, but such references are not intended to indicate, in any way, that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend our use or display of other companies’ trade names or trademarks to imply a relationship with, or endorsement or sponsorship of us by, any other companies.
The 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, up to a total aggregate offering price of $100,000,000 from time to time in one or more offerings under this prospectus, together with any applicable prospectus supplement and any related free writing prospectus, at prices and on terms to be determined by market conditions at the time of the relevant 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 under this prospectus, 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:
 
 	•	 	designation or classification;	
 
 	•	 	aggregate principal amount or aggregate offering price;	
 
 	•	 	maturity, if applicable;	
 
 	•	 	original issue discount, if any;	
 
 	•	 	rates and times of payment of interest or dividends, if any;	
 
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 	•	 	redemption, conversion, exchange or sinking fund terms, if any;	
 
 	•	 	conversion or exchange prices or rates, if any, and, if applicable, any provisions for changes to or adjustments in the conversion or exchange prices or rates and in the securities or other property receivable upon conversion or exchange;	
 
 	•	 	ranking, if applicable;	
 
 	•	 	restrictive covenants, if any;	
 
 	•	 	voting or other rights, if any; and	
 
 	•	 	important U.S. federal income tax considerations.	
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 or in documents we have 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.
This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.
We may sell the securities directly to investors 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 do offer securities through underwriters or agents, we will include in the applicable prospectus supplement:
 
 	•	 	the names of those underwriters or agents;	
 
 	•	 	applicable fees, discounts and commissions to be paid to them;	
 
 	•	 	details regarding over-allotment options, if any; and	
 
 	•	 	the estimated net proceeds to us.	
Common Stock. We may issue shares of our common stock from time to time. Holders of our common stock are entitled to one vote per share for the election of directors and on all other matters that require stockholder approval. Subject to any preferential rights of any then outstanding preferred stock, in the event of our liquidation, dissolution or winding up, holders of our common stock are entitled to share ratably in the assets remaining after payment of liabilities and the liquidation preferences of any then outstanding preferred stock. Our common stock does not carry any preemptive rights enabling a holder to subscribe for, or receive shares of, any class of our common stock or any other securities convertible into shares of any class of our common stock, or any redemption rights.
Preferred Stock. We may issue shares of our preferred stock from time to time, in one or more series. Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 10,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges, qualifications and restrictions granted to or imposed upon the preferred stock, including dividend rights, conversion rights, voting rights, rights and terms of redemption, liquidation preference and sinking fund terms, any or all of which may be greater than the rights of the common stock. To date, none of the 10,000,000 authorized shares of preferred stock have been designated by our board of directors. Convertible preferred stock will be convertible into our common stock or exchangeable for our other securities. Conversion may be mandatory or at the option of the holders of our preferred stock and would be at prescribed conversion rates.
We will fix the rights, preferences, privileges, qualifications and restrictions of the preferred stock of each series that we sell under this prospectus and applicable prospectus supplements in the certificate of designation
 
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relating to that series. We will incorporate by reference into the registration statement of which this prospectus is a part the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. We urge you, however, to read the applicable prospectus supplement (and any related free writing prospectus that we may authorize to be provided to you) related to the series of preferred stock being offered, as well as the complete certificate of designation that contains the terms of the applicable series of preferred stock.
Debt Securities. We may issue 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 unsecured and unsubordinated debt. 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 of our senior indebtedness. Convertible debt securities will be convertible into our common stock or preferred stock. 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 national banking association or other eligible party, as trustee. In this prospectus, we have summarized certain general features of the debt securities. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the series of debt securities being offered, as well as the complete indentures that contain the terms of the debt securities. A form of indenture has been filed as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.
Warrants. We may issue warrants for the purchase of 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 these securities. In this prospectus, we have summarized certain general features of the warrants. We urge you, however, to read the applicable prospectus supplement (and any free writing prospectus that we may authorize to be provided to you) related to the particular series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the warrants. Forms of the warrant agreements and forms of warrant certificates containing the terms of the warrants being offered have been filed as exhibits to the registration statement of which this prospectus is a part, and supplemental warrant agreements and forms of warrant certificates will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.
We will evidence each series of warrants by warrant certificates that we will issue. Warrants may be issued under an applicable warrant agreement that we enter into with a warrant agent. We will indicate the name and address of the warrant agent, if applicable, in the prospectus supplement relating to the particular series of warrants being offered.
RISK FACTORS
Investing in our securities involves a high degree of risk. You should carefully review the risks and uncertainties described under the heading “Risk Factors” contained in the applicable prospectus supplement and any related free writing prospectus, and under similar headings in our Annual Report on Form 10-K for the year ended December 31, 2017, as updated by our annual, quarterly and other reports and documents that are incorporated by reference into this prospectus, before deciding whether to purchase any of the securities being registered pursuant to the registration statement of which this prospectus is a part. Each of the risk factors could adversely affect our business, operating results and financial condition, as well as adversely affect the value of an investment in our securities, and the occurrence of any of these risks might cause you to lose all or part of your
 
