As filed withFiled With the Securities and Exchange Commission on March 26, 2014January 25, 2016

Registration No. 333-            333-208760

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

AMENDMENT NO. 1

TO

FORMS-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

SPECTRUM PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

11500 South Eastern Avenue, Suite 240

Henderson, Nevada 89052

(702) 835-6300

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

Rajesh C. Shrotriya, M.D.

Chief Executive Officer and President

11500 South Eastern Avenue, Suite 240

Henderson, Nevada 89052

(702) 835-6300

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

Copies to:

Shivbir S. Grewal, Esq.

Marc G. Alcser, Esq.

Stradling Yocca Carlson & Rauth

660 Newport Center Drive, Suite 1600

Newport Beach, California 92660

(949) 725-4000

Approximate date of commencement of proposed sale to the public:From time to time after the effective date of this Registration Statement becomes effective.

Statement.

If the only securities being registered on this Formform are being offered pursuant to dividend or interest reinvestment plans, please check the following box.   ¨

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1993,1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.   x

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

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

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

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

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer,”filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

CALCULATION OF REGISTRATION FEE

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

EXPLANATORY NOTE

This registration statement contains two prospectuses:

The base prospectus immediately follows this explanatory note. The specific terms of any securities to be offered pursuant to the base prospectus will be specified in a prospectus supplement to the base prospectus. The sales agreement prospectus immediately follows the base prospectus. The common stock that may be offered, issued and sold by the Registrant under the sales agreement prospectus is included in the $250,000,000 of securities that may be offered, issued and sold by the Registrant under the base prospectus.

The information in this prospectus is not complete and may be changed. The selling stockholderWe may not sell thethese securities or accept an offer to buy these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting an offeroffers to buy these securities in any jurisdictionstate where thesuch offer or sale is not permitted.

Subject to Completion, Dated March 26, 2014SUBJECT TO COMPLETION, DATED JANUARY 25, 2016

PROSPECTUS$250,000,000

Debt Securities

Preferred Stock

1,000,000 Shares of Common Stock

Warrants

Units

This prospectus relates to the sale or other disposition of up to 1,000,000 shares of our common stock, $0.001 par value, by the selling stockholder named in this prospectus. The selling stockholder acquired the commonpreferred stock, from us in a private placement transaction pursuant to the terms of a Licensedebt securities, warrants for debt or equity securities and Collaboration Agreement dated as of February 2, 2010, as amended October 3, 2013, by and between the selling stockholder and us. We are registering the shares as required by a Registration Rights and Stockholder Agreement dated as of February 2, 2010, which we entered into with the selling stockholder. However, the registrationunits consisting of the shares does not necessarily meanforegoing that any of such shares will be offered or sold by the selling stockholder. We are not selling any common stock under this prospectus and will not receive any of the proceeds from the sale of shares of our common stock by the selling stockholder.

The selling stockholder or its pledgees, donees, transferees or other successors-in-interestwe may sell from time to time sellin one or otherwise disposemore transactions. The aggregate initial offering price of any or all of their shares of common stock described insecurities sold under this prospectus in a numberwill not exceed $250,000,000. We will provide the specific terms and conditions of different waysthese transactions and at varying prices. We provide more information about how the selling stockholdersecurities we may sell its shares of common stock in the section entitled “Plan of Distribution” onpages 6-8 ofsupplements to this prospectus. We have agreed to bear all costs, expenses and feesprospectus prepared in connection with the registration of the common stock offered by the selling stockholder. However, weeach transaction. The applicable prospectus supplement will not be payingcontain information, where applicable, as to other listings, if any, underwriting discounts, commissions or brokerage fees in this offering or any fees or expenses of the selling stockholder’s legal counsel.

Our common stock is listed on the Nasdaq Global Select Market, or the NASDAQ, or any securities exchange of the securities covered by the prospectus supplement. Any such prospectus supplement may also add, update or change information in this prospectus. We may also authorize one or more free writing prospectuses to be provided to you in connection with these offerings. You should read this prospectus, any applicable prospectus supplement and any related free writing prospectuses, as well as the documents incorporated by reference or deemed to be incorporated by reference into this prospectus, carefully before you invest. This prospectus may not be used to offer or sell securities unless accompanied by a prospectus supplement.

Our common stock is traded on the NASDAQ under the symbol “SPPI.” On March 25, 2014, the last reported sale price for our common stock was $7.72 per share.

The selling stockholder and any broker-dealer executing sell orders on behalf of the selling stockholder, may be deemed to be “underwriters” within the meaning of the Securities Act of 1933, as amended, or the Securities Act. Commissions received by any broker-dealer may be deemed to be underwriting commissions under the Securities Act. See “Plan of Distribution.”

Investing in our common stocksecurities involves a high degree of risk. See “Risk Factors” beginning on page 4 of this prospectus and as updatedcontained in our future filings made with the Securities and Exchange Commission that are incorporatedand the applicable prospectus supplement.

The securities may be sold directly by reference intous to investors, through agents designated from time to time or to or through underwriters or dealers. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution” in this prospectus. If any underwriters are involved in the sale of these securities with respect to which this prospectus is being delivered, the names of such underwriters and any applicable commissions or discounts and over-allotment options will be set forth in a prospectus supplement. The price to the public of such securities and the net proceeds that we expect to receive from such sale will also be set forth in a prospectus supplement. No securities may be sold without delivery of this prospectus and the applicable prospectus supplement describing the method and terms of the offering of such securities.

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

The date of this prospectus is                      , 20142016.

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that we have filed with the U.S. Securities and Exchange Commission, or the Commission. It is importantSEC, utilizing a “shelf” registration process. Under this shelf registration process, we may, from time to time, sell common stock, preferred stock, debt securities, warrants for debt and equity securities and units consisting of the foregoing in one or more transactions. The aggregate public offering price of the securities we sell in these transactions will not exceed $250,000,000. This prospectus only provides you with a general description of the securities we may sell in these transactions. Each time we sell any securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement also may add, update or change information contained in this prospectus. We may also authorize one or more free writing prospectuses to read and considerbe provided to you that may contain material information relating to these offerings.

This prospectus does not contain all of the information containedincluded in the registration statement we filed with the SEC. For further information about us or incorporated by reference intothe securities offered hereby, you should carefully read this prospectus, and any applicable prospectus supplement, before making any decision whether to invest in our common stock. This prospectus incorporatesrelated free writing prospectuses, the information and documents incorporated herein by reference important business and financial information about us that is not included in or delivered with this document. You should also read and consider the additional information contained inunder the documents that we have incorporated into this prospectus by reference, as described in “Incorporation of Certain Information by Reference” andheading “Where You Can Find MoreAdditional Information” in this prospectus.before making an investment decision.

You should rely only on the information contained in or incorporated by reference intoin this prospectus, or any applicable prospectus supplement.supplement and any related free writing prospectuses that we may authorize to be provided to you. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and the accompanying supplement to givethis prospectus are not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdiction where the offer or provide any information different fromsale is not permitted. You should assume that the information that is containedappearing in this prospectus, any applicable prospectus supplement or any related free writing prospectuses, as well as information we have previously filed with the SEC and incorporated by reference, into this prospectus or any accompanying prospectus supplement and, if given, such information must not be relied upon as having been made or authorized by us. The information contained in this prospectus is accurate only as of the date on the frontcover of this prospectus and information appearing in any applicable prospectus supplement is accurate only as of the date of the applicable prospectus supplement. Additionally, any information we have incorporated by reference in this prospectus or any applicable prospectus supplement is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus, any applicable prospectus supplement or any sale of our common stock.those documents. Our business, financial condition, results of operations and prospectusprospects may have changed since that date.those dates.