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investment. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations.
SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS
This prospectus, each prospectus supplement and the information incorporated by reference in this prospectus and each prospectus supplement contain forward-looking statements within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act of 1934, as amended, or the Exchange Act, that involve a number of risks and uncertainties. Although our forward-looking statements reflect the good faith judgment of our management, these statements can only be based on facts and factors currently known by us. Consequently, these forward-looking statements are inherently subject to risks and uncertainties, and actual results and outcomes may differ materially from results and outcomes discussed in the forward-looking statements.
Forward-looking statements can be identified by the use of forward-looking words such as “believes,” “expects,” “hopes,” “may,” “will,” “plan,” “intends,” “estimates,” “could,” “should,” “would,” “continue,” “seeks,” “pro forma,” or “anticipates,” or other similar words (including their use in the negative), or by discussions of future matters such as the development of new products, technology enhancements, possible collaborations and other statements that are not historical. These statements include but are not limited to statements under the captions “Business,” “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and in other sections incorporated by reference from our Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, as applicable, as well as our other filings with the SEC. You should be aware that the occurrence of any of the events discussed under the heading “Risk Factors” in any applicable prospectus supplement and any documents incorporated by reference herein or therein could substantially harm our business, operating results and financial condition and that if any of these events occurs, it could adversely affect the value of an investment in our securities.
The cautionary statements made in this prospectus are intended to be applicable to all related forward-looking statements wherever they may appear in this prospectus or in any prospectus supplement or any documents incorporated by reference herein or therein. We urge you not to place undue reliance on these forward-looking statements, which speak only as of the date they are made. Except as required by law, we assume no obligation to update our forward-looking statements, even if new information becomes available in the future.
 
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RATIO OF EARNINGS TO FIXED CHARGES
The following table sets forth our ratio of earnings to fixed charges and the ratio of our combined fixed charges and preferred dividends to earnings for each of the periods indicated. The following table is qualified by the more detailed information appearing in the computation table set forth in Exhibit 12.1 to the registration statement of which this prospectus is part and the historical financial statements, including the notes to those financial statements, incorporated by reference in this prospectus. We have paid no dividends on preferred shares during the periods indicated. Therefore, the ratios of earnings to combined fixed charges and preferred dividends are the same as the ratio of earnings to fixed charges.

 	  	Year Ended December 31,	 	  	Three Months
Ended
March 31,	 	
 	  	2015	 	  	2016	 	  	2017	 	  	2018	 	
 	  	 	 	  	(in thousands)	 	
Ratio of earnings to fixed charges	  	 	N/A	 	  	 	N/A	 	  	 	N/A	 	  	 	N/A	 	
Ratio of earnings to combined fixed charges and preferred stock dividends	  	 	N/A	 	  	 	N/A	 	  	 	N/A	 	  	 	N/A	 	
Deficiency of earnings available to cover fixed charges	  	$	(23,056	) 	  	$	(33,478	) 	  	$	(38,929	) 	  	$	(12,880	) 	
Deficiency of earnings available to cover combined fixed charges and preferred stock dividends	  	$	(23,056	) 	  	$	(33,478	) 	  	$	(38,929	) 	  	$	(12,880	) 	
For purposes of computing the ratio of earnings to fixed charges and the ratio of our combined fixed charges and preferred stock dividends to earnings, earnings consist of income (loss) from continuing operations before income taxes plus fixed charges. Fixed charges consist of interest expense on indebtedness and an estimate of the interest within rental expense.
We did not record earnings for any of the years ended December 31, 2015, 2016, and 2017 or for the three months ended March 31, 2018. Accordingly, our earnings were insufficient to cover fixed charges for such periods and we are unable to disclose a ratio of earnings to fixed charges for such periods.
USE OF PROCEEDS
We will retain broad discretion over the use of the net proceeds from the sale of the securities offered hereby. Except as described in any prospectus supplement or any related free writing prospectus that we may authorize to be provided to you, we currently intend to use the net proceeds from the sale of the securities offered hereby for general corporate purposes, which may include research and development, capital expenditures, working capital and general and administrative expenses. We may also use a portion of the net proceeds to acquire or invest in businesses, products and technologies that are complementary to our own, although we have no current plans, commitments or agreements with respect to any acquisitions as of the date of this prospectus. We will set forth in the applicable prospectus supplement or free writing prospectus our intended use for the net proceeds received from the sale of any securities sold pursuant to the prospectus supplement or free writing prospectus. Pending these uses, we intend to invest the net proceeds in short- and intermediate-term, investment-grade, interest-bearing securities.
DESCRIPTION OF CAPITAL STOCK
As of the date of this prospectus, our amended and restated certificate of incorporation authorizes us to issue 200,000,000 shares of common stock, par value $0.001 per share and 10,000,000 shares of preferred stock, par value $0.001 per share. As of May 22, 2018, 19,912,983 shares of common stock were outstanding and no shares of preferred stock were outstanding. All of our authorized preferred stock is undesignated.
 
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The following is a summary of the rights of our common and preferred stockholders, of some of the provisions of our amended and restated certificate of incorporation and amended and restated bylaws and of the Delaware General Corporation Law, or DGCL. This summary is not complete. For more detailed information, please see our amended and restated certificate of incorporation and amended and restated bylaws, which are filed as exhibits to the registration statement of which this prospectus is a part, as well as the relevant provisions of the DGCL.
Common Stock
Voting. Our common stock is entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders, including the election of directors, and does not have cumulative voting rights. Accordingly, the holders of a majority of the shares of our common stock entitled to vote in any election of directors can elect all of the directors standing for election.
Dividends. Subject to preferences that may be applicable to any then-outstanding preferred stock, the holders of common stock are entitled to receive dividends, if any, as may be declared from time to time by our board of directors out of legally available funds.
Liquidation. In the event of our liquidation, dissolution or winding-up, holders of our common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities, subject to the satisfaction of any liquidation preference granted to the holders of any outstanding shares of preferred stock.
Rights and Preferences. Holders of our common stock have no preemptive, conversion or subscription rights, and there are no redemption or sinking fund provisions applicable to our common stock. The rights, preferences and privileges of the holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any series of our preferred stock that we may designate and issue in the future.
Preferred Stock
Under our amended and restated certificate of incorporation, our board of directors has the authority, without further action by stockholders, to designate up to 10,000,000 shares of preferred stock in one or more series and to fix or alter, from time to time, the designations, powers and rights of each series of preferred stock and the qualifications, limitations or restrictions of any series of preferred stock, including dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption (including sinking fund provisions), redemption price or prices, and the liquidation preference of any wholly unissued series of preferred stock, any or all of which may be greater than the rights of the common stock, and to establish the number of shares constituting any such series. To date, none of the 10,000,000 authorized shares of preferred stock have been designated by our board of directors.
Our board of directors will fix the rights, preferences, privileges, qualifications and restrictions of the preferred stock of each series that we sell under this prospectus and any applicable prospectus supplements in the certificate of designation relating to each such series. We will incorporate by reference as an exhibit to the registration statement of which this prospectus is a part or as an exhibit to one or more Current Reports on Form 8-K, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. This description will include:
 
 	•	 	the title and stated value;	
 
 	•	 	the number of shares we are offering;	
 
 	•	 	the liquidation preference per share;	
 
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 	•	 	the purchase price per share;	
 
 	•	 	the dividend rate per share, dividend period, payment date or dates and method of calculation for dividends;	
 
 	•	 	whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;	
 
 	•	 	our right, if any, to defer payment of dividends and the maximum length of any such deferral period;	
 
 	•	 	the procedures for any auction and remarketing, if any;	
 
 	•	 	the provisions for a sinking fund, if any;	
 
 	•	 	the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;	
 
 	•	 	any listing of the preferred stock on any securities exchange or market;	
 
 	•	 	whether the preferred stock will be convertible into our common stock or other securities of ours, including warrants, and, if applicable, the conversion price, or how it will be calculated, and under what circumstances and the mechanism by which it may be adjusted, and the conversion period;	
 
 	•	 	whether the preferred stock will be exchangeable into debt securities or other securities of ours, and, if applicable, the exchange price, or how it will be calculated, and under what circumstances it may be adjusted, and the exchange period;	
 
 	•	 	voting rights, if any;	
 
 	•	 	preemptive rights, if any;	
 
 	•	 	restrictions on transfer, sale or other assignment, if any;	
 
 	•	 	whether interests in the preferred stock will be represented by depositary shares;	
 
 	•	 	a discussion of any material or special U.S. federal income tax considerations applicable to the preferred stock;	
 
 	•	 	the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;	
 
 	•	 	any limitations on issuances of any class or series of preferred stock ranking senior to or on parity with the series of preferred stock being issued as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and	
 
 	•	 	any other specific terms, rights, preferences, privileges, qualifications or limitations of, or restrictions on the preferred stock.	
If we issue and sell shares of preferred stock pursuant to this prospectus, together with any applicable prospectus supplement or free writing prospectus, the shares will be fully paid and nonassessable.
The laws of the state of Delaware, the state of our incorporation, provide that the holders of preferred stock will have the right to vote separately, as a class, on any proposal involving fundamental changes in the rights of holders of such preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.
The issuance of preferred stock could adversely affect the voting power, conversion or other rights of holders of common stock and reduce the likelihood that common stockholders will receive dividend payments and payments upon liquidation. Preferred stock could be issued quickly with terms designed to delay, deter or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of our common stock.
 
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Anti-Takeover Effects of Provisions of Our Amended and Restated Certificate of Incorporation, Our Bylaws and Delaware Law
Delaware Anti-Takeover Law
We are subject to Section 203 of the DGCL, which generally prohibits a public Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years after the date of the transaction in which the person became an interested stockholder, unless:
 
 	•	 	prior to the date of the transaction, the board of directors of the corporation approved either the business combination or the transaction which resulted in the stockholder becoming an interested stockholder;	
 
 	•	 	the interested stockholder owned at least 85% of the voting stock of the corporation outstanding upon consummation of the transaction, excluding for purposes of determining the number of shares outstanding (1) shares owned by persons who are directors and also officers and (2) shares owned by employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or	
 
 	•	 	on or subsequent to the consummation of the transaction, the business combination is approved by the board and authorized at an annual or special meeting of stockholders, and not by written consent, by the affirmative vote of at least 66 2/3% of the outstanding voting stock which is not owned by the interested stockholder.	
Section 203 of the DGCL defines a business combination to include:
 
 	•	 	any merger or consolidation involving the corporation and the interested stockholder;	
 
 	•	 	any sale, transfer, pledge or other disposition involving the interested stockholder of 10% or more of the assets of the corporation;	
 
 	•	 	subject to exceptions, any transaction involving the corporation that has the effect of increasing the proportionate share of the stock of any class or series of the corporation beneficially owned by the interested stockholder;	
 
 	•	 	subject to exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder; and	
 
 	•	 	the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges or other financial benefits provided by or through the corporation.	
In general, Section 203 of the DGCL defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by the entity or person.
Amended and Restated Certificate of Incorporation and Amended and Restated Bylaws
Provisions of our amended and restated certificate of incorporation and amended and restated bylaws, may delay or discourage transactions involving an actual or potential change in our control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares or transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these provisions could adversely affect the price of our common stock. Among other things, our amended and restated certificate of incorporation and amended and restated bylaws:
 
 	•	 	permit our board of directors to issue up to 10,000,000 shares of preferred stock, with any rights, preferences and privileges as they may designate;	
 
 	•	 	provide that the authorized number of directors may be changed only by resolution adopted by a majority of the board of directors;	
 
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 	•	 	provide that the board of directors or any individual director may only be removed with cause and the affirmative vote of the holders of at least 66 2/3% of the voting power of all of our then outstanding common stock;	
 
 	•	 	provide that all vacancies, including newly created directorships, may, except as otherwise required by law or subject to the rights of holders of preferred stock as designated from time to time, be filled by the affirmative vote of a majority of directors then in office, even if less than a quorum;	
 
 	•	 	divide our board of directors into three classes;	
 