This prospectus may not be used to consummate sales of any of these securities unless it is accompanied by a prospectus supplement. To the extent there are inconsistencies between any prospectus supplement, this prospectus and/or any accompanying prospectus supplement does not constitute an offer or solicitationdocuments incorporated by anyone in any state in which such offer or solicitation is not authorized or in whichreference, the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make such offer or solicitation.document with the most recent date will control.

RISK FACTORS

An investment in our securities involves a high degree of risk. Prior to making a decision about investing in our securities, you should carefully consider the risks, uncertainties and assumptions discussed under Item 1A, “Risk Factors,” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2013 and any updates described in our subsequent Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, all of which are incorporated herein by reference and may be amended, supplemented or superseded from time to time by other reports we file with the Commission in the future, together with information in this prospectus and any other information incorporated by reference into this prospectus. See the section of this prospectus entitled “Where You Can Find More Information”. The risks and uncertainties we have described are not the only ones we face. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our operations. The occurrence of any of these known or unknown risks might cause you to lose all or part of your investment in the offered securities.

FORWARD-LOOKING STATEMENTS

This prospectus and the information and documents incorporated by reference into this prospectus contain certain statements that constitute “forward-looking statements” within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, andin reliance upon the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include, but are not limited to,without limitation, statements regarding the success, safety and efficacy of our drug products, product approvals, product sales, revenues, development timelines, product acquisitions, liquidity and capital resources and trends. Suchtrends, and other statements may be signified by termscontaining forward-looking words, such as, “anticipates,“believes,” “believes,“may,” “could,” “seeks,“would,” “estimates,“will,” “expects,” “intends,” “may,“estimates,” “anticipates,” “plans,” “potential,“seeks,” “predicts,” “projects,” “should,” “will,” “would”or “continues” or the negative thereof or variation thereon or similar expressions and the negatives of those terms. Thoseterminology (although not all forward-looking statements appear in this prospectus and the documents incorporated herein by reference and includecontain these words). Such forward-looking statements regarding the intent, belief or current expectations of the company and management that are subject to known and unknown risks, uncertainties and assumptions and other factors that could cause actual results and the timing of certain events to differ materially from future results expressed or implied by such forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the section of this prospectus entitled “Risk Factors” set forth above.

This prospectus and the information and documents incorporated by reference in this prospectus also contain statements that are based on management’s current expectationsthe beliefs of our management as well as assumptions made by and beliefs, including estimates and projections aboutinformation currently available to our company, industry, financial condition, results of operations and other matters. These statements aremanagement. Readers should not guarantees of future performance and are subject to numerous risks, uncertainties, and assumptions that are difficult to predict.

Becauseput undue reliance on these forward-looking statements. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified, you should not rely upon forward-looking statements as predictions of future events. The events and circumstances reflected in the forward-looking statements may not be achieved or occur andquantified; therefore, our actual results couldmay differ materially from those projecteddescribed in theany forward-looking statements. Except as required byThe risks and uncertainties include those noted in our SEC filings or any applicable law, includingprospectus supplement.

We urge you to consider these factors carefully in evaluating the securities laws of the United States and the rules and regulations of the Commission, we do not plan to publicly update or revise any forward-looking statements contained herein after we distributein this prospectus and any prospectus supplement. All subsequent written or oral forward-looking statements attributable to our company or persons acting on our behalf are expressly qualified in their entirety by these cautionary statements. The forward-looking statements included in this prospectus are made only as of the date of this prospectus. We undertake no obligation to update publicly any forward-looking statements, whether as a result of any new information, future events or otherwise.otherwise, except to the extent that we are required to do so by law.

USE OF PROCEEDS

Unless we indicate otherwise in the applicable prospectus supplement, we anticipate that the net proceeds from the sale of the securities offered from time to time hereby will be used for general corporate purposes, including, without limitation, sales and marketing activities, clinical development, making acquisitions of assets, businesses, companies or securities, capital expenditures and for working capital. When a particular series of securities is offered, the related prospectus supplement will set forth our intended use of the net proceeds we receive from the sale of the securities. Pending the application of the net proceeds, we may invest the proceeds in short-term, interest-bearing instruments or other investment-grade securities.

RATIO OF EARNINGS TO FIXED CHARGES

The following table sets forth our ratio of earnings to fixed charges for the periods indicated:

The ratios of earnings to fixed charges were computed by dividing earnings by fixed charges. For this purpose, earnings include pre-tax loss before fixed charges included in the determination of pre-tax loss. Fixed charges consist of interest costs, whether expensed or capitalized, the amortization of debt discount and issuance costs, and the interest factor of operating rental expense.

RATIO OF EARNINGS TO COMBINED FIXED CHARGES AND PREFERREDSTOCK DIVIDENDS

The following table sets forth our ratio of earnings to combined fixed charges and preferred stock dividends for the periods indicated:

DESCRIPTION OF CAPITAL STOCK WE MAY OFFER

General

Our authorized capital stock consists of 175,000,000 shares of common stock, par value $0.001 per share, and 5,000,000 shares of preferred stock, par value $0.001 per share.

The following description of our common stock and preferred stock, together with the additional information included in any applicable prospectus supplements or related free writing prospectuses, summarizes the material terms and provisions of these types of securities, but it is not complete. For the complete terms of our common stock and preferred stock, please refer to our amended certificate of incorporation and our amended and restated bylaws that are incorporated by reference into the registration statement which includes this prospectus and, with respect to preferred stock, any certificate of designation that we may file with the SEC for a series of preferred stock we may designate, if any.

We will describe in a prospectus supplement or related free writing prospectuses, the specific terms of any common stock or preferred stock we may offer pursuant to this prospectus. If indicated in a prospectus supplement, the terms of such common stock or preferred stock may differ from the terms described below.

Common Stock

As of January 15, 2016, there were 68,172,919 shares of common stock outstanding. The holders of our common stock are registeringentitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. The holders of common stock are not entitled to cumulative voting rights with respect to the election of directors, and as a consequence, minority stockholders will not be able to elect directors on the basis of their votes alone.

Subject to preferences that may be applicable to any then outstanding shares of preferred stock, holders of common stock are entitled to receive ratably such dividends as may be declared by the board of directors out of funds legally available therefor. In the event of a liquidation, dissolution or winding up of us, holders of the common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any then outstanding shares of preferred stock. Holders of common stock have no preemptive rights and no right to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to our common stock. All outstanding shares of common stock are, and all shares of common stock to be issued under this prospectus will be, fully paid and non-assessable. The rights, preferences and privileges of holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any of our outstanding preferred stock.

Listing

Our common stock is listed under the symbol “SPPI” on the NASDAQ.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Dividends

We have not declared any cash dividends on our common stock since 2012 and we do not anticipate paying any cash dividends on our common stock in the foreseeable future.

Stockholder Rights Plan

On December 13, 2010, we adopted a Stockholder Rights Plan pursuant to which we have distributed rights to purchase units of our Series B Junior Participating Preferred Stock. The rights become exercisable upon the earlier of ten days after a person or group of affiliated or associated persons has acquired 15% or more of the outstanding shares of our common stock covered by this prospectusor ten business days after a tender offer has commenced that would result in a person or group beneficially owning 15% or more of our outstanding common stock, other than pursuant to registrationa transaction approved in advance by our Board of Directors. The description and terms of the rights grantedare set forth in a Rights Agreement between us and ComputerShare Trust Company, N.A., as rights agent.