 	•	 	require that any action to be taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and not be taken by written consent or electronic transmission;	
 
 	•	 	provide that stockholders seeking to present proposals before a meeting of stockholders or to nominate candidates for election as directors at a meeting of stockholders must provide notice in writing in a timely manner and also specify requirements as to the form and content of a stockholder’s notice;	
 
 	•	 	do not provide for cumulative voting rights (therefore allowing the holders of a majority of the shares of common stock entitled to vote in any election of directors to elect all of the directors standing for election, if they should so choose);	
 
 	•	 	provide that special meetings of our stockholders may be called only by the chairman of the board, our Chief Executive Officer or by the board of directors pursuant to a resolution adopted by a majority of the total number of authorized directors (whether or not there exists any vacancies); and	
 
 	•	 	provide that the Court of Chancery of the State of Delaware will be the sole and exclusive forum for (1) any derivative action or proceeding brought on our behalf, (2) any action asserting a claim of breach of a fiduciary duty owed by any of our directors or officers to us or our stockholders, (3) any action asserting a claim against the us arising pursuant to any provision of the DGCL or our certificate of incorporation or bylaws, or (4) any action asserting a claim against us governed by the internal affairs doctrine.	
The amendment of any of these provisions, with the exception of the ability of our board of directors to issue shares of preferred stock and designate any rights, preferences and privileges thereto, would require the affirmative vote of the holders of at least 66 2/3% of the voting power of all of our then outstanding common stock.
Transfer Agent and Registrar
The transfer agent and registrar for our common stock is Computershare Trust Company, N.A. The transfer agent and registrar’s address is 250 Royall Street, Canton, Massachusetts 02021. The transfer agent for any series of preferred stock that we may offer under this prospectus will be named and described in the prospectus supplement for that series.
Listing on the Nasdaq Global Select Market
Our common stock is listed on the Nasdaq Global Select Market under the symbol “TOCA”.
DESCRIPTION OF DEBT SECURITIES
We may issue debt securities from time to time, 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 debt securities that 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. The terms of any debt
 
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securities offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities.
We will issue the debt securities under the indenture that we will enter into with the trustee named in the indenture. The indenture will be qualified under the Trust Indenture Act of 1939, as amended, or the Trust Indenture Act. We have filed the form of indenture as an exhibit to the registration statement of which this prospectus is a part, and supplemental indentures and forms of debt securities containing the terms of the debt securities being offered will be filed as exhibits to the registration statement of which this prospectus is a part or will be incorporated by reference from reports that we file with the SEC.
The following summary of material provisions of the debt securities and the indenture is subject to, and qualified in its entirety by reference to, all of the provisions of the indenture applicable to a particular series of debt securities. We urge you to read the applicable prospectus supplements and any related free writing prospectuses related to the debt securities that we may offer under this prospectus, as well as the complete indenture that contains the terms of the debt securities.
General
The indenture does not limit the amount of debt securities that we may issue. It provides that we may issue debt securities up to the principal amount that we may authorize and may be in any currency or currency unit that we may designate. Except for the limitations on consolidation, merger and sale of all or substantially all of our assets contained in the indenture, the terms of the indenture do not contain any covenants or other provisions designed to give holders of any debt securities protection against changes in our operations, financial condition or transactions involving us.
We may issue the debt securities issued under the indenture as “discount securities,” which means they may be sold at a discount below their stated principal amount. These debt securities, as well as other debt securities that are not issued at a discount, may be issued with “original issue discount,” or OID, for U.S. federal income tax purposes because of interest payment and other characteristics or terms of the debt securities. Material U.S. federal income tax considerations applicable to debt securities issued with OID will be described in more detail in any applicable prospectus supplement.
We will describe in the applicable prospectus supplement the terms of the series of debt securities being offered, including:
 
 	•	 	the title of the series of debt securities;	
 
 	•	 	any limit upon the aggregate principal amount that may be issued;	
 
 	•	 	the maturity date or dates;	
 
 	•	 	the form of the debt securities of the series;	
 
 	•	 	the applicability of any guarantees;	
 
 	•	 	whether or not the debt securities will be secured or unsecured, and the terms of any secured debt;	
 
 	•	 	whether the debt securities rank as senior debt, senior subordinated debt, subordinated debt or any combination thereof, and the terms of any subordination;	
 
 	•	 	if the price (expressed as a percentage of the aggregate principal amount thereof) at which such debt securities will be issued is a price other than the principal amount thereof, the portion of the principal amount thereof payable upon declaration of acceleration of the maturity thereof, or if applicable, the portion of the principal amount of such debt securities that is convertible into another security or the method by which any such portion shall be determined;	
 
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 	•	 	the interest rate or rates, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;	
 
 	•	 	our right, if any, to defer payment of interest and the maximum length of any such deferral period;	
 
 	•	 	if applicable, the date or dates after which, or the period or periods during which, and the price or prices at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemption provisions;	
 
 	•	 	the date or dates, if any, on which, and the price or prices at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;	
 
 	•	 	the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;	
 
 	•	 	any and all terms, if applicable, relating to any auction or remarketing of the debt securities of that series and any security for our obligations with respect to such debt securities and any other terms which may be advisable in connection with the marketing of debt securities of that series;	
 
 	•	 	whether the debt securities of the series shall be issued in whole or in part in the form of a global security or securities; the terms and conditions, if any, upon which such global security or securities may be exchanged in whole or in part for other individual securities; and the depositary for such global security or securities;	
 
 	•	 	if applicable, the provisions relating to conversion or exchange of any debt securities of the series and the terms and conditions upon which such debt securities will be so convertible or exchangeable, including the conversion or exchange price, as applicable, or how it will be calculated and may be adjusted, any mandatory or optional (at our option or the holders’ option) conversion or exchange features, the applicable conversion or exchange period and the manner of settlement for any conversion or exchange;	
 
 	•	 	if other than the full principal amount thereof, the portion of the principal amount of debt securities of the series which shall be payable upon declaration of acceleration of the maturity thereof;	
 
 	•	 	additions to or changes in the covenants applicable to the particular debt securities being issued, including, among others, the consolidation, merger or sale covenant;	
 
 	•	 	additions to or changes in the events of default with respect to the securities and any change in the right of the trustee or the holders to declare the principal, premium, if any, and interest, if any, with respect to such securities to be due and payable;	
 
 	•	 	additions to or changes in or deletions of the provisions relating to covenant defeasance and legal defeasance;	
 
 	•	 	additions to or changes in the provisions relating to satisfaction and discharge of the indenture;	
 
 	•	 	additions to or changes in the provisions relating to the modification of the indenture both with and without the consent of holders of debt securities issued under the indenture;	
 
 	•	 	the currency of payment of debt securities if other than U.S. dollars and the manner of determining the equivalent amount in U.S. dollars;	
 
 	•	 	whether interest will be payable in cash or additional debt securities at our or the holders’ option and the terms and conditions upon which the election may be made;	
 
 	•	 	the terms and conditions, if any, upon which we will pay amounts in addition to the stated interest, premium, if any, and principal amounts of the debt securities of the series to any holder that is not a “United States person” for federal tax purposes;	
 
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 	•	 	any restrictions on transfer, sale or assignment of the debt securities of the series; and	
 
 	•	 	any other specific terms, preferences, rights or limitations of, or restrictions on, the debt securities, any other additions or changes in the provisions of the indenture, and any terms that may be required by us or advisable under applicable laws or regulations.	
Conversion or Exchange Rights
We will set forth in the applicable prospectus supplement the terms on which a series of debt securities may be convertible into or exchangeable for our common stock or our other securities. We will include provisions as to settlement upon conversion or exchange and whether conversion or exchange is mandatory, at the option of the holder or at our option. We may include provisions pursuant to which the number of shares of our common stock or our other securities that the holders of the series of debt securities receive would be subject to adjustment.
Consolidation, Merger or Sale
Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the indenture will not contain any covenant that restricts our ability to merge or consolidate, or sell, convey, transfer or otherwise dispose of our assets as an entirety or substantially as an entirety. However, any successor to or acquirer of such assets (other than a subsidiary of ours) must assume all of our obligations under the indenture or the debt securities, as appropriate.
Events of Default under the Indenture
Unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, the following are events of default under the indenture with respect to any series of debt securities that we may issue:
 
 	•	 	if we fail to pay any installment of interest on any series of debt securities, as and when the same shall become due and payable, and such default continues for a period of 90 days; provided, however, that a valid extension of an interest payment period by us in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of interest for this purpose;	
 
 	•	 	if we fail to pay the principal of, or premium, if any, on any series of debt securities as and when the same shall become due and payable whether at maturity, upon redemption, by declaration or otherwise, or in any payment required by any sinking or analogous fund established with respect to such series; provided, however, that a valid extension of the maturity of such debt securities in accordance with the terms of any indenture supplemental thereto shall not constitute a default in the payment of principal or premium, if any;	
 
 	•	 	if we fail to observe or perform any other covenant or agreement contained in the debt securities or the indenture, other than a covenant specifically relating to another series of debt securities, and our failure continues for 90 days after we receive written notice of such failure, requiring the same to be remedied and stating that such is a notice of default thereunder, from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of the applicable series; and	
 
 	•	 	if specified events of bankruptcy, insolvency or reorganization occur.	
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, by notice to us in writing, and to the trustee if notice is given by such holders, may declare the unpaid principal of, premium, if any, and accrued interest, if any, due and payable immediately. If an event of default specified in the last bullet point above occurs with respect to us, the principal amount of and accrued interest, if any, of each issue of debt securities then outstanding shall be due and payable without any notice or other action on the part of the trustee or any holder.
 
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The holders of a majority in principal amount of the outstanding debt securities of an affected series may waive any default or event of default with respect to the series and its consequences, except defaults or events of default regarding payment of principal, premium, if any, or interest, unless we have cured the default or event of default in accordance with the indenture. Any waiver shall cure the default or event of default.
Subject to the terms of the indenture, if an event of default under an indenture shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under such indenture at the request or direction of any of the holders of the applicable series of debt securities, unless such holders have offered the trustee reasonable indemnity. The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series, provided that:
 
 	•	 	the direction so given by the holder is not in conflict with any law or the applicable indenture; and	
 
 	•	 	subject to its duties under the Trust Indenture Act, the trustee need not take any action that might involve it in personal liability or might be unduly prejudicial to the holders not involved in the proceeding.	
A holder of the debt securities of any series will have the right to institute a proceeding under the indenture or to appoint a receiver or trustee, or to seek other remedies only if:
 
 	•	 	the holder has given written notice to the trustee of a continuing event of default with respect to that series;	
 
 	•	 	the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series have made written request;	
 
 	•	 	such holders have offered to the trustee indemnity satisfactory to it against the costs, expenses and liabilities to be incurred by the trustee in compliance with the request; and	
 
 	•	 	the trustee does not institute the proceeding, and does not receive from the holders of a majority in aggregate principal amount of the outstanding debt securities of that series other conflicting directions within 90 days after the notice, request and offer.	
These limitations do not apply to a suit instituted by a holder of debt securities if we default in the payment of the principal, premium, if any, or interest on, the debt securities.
We will periodically file statements with the trustee regarding our compliance with specified covenants in the indenture.
Modification of Indenture; Waiver
We and the trustee may change an indenture without the consent of any holders with respect to specific matters:
 