Preferred Stock

We are authorized to issue a total of 5,000,000 shares of preferred stock. Of the 5,000,000 authorized shares of preferred stock, we are authorized to issue 1,500,000 shares of Series B Junior Participating Preferred Stock and 2,000 shares of Series E Convertible Voting Preferred Stock. As of January 15, 2016, 20 shares of Series E Convertible Voting Preferred Stock were issued and outstanding. These shares are convertible into 40,000 shares of common stock. There are no dividends payable on the Series E Convertible Voting Preferred Stock.

Each share of Series E Convertible Voting Preferred Stock has a liquidation preference equal to 120% of the stated value of $10,000 plus any declared and unpaid dividends on such share, subject to adjustment in certain circumstances.

Holders of our Series E Convertible Voting Preferred Stock have full voting rights and powers equal to the selling stockholder. The selling stockholder will receive allvoting rights and powers of holders of common stock, and are entitled to the proceeds fromnumber of votes equal to the sale or other dispositionnumber of shares of common stock into which their shares of Series E Convertible Voting Preferred Stock can be converted. Pursuant to the Certificate of Designation for the Series E Convertible Voting Preferred Stock, the number of shares of our common stock coveredthat may be acquired by this prospectus. We are not selling any securities under this prospectus and will not receiveholder of Series E Convertible Voting Preferred Stock upon any proceeds from the sale or other dispositionconversion of the preferred stock, or that shall be entitled to voting rights, is limited to the extent necessary to ensure that following such conversion, the number of shares of our common stock coveredthen beneficially owned by this prospectus.

SELLING STOCKHOLDERS

We have prepared this prospectus to allowsuch holder and any other person or entities whose beneficial ownership of common stock would be aggregated with the selling stockholder or its transferees, pledgees, assignees, distributees, donees or other successors in interest to sell or otherwise disposeholder’s for purposes of from time to time, up to an aggregatethe Exchange Act does not exceed 4.95% of 1,000,000the total number of shares of our common stock then outstanding.

Preferred stock may be issued from time to time, in one or more series, as authorized by the board of directors. The prospectus supplement relating to the sellingpreferred shares offered thereby will include specific terms of any preferred shares offered, including, if applicable:

The transfer agent and registrar for any series or class of preferred stock will be set forth in the applicable prospectus supplement.

Anti-Takeover Provisions

Our amended certificate of incorporation and amended and restated bylaws contain provisions that, together with the ownership position of the officers, directors and their affiliates, could discourage potential takeover attempts and make it more difficult for stockholders to change management, which could adversely affect the market price of our common stock.

Our amended certificate of incorporation limits the extent to which our directors are personally liable to us and our stockholders, to the fullest extent permitted by the Delaware General Corporation Law, or DGCL. The inclusion of this provision in our amended certificate of incorporation may reduce the likelihood of derivative litigation against directors and may discourage or deter stockholders or management from bringing a lawsuit against directors for breach of their duty of care.

Our amended and restated bylaws provide that special meetings of stockholders can be called only by the board of directors, the chairman of the board of directors or the chief executive officer. Stockholders are not permitted to call a special meeting and cannot require the board of directors to call a special meeting. There is no right of stockholders to act by written consent without a meeting, unless the consent is unanimous. Any vacancy on the board of directors resulting from death, resignation, removal or otherwise or newly created directorships may be filled only by vote of the majority of directors then in office, or by a sole remaining director. Our amended and restated bylaws establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, except for nominations made by or at the direction of the board of directors or a committee of the board.

In addition to our rights plan, our amended certificate of incorporation and our amended and restated bylaws, certain provisions of Delaware law may make the acquisition of the company by tender offer, a proxy contest or otherwise, or the removal of our officers and directors, more difficult. For example, we are subject to the “business combination” statute of the DGCL. Section 203 of the DGCL prohibits certain publicly-held Delaware corporations from engaging in a business combination with an interested stockholder for a period of three years following the time such person became an interested stockholder unless the business combination is approved in a specified manner. Generally, an interested stockholder is a person who, together with its affiliates and associates, owns 15% or more of the corporation’s voting stock, or is affiliated with the corporation and owns or owned 15% of the corporation’s voting stock within three years before the business combination.

DESCRIPTION OF DEBT SECURITIES WE MAY OFFER

This prospectus describes the general terms and provisions of our debt securities. When we offer to sell a particular series of debt securities, we will provide the specific terms of the series in a prospectus supplement or any related free writing prospectuses relating to the series, including any pricing supplement, and such terms may differ from those described below. Accordingly, for a description of the terms of any series of debt securities, you must refer to the prospectus supplement and any free writing prospectuses relating to that series and the description of the debt securities in this prospectus. To the extent the information contained in the prospectus supplement differs from this summary description, you should rely on the information in the prospectus supplement.

The debt securities offered by this prospectus will be issued under an indenture between us and the trustee, for one or more series of debt securities designated in the applicable prospectus supplement. The indenture is subject to, and governed by, the Trust Indenture Act of 1939, as amended. We incorporate by reference the form of indenture as an exhibit to the registration statement of which this prospectus forms a part and you should read the indenture carefully for the provisions that may be important to you. We have summarized selected portions of the indenture below. The summary is not complete. Terms used in the summary and not defined in this prospectus have the meanings specified in the indenture. The indenture which is filed as an exhibit to the registration statement of which this prospectus is a part may not have the same terms as an indenture entered into in connection with the issuance of the debt securities and therefore you should refer to the prospectus supplement for the description of any issued debt securities as well as the indenture governing such securities which will be filed with the SEC at such time as the debt securities are issued.

General

We may offer under this prospectus up to $250,000,000 in aggregate principal amount of secured or unsecured debt securities, or if debt securities are issued at a discount, or in a foreign currency or composite currency, such principal amount as may be sold for an initial public offering price of up to $250,000,000. The debt securities may be either senior debt securities, senior subordinated debt securities or subordinated debt securities.

We can issue an unlimited amount of debt securities under the indenture that may be in one or more series with the same or various maturities, at par, at a premium or at a discount. The terms of each series of debt securities will be established by or pursuant to a resolution of our board of directors and detailed or determined in the Licensemanner provided in a board of directors’ resolution, an officers’ certificate or by a supplemental indenture.

We will set forth in a prospectus supplement (including any pricing supplement) and Collaboration Agreement. See “Prospectus Summary—Licenseany free writing prospectuses relating to any series of debt securities being offered, the initial offering price, the aggregate principal amount and Collaboration Agreementthe following terms of the debt securities, as applicable:

We may issue debt securities that are exchangeable and/or convertible into shares of our common stock or preferred stock. The table below presents information regardingterms, if any, on which the selling stockholder,debt securities may be exchanged for and/or converted will be set forth in the applicable prospectus supplement and any related free writing prospectuses. Such terms may include provisions for conversion, either mandatory, at the option of the holder or at our option, in which case the number of shares of common stock or other securities to be received by the holders of debt securities would be calculated as of a time and in the manner stated in the prospectus supplement and any related free writing prospectuses.

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

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

Transfer and Exchange

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

Certificated Debt Securities. You may transfer or exchange certificated debt securities at the trustee’s office or paying agencies in accordance with the terms of the indenture. No service charge will be made for any transfer or exchange of certificated debt securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with a transfer or exchange.