 	•	 	to cure any ambiguity, defect or inconsistency in the indenture or in the debt securities of any series;	
 
 	•	 	to comply with the provisions described above under “Description of Debt Securities–Consolidation, Merger or Sale;”	
 
 	•	 	to provide for uncertificated debt securities in addition to or in place of certificated debt securities;	
 
 	•	 	to add to our covenants, restrictions, conditions or provisions such new covenants, restrictions, conditions or provisions for the benefit of the holders of all or any series of debt securities, to make the occurrence, or the occurrence and the continuance, of a default in any such additional covenants, restrictions, conditions or provisions an event of default or to surrender any right or power conferred upon us in the indenture;	
 
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 	•	 	to add to, delete from or revise the conditions, limitations, and restrictions on the authorized amount, terms, or purposes of issue, authentication and delivery of debt securities, as set forth in the indenture;	
 
 	•	 	to make any change that does not adversely affect the interests of any holder of debt securities of any series in any material respect;	
 
 	•	 	to provide for the issuance of and establish the form and terms and conditions of the debt securities of any series as provided above under “Description of Debt Securities–General” to establish the form of any certifications required to be furnished pursuant to the terms of the indenture or any series of debt securities, or to add to the rights of the holders of any series of debt securities;	
 
 	•	 	to evidence and provide for the acceptance of appointment under any indenture by a successor trustee; or	
 
 	•	 	to comply with any requirements of the SEC in connection with the qualification of any indenture under the Trust Indenture Act.	
In addition, under the indenture, the rights of holders of a series of debt securities may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, unless we provide otherwise in the prospectus supplement applicable to a particular series of debt securities, we and the trustee may make the following changes only with the consent of each holder of any outstanding debt securities affected:
 
 	•	 	extending the fixed maturity of any debt securities of any series;	
 
 	•	 	reducing the principal amount, reducing the rate of or extending the time of payment of interest, or reducing any premium payable upon the redemption of any series of any debt securities; or	
 
 	•	 	reducing the percentage of debt securities, the holders of which are required to consent to any amendment, supplement, modification or waiver.	
Discharge
The indenture provides that we can elect to be discharged from our obligations with respect to one or more series of debt securities, except for specified obligations, including obligations to:
 
 	•	 	provide for payment;	
 
 	•	 	register the transfer or exchange of debt securities of the series;	
 
 	•	 	replace stolen, lost or mutilated debt securities of the series;	
 
 	•	 	pay principal of and premium and interest on any debt securities of the series;	
 
 	•	 	maintain paying agencies;	
 
 	•	 	hold monies for payment in trust;	
 
 	•	 	recover excess money held by the trustee;	
 
 	•	 	compensate and indemnify the trustee; and	
 
 	•	 	appoint any successor trustee.	
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, any premium, if any, 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 provide otherwise in the applicable prospectus supplement, in denominations of $1,000 and any integral multiple
 
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thereof. The indenture provides 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 DTC, or another depositary named by us and identified in the applicable prospectus supplement with respect to that series. To the extent the debt securities of a series are issued in global form and as book-entry, a description of terms relating to any book-entry securities will be set forth in the applicable prospectus supplement.
At the option of the holder, subject to the terms of the indenture 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 indenture 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 impose 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:
 
 	•	 	issue, register the transfer of, or exchange any debt securities of that series during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any debt securities that may be selected for redemption and ending at the close of business on the day of the mailing; or	
 
 	•	 	register the transfer of or exchange any debt securities so selected for redemption, in whole or in part, except the unredeemed portion of any debt securities we are redeeming in part.	
Information Concerning the Trustee
The trustee, other than during the occurrence and continuance of an event of default under an indenture, undertakes to perform only those duties as are specifically set forth in the applicable indenture. 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. Subject to this provision, the trustee is under no obligation to exercise any of the powers given it by the indenture 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.
Payment and Paying Agents
Unless we otherwise indicate in the applicable prospectus supplement, we will make payment of the interest on any debt securities on any interest payment date to the person in whose name the debt securities, or one or more predecessor securities, are registered at the close of business on the regular record date for the interest.
We will pay principal of and any premium and interest on the debt securities of a particular series at the office of the paying agents designated by us, except that unless we otherwise indicate in the applicable prospectus supplement, we will make interest payments by check that we will mail to the holder or by wire
 
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transfer to certain holders. Unless we otherwise indicate in the applicable prospectus supplement, we will designate the corporate trust office of the trustee as our sole paying agent for payments with respect to debt securities of each series. We will name in the applicable prospectus supplement any other paying agents that we initially designate for the debt securities of a particular series. We will maintain a paying agent in each place of payment for the debt securities of a particular series.
All money we pay to a paying agent or the trustee for the payment of the principal of or any premium or interest on any debt securities that remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the holder of the debt security thereafter may look only to us for payment thereof.
Governing Law
The indenture and the debt securities will be governed by and construed in accordance with the internal laws of the State of New York, except to the extent that the Trust Indenture Act of 1939 is applicable.
DESCRIPTION OF WARRANTS
The following description, together with the additional information we may include in any applicable prospectus supplements and free writing prospectuses, summarizes the material terms and provisions of the warrants that we may offer under this prospectus, which may consist of warrants to purchase common stock, preferred stock or debt securities and may be issued in one or more series. Warrants may be issued independently or together with common stock, preferred stock or debt securities offered by any prospectus supplement, and may be attached to or separate from those securities. While the terms we have summarized below will apply generally to any warrants that we may offer under this prospectus, we will describe the particular terms of any series of warrants that 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 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 its effectiveness.
We have filed forms of the warrant agreements as exhibits to the registration statement of which this prospectus is a part. We will file as exhibits to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of warrant agreement, if any, including a form of warrant certificate, that describes the terms of the particular series of warrants we are offering. The following summaries of material provisions of the warrants and the warrant agreements are subject to, and qualified in their entirety by reference to, all the provisions of the warrant agreement and warrant certificate applicable to the particular series of warrants that we may offer under this prospectus. We urge you to read the applicable prospectus supplements related to the particular series of warrants that we may offer under this prospectus, as well as any related free writing prospectuses, and the complete warrant agreements and warrant certificates that contain the terms of the warrants.
General
We will describe in the applicable prospectus supplement the terms relating to a series of warrants being offered, including:
 