You may transfer certificated debt securities and the right to receive the principal of, premium and interest on, certificated debt securities only by surrendering the old certificate representing those certificated debt securities and either we or the trustee will reissue the old certificate to the new holder or we or the trustee will issue a new certificate to the new holder.

Global Debt Securities and Book-Entry System. Each global debt security representing book-entry debt securities will be deposited with, or on behalf of, the depositary, and registered in the name of the depositary or a nominee of the depositary.

We will require the depositary to agree to follow the following procedures with respect to book-entry debt securities.

Ownership of beneficial interests in book-entry debt securities will be limited to persons that have accounts with the depositary for the related global debt security, whom we refer to as participants, or persons that may hold interests through participants. Upon the issuance of a global debt security, the depositary will credit, on its book-entry registration and transfer system, the participants’ accounts with the respective principal amounts of the book-entry debt securities represented by the global debt security beneficially owned by such participants. The accounts to be credited will be designated by any dealers, underwriters or agents participating in the distribution of the book-entry debt securities. Ownership of book-entry debt securities will be shown on, and the transfer of the ownership interests will be effected only through, records maintained by the depositary for the related global debt security (with respect to interests of participants) and on the records of participants (with respect to interests of persons holding through participants). The laws of some states may require that certain purchasers of securities take physical delivery of such securities in definitive form. These laws may impair the ability to own, transfer or pledge beneficial interests in book-entry debt securities.

So long as the depositary for a global debt security, or its nominee, is the registered owner of that global debt security, the depositary or its nominee, as the case may be, will be considered the sole owner or holder of the book-entry debt securities represented by such global debt security for all purposes under the indenture. Except as described herein, beneficial owners of book-entry debt securities will not be entitled to have securities registered in their names, will not receive or be entitled to receive physical delivery of a certificate in definitive form representing securities and will not be considered the owners or holders of those securities under the indenture. Accordingly, to exercise any rights of a holder under the indenture, each person beneficially owning book-entry debt securities must rely on the procedures of the depositary for the related global debt security and, if that person is not a participant, on the procedures of the participant through which that person owns its interest.

We will make payments of principal of, and premium and interest on, book-entry debt securities to the depositary or its nominee, as the case may be, as the registered holder of the related global debt security. We, the trustee and any other agent of ours or agent of the trustee will not have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in a global debt security or for maintaining, supervising or reviewing any records relating to such beneficial ownership interests.

We expect that the depositary, upon receipt of any payment of principal of, premium or interest on, a global debt security, will immediately credit participants’ accounts with payments in amounts proportionate to the respective amounts of book-entry debt securities held by each participant as shown on the records of the depositary. We also expect that payments by participants to owners of beneficial interests in book-entry debt securities held through those participants will be governed by standing customer instructions and customary practices, as is now the case with the securities held for the accounts of customers in bearer form or registered in “street name,” and will be the responsibility of those participants.

We will issue certificated debt securities in exchange for each global debt security if the depositary is at any time unwilling or unable to continue as depositary or ceases to be a clearing agency registered under the Exchange Act, and a successor depositary registered as a clearing agency under the Exchange Act is not appointed by us within 90 days. In addition, we may at any time and in our sole discretion determine not to have any of the book-entry debt securities of any series represented by one or more global debt securities and, in that event, we will issue certificated debt securities in exchange for the global debt securities of that series. Global debt securities will also be exchangeable by the holders for certificated debt securities if an event of default with respect to the book-entry debt securities represented by those global debt securities has occurred and is continuing. Any certificated debt securities issued in exchange for a global debt security will be registered in such name or names as the depositary shall instruct the trustee. We expect that such instructions will be based upon directions received by the depositary from participants with respect to ownership of book-entry debt securities relating to such global debt security.

We have obtained the foregoing information in this section concerning the depositary and the depositary’s book-entry system from sources we believe to be reliable. We take no responsibility for the depositary’s performance of its obligations under the rules and regulations governing its operations.

No Protection in the Event of a Change in Control

Unless we provide otherwise in the applicable prospectus supplement or any related free writing prospectuses, the debt securities will not contain any provisions which may afford holders of the debt securities protection in the event we have a change in control or in the event of a highly leveraged transaction (whether or not such transaction results in a change in control) that could adversely affect holders of debt securities.

Covenants

We will describe in the applicable prospectus supplement and any related free writing prospectuses any restrictive covenants applicable to an issue of debt securities.

Consolidation, Merger and Sale of Assets

We may not consolidate with or merge into, or convey, transfer or lease all or substantially all of our properties and assets to, any person, such person to be referred to as a “successor person”, and we may not permit any person to merge into, or convey, transfer or lease its properties and assets substantially as an entirety to us, unless:

Events of Default

“Event of default” means, with respect to any series of debt securities, any of the following:

No event of default with respect to a particular series of debt securities (except as to certain events of bankruptcy, insolvency or reorganization) necessarily constitutes an event of default with respect to any other series of debt securities. An event of default may sellalso be an event of default under our bank credit agreements or otherwise dispose ofother debt securities in existence from time to time and under certain guaranties by us of any subsidiary indebtedness. In addition, certain events of default or an acceleration under the indenture may also be an event of default under some of our other indebtedness outstanding from time to time.

If an event of default with respect to debt securities of any series at the time outstanding occurs and is continuing (other than certain events of our bankruptcy, insolvency or reorganization), then the trustee or the holders of not less than a majority in principal amount of the outstanding debt securities of that series may, by written notice to us (and to the trustee if given by the holders), declare to be due and payable immediately the principal (or, if the debt securities of that series are discount securities, that portion of the principal amount as may be specified in the terms of that series) of and accrued and unpaid interest, if any, of all debt securities of that series. In the case of an event of default resulting from certain events of bankruptcy, insolvency or reorganization, the principal (or such specified amount) of and accrued and unpaid interest, if any, of all outstanding debt securities will become and be immediately due and payable without any declaration or other act by the trustee or any holder of outstanding debt securities. At any time after a declaration of acceleration with respect to debt securities of any series has been made, but before the trustee has obtained a judgment or decree for payment of the money due, the holders of a majority in principal amount of the outstanding debt securities of that series may, subject to our having paid or deposited with the trustee a sum sufficient to pay overdue interest and principal which has become due other than by acceleration and certain other conditions, rescind and annul such acceleration if all events of default, other than the non-payment of accelerated principal and interest, if any, with respect to debt securities of that series, have been cured or waived as provided in the indenture. For information as to waiver of defaults see the discussion under “Modification and Waiver” below. We refer you to the applicable prospectus supplement and any free writing prospectuses relating to any series of debt securities that are discount securities for the particular provisions relating to acceleration of a portion of the principal amount of the discount securities upon the occurrence of an event of default and the continuation of an event of default.

The indenture provides that the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request of any holder of outstanding debt securities, unless the trustee receives indemnity satisfactory to it against any loss, liability or expense. Subject to certain rights of the trustee, the holders of a majority in principal amount of the outstanding debt securities of any series shall 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.

No holder of any debt security of any series will have any right to institute any proceeding, judicial or otherwise, with respect to the indenture or for the appointment of a receiver or trustee, or for any remedy under the indenture, unless:

Notwithstanding the foregoing, the holder of any debt security will have an absolute and unconditional right to receive payment of the principal of, premium and any interest on that debt security on or after the due dates expressed in that debt security and to institute suit for the enforcement of payment.

The indenture requires us, within 90 days after the end of our fiscal year, to furnish to the trustee a certificate as to compliance with the indenture. The indenture provides that the trustee may withhold notice to the holders of debt securities of any series of any default or event of default (except in payment on any debt securities of that series) with respect to debt securities of that series if it in good faith determines that withholding notice is in the interest of the holders of those debt securities.

Modification and Waiver

We and the trustee may modify and amend the indenture with the consent of the holders of at least a majority in principal amount of the outstanding debt securities of each series affected by the modifications or amendments. We and the trustee may not make any modification or amendment without the consent of the holder of each affected debt security then outstanding if that amendment will:

Except for certain specified provisions, the holders of at least a majority in principal amount of the outstanding debt securities of any series may, on behalf of the holders of all debt securities of that series, waive our compliance with provisions of the indenture. The holders of a majority in principal amount of the outstanding debt securities of any series may, on behalf of the holders of all the debt securities of that series, waive any past default under the indenture with respect to that series and its

consequences, except a default in the payment of the principal of, premium or any interest on any debt security of that series; provided, however, that the holders of a majority in principal amount of the outstanding debt securities of any series may rescind an acceleration and its consequences, including any related payment default that resulted from the acceleration.

Defeasance of Debt Securities and Certain Covenants in Certain Circumstances

Legal Defeasance. The indenture provides that, unless the terms of the applicable series of debt securities provide otherwise, we may be discharged from any and all obligations in respect of the debt securities of any series (except for certain obligations to register the transfer or exchange of debt securities of the series, to replace stolen, lost or mutilated debt securities of the series, and to maintain paying agencies and certain provisions relating to the treatment of funds held by paying agents). We will be so discharged upon the deposit with the trustee, in trust, of money and/or U.S. government obligations or, in the case of debt securities denominated in a single currency other than U.S. dollars, foreign government obligations (as described at the end of this section), that, through the payment of interest and principal in accordance with their terms, will provide money in an amount sufficient in the opinion of a nationally recognized firm of independent public accountants to pay and discharge each installment of principal, premium and interest on and any mandatory sinking fund payments in respect of the debt securities of that series on the stated maturity of such payments in accordance with the terms of the indenture and those debt securities.

This discharge may occur only if, among other things, we have delivered to the trustee an officers’ certificate and an opinion of counsel stating that we have received from, or there has been published by, the U.S. Internal Revenue Service a ruling or, since the date of execution of the indenture, there has been a change in the applicable U.S. federal income tax law, in either case to the effect that holders of the debt securities of such series will not recognize income, gain or loss for U.S. federal income tax purposes as a result of the deposit, defeasance and discharge and will be subject to U.S. federal income tax on the same amount and in the same manner and at the same times as would have been the case if the deposit, defeasance and discharge had not occurred.

Defeasance of Certain Covenants. The indenture provides that, unless the terms of the applicable series of debt securities provide otherwise, upon compliance with certain conditions, we may omit to comply with the restrictive covenants contained in the indenture, as well as any additional covenants contained in a supplement to the indenture, a board resolution or an officers’ certificate delivered pursuant to the indenture. The conditions include:

Covenant Defeasance and Events of Default. In the event we exercise our option, as described above, not to comply with certain covenants of the indenture with respect to any series of debt securities and the debt securities of that series are declared due and payable because of the occurrence of any event of default, the amount of money and/or U.S. government obligations or foreign government obligations on deposit with the trustee will be sufficient to pay amounts due on the debt securities of that series at the time of their stated maturity but may not be sufficient to pay amounts due on the debt securities of that series at the time of the acceleration resulting from the event of default. However, we will remain liable for those payments.

“Foreign government obligations” means, with respect to debt securities of any series that are denominated in a currency other than U.S. dollars:

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.

DESCRIPTION OF WARRANTS WE MAY OFFER

As of January 15, 2016, we had warrants to purchase 445,000 shares of our common stock outstanding, held of record by two security holders. We typically issue warrants to purchase shares of our common stock to investors as part of a financing transaction, or in connection with services rendered by placement agents and outside consultants. Our outstanding warrants expire at varying dates through December 2020.

We may issue warrants to purchase debt securities, preferred stock, common stock or any combination of the foregoing. We may issue warrants independently or together with any other securities we offer under a prospectus supplement. The warrants may be attached to or separate from the securities. We will issue each series of warrants under a separate warrant agreement. The statements made in this section relating to the warrant agreement are summaries only. These summaries are not complete. When we issue warrants, we will provide the specific terms of the warrants and the applicable warrant agreement in a prospectus supplement and any related free writing prospectuses and such terms may differ from those described below. To the extent the information contained in the prospectus supplement differs from this summary description, you should rely on the information in the prospectus supplement.

Debt Warrants

We will describe in the applicable prospectus supplement and any related free writing prospectuses the terms of the debt warrants being offered, the warrant agreement relating to the debt warrants and the debt warrant certificates representing the debt warrants, including, as applicable:

As may be permitted under the warrant agreement, holders may exchange debt warrant certificates for new debt warrant certificates of different denominations, and may exercise debt warrants at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement and any related free writing prospectuses. Prior to the exercise of their debt warrants, holders of debt warrants will not have any of the rights of holders of the securities purchasable upon the exercise and will not be entitled to payments of principal, premium or interest on the securities purchasable upon the exercise of debt warrants.

Equity Warrants

We will describe in the applicable prospectus supplement and any related free writing prospectuses the terms of the preferred stock warrants or common stock warrants being offered, the warrant agreement relating to the preferred stock warrants or common stock warrants and the warrant certificates representing the preferred stock warrants or common stock warrants, including, as applicable:

Unless otherwise provided in the applicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses, holders of equity warrants will not be entitled, by virtue of being such holders, to vote, consent, receive dividends, receive notice as stockholders with respect to any meeting of stockholders for the election of our directors or any other matter, or to exercise any rights whatsoever as stockholders.

Except as provided in the applicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses, the exercise price payable and the number of shares and percentage of our outstandingcommon stock or preferred stock purchasable upon the exercise of each warrant will be subject to adjustment in certain events, including the issuance of a stock dividend to holders of common stock or preferred stock or a stock split, reverse stock split, combination, subdivision or reclassification of common stock or preferred stock. In lieu of adjusting the number of shares of common stock or preferred stock purchasable upon exercise of each warrant, we may elect to adjust the selling stockholder will own assuming allnumber of warrants. Unless otherwise provided in the applicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses, no adjustments in the number of shares purchasable upon exercise of the warrants will be required until all cumulative adjustments require an adjustment of at least 1% thereof. No fractional shares coveredwill be issued upon exercise of warrants, but we will pay the cash value of any fractional shares otherwise issuable. Notwithstanding the foregoing, except as otherwise provided in the applicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses, in case of any consolidation, merger, or sale or conveyance of our property as an entirety or substantially as an entirety, the holder of each outstanding warrant will have the right to the kind and amount of shares of stock and other securities and property, including cash, receivable by this prospectus are sold by the selling stockholder.

We do not know when or in what amounts the selling stockholder may sell or otherwise disposea holder of the number of shares of common stock covered hereby. The selling stockholder might not sell or disposepreferred stock into which each warrant was exercisable immediately prior to the particular triggering event.