 	•	 	the title of such securities;	
 
 	•	 	the offering price or prices and aggregate number of warrants offered;	
 
 	•	 	the currency or currencies for which the warrants may be purchased;	
 
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 	•	 	if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;	
 
 	•	 	if applicable, the date on and after which the warrants and the related securities will be separately transferable;	
 
 	•	 	if applicable, the minimum or maximum amount of such warrants which may be exercised at any one time;	
 
 	•	 	in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at which, and currency in which, this principal amount of debt securities may be purchased upon such exercise;	
 
 	•	 	in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which, and the currency in which, these shares may be purchased upon such exercise;	
 
 	•	 	the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreements and the warrants;	
 
 	•	 	the terms of any rights to redeem or call the warrants;	
 
 	•	 	the terms of any rights to force the exercise of the warrants;	
 
 	•	 	any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;	
 
 	•	 	the dates on which the right to exercise the warrants will commence and expire;	
 
 	•	 	the manner in which the warrant agreements and warrants may be modified;	
 
 	•	 	a discussion of any material or special U.S. federal income tax consequences of holding or exercising the warrants;	
 
 	•	 	the terms of the securities issuable upon exercise of the warrants; and	
 
 	•	 	any other specific terms, preferences, rights or limitations of or restrictions on the warrants.	
Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:
 
 	•	 	in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture; or	
 
 	•	 	in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.	
Exercise of Warrants
Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to the specified time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.
Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as
 
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provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent in connection with the exercise of the warrant.
Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.
Governing Law
Unless we provide otherwise in the applicable prospectus supplement, the warrants and warrant agreements, and any claim, controversy or dispute arising under or related to the warrants or warrant agreements, will be governed by and construed in accordance with the laws of the State of New York.
Enforceability of Rights by Holders of Warrants
Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants.
LEGAL OWNERSHIP OF SECURITIES
We 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 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 investors in securities issued in book-entry form or 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 securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.
Only the person in whose name a security is registered is recognized as the holder of that security. Global securities will be registered in the name of the depositary or its 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.
 
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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 financial 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
A global security may be terminated in certain situations as described under “-Special Situations When a Global Security Will Be Terminated,” 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 investor in street name would be registered in the name of 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 trustee or depositary will make all payments on those securities to them. These institutions pass along the payments they receive to their customers who are the beneficial owners, 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 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. We 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 choice because we are issuing the securities only in global form.
For example, once we make a payment or give a notice to the legal holder, we have no further responsibility for the payment or notice even if that legal 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 holders 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. Whether and how the legal holders contact the indirect holders is up to the 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 represented by one or more global securities or in street name, you should check with your own institution to find out:
 
 	•	 	how it handles securities payments and notices;	
 
 	•	 	whether it imposes fees or charges;	
 
 	•	 	how it would handle a request for the holders’ consent, if ever required;	
 
 	•	 	whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;	
 
 	•	 	how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and	
 
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 	•	 	if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.	
Global Securities
A global security is a security that represents one or any other number of individual securities held by a depositary. Generally, all securities represented by the same global securities will have the same terms.
Each 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 DTC will be 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 situations below under “-Special Situations When a Global Security Will Be Terminated.” As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and legal holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of 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 only as global securities, an investor should be aware of the following:
 
 	•	 	an investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;	
 
 	•	 	an investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;	
 
 	•	 	an investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;	
 
 	•	 	an investor may not be able to pledge his or her interest in the global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;	
 
 	•	 	the depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in the global security;	
 
 	•	 	we and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in the global security, nor will we or any applicable trustee supervise the depositary in any way;	
 
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 	•	 	the depositary may, and we understand that DTC will, require that those who purchase and sell interests in the global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and	
 
 	•	 	financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in the global security, may also have their own policies affecting payments, notices and other matters relating to the securities.	
There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.
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:
 
 	•	 	if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;	
 
 	•	 	if we notify any applicable trustee that we wish to terminate that global security; or	
 
 	•	 	if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.	
The applicable prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the prospectus supplement. When a global security terminates, the depositary, and neither we nor any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.
PLAN OF DISTRIBUTION
We may sell the securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell the securities to or through underwriters or dealers, through agents, or directly to one or more purchasers. We may distribute securities from time to time in one or more transactions:
 
 	•	 	at a fixed price or prices, which may be changed;	
 
 	•	 	at market prices prevailing at the time of sale;	
 
 	•	 	at prices related to such prevailing market prices; or	
 
 	•	 	at negotiated prices.	
We may also sell equity securities covered by this registration statement in an “at the market offering” as defined in Rule 415 under the Securities Act. Such offering may be made into an existing trading market for such securities in transactions at other than a fixed price, either:
 
 	•	 	on or through the facilities of the Nasdaq Global Select Market or any other securities exchange or quotation or trading service on which such securities may be listed, quoted or traded at the time of sale; and/or	
 
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 	•	 	to or through a market maker other than on the Nasdaq Global Select Market or such other securities exchanges or quotation or trading services.	
Such at-the-market offerings, if any, may be conducted by underwriters acting as principal or agent.
A prospectus supplement or supplements (and any related free writing prospectus that we may authorize to be provided to you) will describe the terms of the offering of the securities, including, to the extent applicable:
 