Exercise of any or allWarrants

Each warrant will entitle the holder of the warrant to purchase for cash at the exercise price provided in the applicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses the principal amount of debt securities or shares covered by this prospectusof preferred stock or may sell or dispose of some or all of the shares other than pursuant to this prospectus. Because the selling stockholder may not sell or otherwise dispose of some or all of the shares covered by this prospectus and because there are currently no agreements, arrangements or understandings with respect to the sale or other disposition of any of the shares, we cannot estimate the number of shares that will be held by the selling stockholder after completion of the offering. However, for purposes of this table, we have assumed that all of the shares of common stock covered by this prospectus will be sold bybeing offered. Holders may exercise warrants at any time up to the selling stockholder.

The informationclose of business on the expiration date provided in the table is basedapplicable warrant agreement and corresponding prospectus supplement or any related free writing prospectuses. After the close of business on 65,296,580 shares outstandingthe expiration date, unexercised warrants are void.

Holders may exercise warrants as described in the applicable warrant agreement and corresponding prospectus supplement or any free writing prospectuses relating to the warrants being offered. Upon receipt of March 21, 2014payment and was prepared based on information supplied to us by the selling stockholder. Beneficial ownership is determined in accordance with Section 13(d)warrant certificate properly completed and duly executed at the corporate trust office of the Exchange Actwarrant agent or any other office indicated in the applicable warrant agreement and generally includes votingcorresponding prospectus supplement or investment power with respect toany related free writing prospectuses, we will, as soon as practicable, forward the debt securities, and including any securities that grant the selling stockholder the right to acquireshares of preferred stock or shares of common stock within 60 days of March 21, 2014. Other thanpurchasable upon the transactions referred to herein and in documents filed by us with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d)exercise of the Exchange Act,warrant. If less than all of the selling stockholder has not withinwarrants represented by the past three years hadwarrant certificate are exercised, we will issue a new warrant certificate for the remaining warrants.

DESCRIPTION OF UNITS WE MAY OFFER

This prospectus and any position, officeaccompanying prospectus supplement will contain the material terms and conditions for the units. As specified in the applicable prospectus supplement, units will be comprised of two or other material relationship with us ormore of the following securities in any of our predecessors or affiliates other than as a holder of our securities.combination: debt securities, preferred stock, common stock and warrants. You should refer to the applicable prospectus supplement for:

PLAN OF DISTRIBUTION

We may sell the offered securities from time to time.

The selling stockholder, including its transferees, pledgees, assignees, distributees, doneesapplicable prospectus supplement (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:

We may distribute the securities from time to time offer somein one or all of the shares of common stock covered by this prospectus. To the extent required, this prospectusmore transactions at:

The selling stockholder will not pay any of the costs, expenses and fees in connection with the registration of the shares covered by this prospectus, but it will pay any and all underwriting discounts, selling commissions and stock transfer taxes, if any, attributable to sales of the shares. We will not receive any proceeds from the sale of shares of our common stock covered by this prospectus.

The selling stockholder may sell the shares of common stock covered by this prospectus from time to time, and may also decide not to sell all or any of the shares of common stock that it is allowed to sell under this prospectus. The selling stockholder will act independently of us in making decisions regarding the timing, manner and size of each sale (subject to certain restrictions on sales volume contained in the Registration Rights and Stockholder Agreement). These dispositions may be at fixed prices, at

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

If we utilize an underwriter in the sale of the securities being offered, we will execute an underwriting agreement with the underwriter at the time of sale. Any underwriters used in the sale 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,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 at privately negotiated prices. Sales may be made by the selling stockholder in one or more types of transactions, which may include:

The selling stockholderdiscounts and commissions received by them and any profit realized by them on resale of the securities may also resell all or a portion of its common stock in open market transactions in reliance upon Rule 144be deemed to be underwriting discounts and commissions. We may enter into agreements to indemnify underwriters, dealers and agents against civil liabilities, including liabilities under the Securities Act, provided it meets the criteria and conformsor to the requirements of Rule 144.contribute to payments they may be required to make in respect thereof.

The selling stockholderIn addition, we may enter into sale, forward sale and derivative transactions with third parties (including the writing of options), or may sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with those sale, forward sale or derivative transactions,such a transaction, the third parties may, pursuant to this prospectus and the applicable prospectus supplement, sell securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions and by issuing securities that are not covered by this prospectus but are exchangeable for or represent beneficial interests insupplement. If so, the

common stock. The third parties alsoparty may use shares received under those sale, forward sale or derivative arrangements or shares pledged by the selling stockholder orsecurities borrowed from the selling stockholderus or others to settle such third-party sales orand may use securities received from us to close out any related open borrowings of common stock. Theshort positions. We may also loan or pledge securities covered by this prospectus and the applicable prospectus supplement to third parties, who may deliversell the loaned securities or, in an event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus in connection with any such transactions. Anyand the applicable prospectus supplement. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement (oror in a post-effective amendmentamendment.

All securities we offer, other than common stock, 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 registration statementliquidity of which this prospectus is a part).the trading markets for any securities.

In addition, the selling stockholderUnderwriters may engage in hedgingstabilizing and syndicate covering transactions in accordance with broker-dealers in connection with distributions of common stock or otherwise. In those transactions, broker-dealersRule 104 under the Exchange Act. Rule 104 permits stabilizing bids to purchase the securities being offered as long as the stabilizing bids do not exceed a specified maximum. Underwriters may engage in short sales ofover-allot the offered securities in the course of hedging the positions they assume with the selling stockholder. The selling stockholder may also sell securities short and redeliver securities to close out such short positions. The selling stockholder may also enter into option or other transactions with broker-dealers which require the delivery of securities to the broker-dealer. The broker-dealer may then resell or otherwise transfer such securities pursuant to this prospectus. The selling stockholder also may loan or pledge shares, and the borrower or pledgee may sell or otherwise transfer the common stock so loaned or pledged pursuant to this prospectus. Such borrower or pledgee also may transfer those shares of common stock to investors in our securities or the selling stockholder’s securities or in connection with the offering, thus creating a short position in their account. Syndicate covering transactions involve purchases of otherthe offered securities by underwriters in the open market after the distribution has been completed in order to cover syndicate short positions. Underwriters may also cover an over-allotment or short position by exercising their over-allotment option, if any. Stabilizing and syndicate covering transactions may cause the price of the offered securities to be higher than it would otherwise be in the absence of these transactions. These transactions, if commenced, may be discontinued at any time.

Any underwriters who are qualified market makers on the NASDAQ may engage in passive market making transactions in the securities on the NASDAQ 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 common stock. 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 coveredin 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.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by this prospectus.

Toany FINRA member or independent broker dealer may not exceed 8% of the extent necessary, we may amend or supplement this prospectus from time to time to describe a specific planaggregate amount of distribution. We will file a supplementthe securities offered pursuant to this prospectus if required, upon being notified by the selling stockholder thatand any material arrangement has been entered into with a broker-dealer for the sale of shares through a block trade, offering or a purchase by a broker or dealer. The applicable prospectus supplement will set forth the specific terms of the offering of securities, including:supplement.

The selling stockholder may, or may authorize underwriters, dealers and agents to, solicit offers from specified institutions to purchase common stock from the selling stockholder at the public offering price listed in the applicable prospectus supplement. These sales may be made under “delayed delivery contracts” or other purchase contracts that provide for payment and delivery on a specified future date. Any contracts like this will be described in and be subject to the conditions listed in the applicable prospectus supplement.

Broker-dealers or agents may receive compensation in the form of commissions, discounts or concessions from the selling stockholder. Broker-dealers or agents may also receive compensation from the purchasers of common stock for whom they act as agents or to whom they sell as principals, or both. Compensation as to a particular broker-dealer might be in excess of customary commissions and will be in amounts to be negotiated in connection with transactions involving securities. In effecting sales, broker-dealers engaged by the selling stockholder may arrange for other broker-dealers to participate in the resales.

In connection with sales of common stock covered hereby, the selling stockholder and any underwriter, broker-dealer or agent and any other participating broker-dealer that executes sales for the selling stockholder may be deemed to be an “underwriter” within the meaning of the Securities Act. Accordingly, any profits realized by the selling stockholder and any compensation earned by such underwriter, broker-dealer or agent may be deemed to be underwriting discounts and commissions. Because the selling stockholder may be deemed to be an “underwriter” under the Securities Act, the selling stockholder must deliver this prospectus and any prospectus supplement in the manner required by the Securities Act. This prospectus delivery requirement may be satisfied in accordance with Rule 153 under the Securities Act.

We and the selling stockholder have agreed to indemnify each other against certain liabilities, including liabilities under the Securities Act. In addition, we or the selling stockholder may agree to indemnify any underwriters, broker-dealers and agents against or contribute to any payments the underwriters, broker-dealers or agents may be required to make with

respect to, civil liabilities, including liabilities under the Securities Act. Underwriters, broker-dealers and agents and their affiliates are permitted to be customers of, engage in other transactions with us, or perform other services for us, and our affiliates or the selling stockholder or its affiliates in the ordinary course of their business.

The selling stockholder We will be subject todescribe such relationships in the applicable provisions of Regulation M ofprospectus supplement naming the Exchange Actunderwriter and the rules and regulations thereunder, which provisions may limit the timing of purchases and salesnature of any of the common stock by the selling stockholder. Regulation M may also restrict the ability of any person engaged in the distribution of the common stock to engage in market-making activities with respect to the common stock. These restrictions may affect the marketability of such common stock.relationship.

In order to comply with applicable securities laws of some states, the common stock may be sold in those jurisdictions only through registered or licensed brokers or dealers. In addition, in certain states the common stock may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirements is available. In addition, any common stock of a selling stockholder covered by this prospectus that qualify for sale pursuant to Rule 144 under the Securities Act may be sold in open market transactions under Rule 144 rather than pursuant to this prospectus.

In connection with an offering of common stock under this prospectus, underwriters may purchase and sell securities in the open market. These transactions may include short sales, stabilizing transactions and purchases to cover positions created by short sales. Short sales involve the sale by the underwriters of a greater number of securities than they are required to purchase in an offering. Stabilizing transactions consist of certain bids or purchases made for the purpose of preventing or retarding a decline in the market price of the securities while an offering is in progress.

The underwriters also may impose a penalty bid. This occurs when a particular underwriter repays to the underwriters a portion of the underwriting discount received by it because the underwriters have repurchased securities sold by or for the account of that underwriter in stabilizing or short-covering transactions.

These activities by the underwriters may stabilize, maintain or otherwise affect the market price of the common stock offered under this prospectus. As a result, the price of the common stock may be higher than the price that otherwise might exist in the open market. If these activities are commenced, they may be discontinued by the underwriters at any time. These transactions may be effected on the Nasdaq Global Select Market or another securities exchange or automated quotation system, or in the over-the-counter market or otherwise.

LEGAL MATTERS

The validity of the issuance of the shares of our common stocksecurities being offered by this prospectushereby will be passed upon for uson by Stradling Yocca Carlson & Rauth, a Professional Corporation, 660 Newport Center Drive, Suite 1600, Newport Beach, California.

EXPERTS

The consolidated financial statements, and the related financial statement schedule, incorporated in this prospectus by reference from the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, and the effectiveness of Spectrum Pharmaceuticals Inc.’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such financial statements and financial statement schedules have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the yearyears ended December 31, 2013 and the effectiveness of our internal control over financial reporting as of December 31, 2013,2012, as set forth in their reports thereon,report, which conclude, among other things, that Spectrum Pharmaceuticals, Inc. did not maintain effective internal control over financial reporting as of December 31, 2013, based on Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission, because of the effects of the material weakness described therein, included therein, and which areis 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 reports,report, given on their authority as experts in accounting and auditing. Effective March 17, 2014, Ernst & Young LLP is no longer our independent registered public accounting firm.

WHERE YOU CAN FIND MORE INFORMATION

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

We file annual, quarterly and otherspecial reports, proxy statements and other information with the Commission. Our Commission filings are available toSEC under the public over the Internet at the Commission’s website at http://www.sec.gov.Exchange Act. You may also read and copy any document we filethis information at the Commission’sfollowing SEC location:

Public Reference Room

100 F Street, N.E.

Washington, D.C. 20549

You may obtain information on the operation of the Public Reference Room by calling the SEC at 100 F Street, NE, Washington, D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further(800) SEC-0330. The SEC also maintains a web site that contains reports, proxy statements, information on the Public Reference Room. Our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and Current Reports on Form 8-K, including any amendments to those reports,statements and other information that weabout issuers, like Spectrum Pharmaceuticals, Inc., who file with or furnish to the Commission pursuant to Section 13(a) or 15(d) of the Exchange Act can also be accessed free of charge through the Internet. These filings will be available as soon as reasonably practicable after we electronically file such material with, or furnish it to, the Commission.

We have filed with the Commission a registration statement underSEC. The address of that web site is www.sec.gov.

In addition, our common stock is listed on the Securities Act relating to the offering of these securities. The registration statement, including the attached exhibits, contains additional relevantNASDAQ and similar information aboutconcerning us can be inspected and the securities. This prospectus does not contain all of the information set forth in the registration statement. You can obtain a copy of the registration statement, at prescribed rates, from the Commissioncopied at the address listed above.offices of The registration statement and the documents referred to below under “Incorporation of Certain Information by Reference” are also available on our Internet websites located at http://www.sppirx.com and http://www.spectrumpharm.com. We have not incorporated by reference into this prospectus the information on our websites, and you should not consider such information to be a part of this prospectus.Nasdaq Stock Market, One Liberty Plaza, 165 Broadway, New York, NY 10006.

INCORPORATION OF CERTAIN INFORMATIONDOCUMENTS BY REFERENCE

The CommissionSEC allows us to incorporate“incorporate by referencereference” information into this prospectus certain information that we file with it, whichprospectus. This means that we can disclose important information about us and our financial condition to you by referring you to those documents.another document filed separately with the SEC. The information incorporated by reference is considered to be a part of this prospectus. This prospectus and information that we file later with the Commission will automatically update and supersede information contained in this prospectus. We incorporateincorporates by reference the documents listed below that we have previously filed with the Commission (excluding any portions of any Form 8-K that are not deemed “filed” pursuant to the General Instructions of Form 8-K):SEC:

We also incorporate by reference into this prospectus additionalall documents that we may filefiled by us with the Commission underSEC pursuant to Sections 13(a)12(a), 13(c), 14 or 15(d) of the Exchange Act prior to the completion or termination of theany offering of securities made by this prospectus, including all such documents we may file with the CommissionSEC after the filingdate of the initial registration statement and prior to the effectiveness of the registration statement, but excluding anystatement. Nothing in this prospectus shall be deemed to incorporate information deemed “furnished”furnished but not “filed”filed with the Commission. SEC (including without limitation, information furnished under Item 2.02 or Item 7.01 of Form 8-K, and any exhibits relating to such information).