 	•	 	the name or names of any underwriters, dealers or agents, if any;	
 
 	•	 	the purchase price of the securities and the proceeds we will receive from the sale;	
 
 	•	 	any over-allotment options under which underwriters may purchase additional securities from us;	
 
 	•	 	any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;	
 
 	•	 	any public offering price;	
 
 	•	 	any discounts or concessions allowed or reallowed or paid to dealers; and	
 
 	•	 	any securities exchange or market on which the securities may be listed.	
Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.
If underwriters are used in the sale, they will acquire the securities for their own account and may resell the securities from time to time in one or more 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. We may offer the securities to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Subject to certain conditions, the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement. Any public offering price and any discounts or concessions allowed or reallowed or paid to dealers may change from time to time. We may use underwriters with whom we have a material relationship. We will describe in the prospectus supplement, naming the underwriter, the nature of any such relationship.
We may sell securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities, and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, our agent will act on a best-efforts basis for the period of its appointment.
We may authorize agents or underwriters to solicit offers by certain types of institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.
We may provide agents and underwriters with indemnification against civil liabilities related to this offering, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to these liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.
Other than common stock, all securities we offer will be new issues of securities with no established trading market. Any underwriters may make a market in these securities, but will not be obligated to do so and may discontinue any market making at any time without notice. We cannot guarantee the liquidity of the trading markets for any securities.
 
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Any underwriter may engage in overallotment, stabilizing transactions, short covering transactions and penalty bids. 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 stabilizing or 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 the activities at any time. These transactions may be effected on any exchange or over-the-counter market or otherwise.
Any underwriters who are qualified market makers on the Nasdaq Global Select Market may engage in passive market making transactions in the securities on the Nasdaq Global Select Market in accordance with Rule 103 of Regulation M, during the business day prior to the pricing of the offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded. Passive market making may stabilize the market price of the securities at a level above that which might otherwise prevail in the open market and, if commenced, may be discontinued at any time.
LEGAL MATTERS
Unless otherwise indicated in the applicable prospectus supplement, certain legal matters in connection with the offering and the validity of the securities offered by this prospectus, and any supplement thereto, has been passed upon by Cooley LLP.
EXPERTS
Ernst & Young LLP, independent registered public accounting firm, has audited our financial statements included in our Annual Report on Form 10-K for the year ended December 31, 2017, 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.
WHERE YOU CAN FIND MORE INFORMATION
This prospectus is part of a registration statement we filed with the SEC. This prospectus does not contain all of the information set forth in the registration statement and the exhibits to the registration statement. For further information with respect to us and the securities we are offering under this prospectus, we refer you to the registration statement and the exhibits and schedules filed as a part of the registration statement. Neither we nor any agent, underwriter or dealer has authorized any person to provide you with different information. We are not making an offer of these securities in any state where the offer is not permitted. You should not assume that the information in this prospectus is accurate as of any date other than the date on the front page of this prospectus, regardless of the time of delivery of this prospectus or any sale of the securities offered by this prospectus.
We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy the registration statement, as well as any other document filed by us with the SEC, at the SEC’s Public Reference Room at 100 F Street NE, Washington, D.C. 20549. You can also request copies of
 
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these documents by writing to the SEC and paying a fee for the copying cost. You may obtain information on the operation of the Public Reference Room by calling the SEC at (800) SEC-0330. The SEC maintains a website that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC, including Tocagen. The address of the SEC website is www.sec.gov.
We maintain a website at www.tocagen.com. Information contained in or accessible through our website does not constitute a part of this prospectus.
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE
The SEC allows us to “incorporate by reference” information into this prospectus, which means that we can disclose important information to you by referring you to another document filed separately with the SEC. The SEC file number for the documents incorporated by reference in this prospectus is 001-38052. The documents incorporated by reference into this prospectus contain important information that you should read about us.
The following documents are incorporated by reference into this document:
 
 	•	 	our Annual Report on Form 10-K for the fiscal year ended December 31, 2017, filed with the SEC on March 9, 2018;	
 
 	•	 	our Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2018, filed with the SEC on May 11, 2018;	
 
 	•	 	the information specifically incorporated by reference into our Annual Report on Form 10-K for the fiscal year ended December  31, 2017 from our definitive proxy statement on Schedule 14A (other than information furnished, rather than filed) filed with the SEC on April 30, 2018;	
 
 	•	 	our Current Reports on Form 8-K (other than information furnished, rather than filed) filed with the SEC on January  12, 2018, February 13, 2018, April 19, 2018 and May 23, 2018; and	
 
 	•	 	the description of our common stock, which is registered under Section 12 of the Exchange Act, in our registration statement on Form 8-A, filed with the SEC on April 4, 2017, including all amendments or reports filed for the purpose of updating such description.	
We also incorporate by reference into this prospectus all documents (other than Current Reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed on such form that are related to such items) that are filed by us with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus but prior to the termination of the offering. These documents include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as proxy statements.
We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with the prospectus, including exhibits which are specifically incorporated by reference into such documents. You should direct any requests for documents by writing us at 3030 Bunker Hill Street, Suite 230, San Diego, California 92109, Attn: Corporate Secretary or telephoning us at (858) 412-8400.
Any statement contained herein or in a document incorporated or deemed to be incorporated by reference into this document will be deemed to be modified or superseded for purposes of the document to the extent that a statement contained in this document or any other subsequently filed document that is deemed to be incorporated by reference into this document modifies or supersedes the statement.
 
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DISCLOSURE OF COMMISSION’S POSITION ON INDEMNIFICATION FOR
SECURITIES ACT LIABILITY
Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or persons controlling the Company pursuant to the DGCL, we have been informed that in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.
 
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