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

You may request a copy of the filings incorporated herein by reference, including exhibits to such documents that statement.

We will provide to each person, including any beneficial owner, to whom this prospectus is delivered, upon written or oral request,are specifically incorporated by reference, at no cost, toby writing or calling us at the requester, a copy of any and all of the information that is incorporated by reference in this prospectus. Requests for such documents should be directed to:following address or telephone number:

Spectrum Pharmaceuticals, Inc.

11500 South Eastern Avenue, Suite 240

Henderson, Nevada 89052

Telephone: (702) 835-6300

Attention: Investor Relations

Statements contained in this prospectus as to the contents of any contract or other documentdocuments are not necessarily complete, and in each instance investors are referred to the copy of the contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference and the exhibits and schedules thereto.

$250,000,000

Debt Securities

1,000,000 Shares of Preferred Stock

Common Stock

Warrants

Units

PROSPECTUS

, 20142016

The information in this prospectus is not complete and may be changed. We may not sell these securities or accept an offer to buy these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities, and it is not soliciting offers to buy these securities in any state where such offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JANUARY 25, 2016

PROSPECTUS

Up to $100,000,000 of Shares

Common Stock

This prospectus relates to the issuance and sale of up to $100,000,000 of shares of our common stock from time to time through our sales agents, FBR Capital Markets & Co., or FBR, MLV & Co. LLC, or MLV, and H.C. Wainwright & Co., LLC, or HCW, collectively, the “sales agents.” These sales, if any, will be made pursuant to the terms of the At Market Issuance Sales Agreement, as amended, or the sales agreement, among us and the sales agents, which is filed with the Securities and Exchange Commission, or the SEC, as an exhibit to the registration statement of which this prospectus is part.

Our common stock is traded on the Nasdaq Global Select Market, or the NASDAQ, under the symbol “SPPI.” On January 15, 2016, the closing sale price of our common stock on NASDAQ was $4.98 per share.

Sales of shares of our common stock under this prospectus, if any, may be made by any method deemed to be an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended, or the Securities Act, including sales made directly on or through the NASDAQ, the existing trading market for our common stock or sales made to or through a market maker other than on an exchange. The sales agents are not required to sell any specific number of shares of our common stock. Each of the sales agents have agreed to use its commercially reasonable efforts consistent with its normal trading and sales practices, on mutually agreed terms among the sales agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

The sales agents will be entitled to compensation under the terms of the sales agreement at a commission rate of up to 3.0% of the gross proceeds of the sales price of common stock that they sell. The net proceeds from any sales under this prospectus will be used as described under “Use of Proceeds.” The proceeds we receive from sales of our common stock, if any, will depend on the number of shares actually sold and the offering price of such shares.

In connection with the sale of common stock on our behalf, each of FBR, MLV, and HCW will be deemed to be an underwriter within the meaning of the Securities Act, and the compensation of the sales agents will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the sales agents with respect to certain liabilities, including liabilities under the Securities Act.

Investing in our securities involves a high degree of risk. You should read carefully and consider the information contained in and incorporated by referenced under “Risk Factors” beginning on page SA-4 of this prospectus, and the risk factors contained in other documents incorporated by reference.

Neither the SEC 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                     , 2016.

ABOUTTHIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the SEC utilizing a “shelf” registration process. Under the shelf registration process, we may offer shares of our common stock having an aggregate offering price of up to $100,000,000 from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of offering.

This prospectus and the documents incorporated into each by reference include important information about us, the shares being offered and other information you should know before investing in our common stock. To the extent there is a conflict between the information contained in this prospectus, on the one hand, and the information contained in any document incorporated by reference into this prospectus that was filed with the SEC before the date of this prospectus, on the other hand, you should rely on the information in this prospectus.

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 herein 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 agreement, 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.

You should rely on this prospectus and the information incorporated or deemed to be incorporated by reference in this prospectus. We have not, and the sales agents have not, authorized anyone to provide you with information that is in addition to or different from that contained or incorporated by reference in this prospectus. We and each of FBR, MLV, and HCW take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. Neither we nor any of the sales agents are offering to sell these securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained or incorporated by reference in this prospectus is accurate as of any date other than as of the date of this prospectus or in the case of the documents incorporated by reference, the date of such documents regardless of the time of delivery of this prospectus or any sale of our common stock. Our business, financial conditions, liquidity, results of operations and prospects may have changed since those dates.

Unless otherwise indicated or the context otherwise requires, the terms “Company,” “Spectrum Pharmaceuticals,” “we,” “us” and “our” refer to Spectrum Pharmaceuticals, Inc., a Delaware corporation, and its predecessors and consolidated subsidiaries.

SA - 1

SA - 2

SA - 3

RISK FACTORS

Before making an investment decision, you should carefully consider the risks described below and discussed in the section titled “Risk Factors” in our most recent Annual Report on Form 10-K, as well as the risks, uncertainties and additional information set forth in our SEC reports on Forms 10-K, 10-Q and 8-K and in other documents incorporated by reference in this prospectus. 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. These updated Risk Factors will be incorporated by reference in this prospectus. Our business, financial condition or results of operations could be materially adversely affected by any of these risks. The trading price of our common stock could decline due to any of these risks, and you may lose all or part of your investment.

Risks Related to This Offering

Management will have broad discretion as to the use of the proceeds from this offering and may not use the proceeds effectively.

Because we have not designated the amount of net proceeds from this offering to be used for any particular purpose, our management will have broad discretion as to the application of the net proceeds from this offering and could use them for purposes other than those contemplated at the time of the offering. Our management may use the net proceeds for corporate purposes that may not improve our financial condition or market value

Future sales of substantial amounts of our common stock, or the possibility that such sales could occur, could adversely affect the market price of our common stock.

We may issue up to $100,000,000 of common stock from time to time in this offering. The issuance from time to time of shares in this offering, as well as our ability to issue such shares in this offering, could have the effect of depressing the market price or increasing the market price volatility of our common stock. See “Plan of Distribution” on page SA-10 of this prospectus for more information about the possible adverse effects of our sales under the sales agreement.

You may experience immediate and substantial dilution.

The offering price per share in this offering may exceed the net tangible book value per share of our common stock. Assuming that an aggregate of 20,080,322 shares of our common stock are sold at a price of $4.98 per share pursuant to this prospectus which was the last reported sale price of our common stock on the NASDAQ on January 15, 2016, for aggregate gross proceeds of $97,000,000 after deducting commissions and estimated aggregate offering expenses payable by us, you would experience immediate dilution of $1.26 per share, representing a difference between our as adjusted net tangible book value per share as of September 30, 2015 after giving effect to this offering and the assumed offering price. The exercise of outstanding stock options and warrants may result in further dilution of your investment. See the section entitled “Dilution” on page SA-6 of this prospectus for a more detailed illustration of the dilution you would incur if you participate in this offering.

SA - 4

NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference into this prospectus contains certain forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act, in reliance upon the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Forward-looking statements include, without limitation, statements regarding the success, safety and efficacy of our drug products, product approvals, product sales, revenues, development timelines, product acquisitions, liquidity and capital resources and trends, and other statements containing forward-looking words, such as, “believes,” “may,” “could,” “would,” “will,” “expects,” “intends,” “estimates,” “anticipates,” “plans,” “seeks,” or “continues” or the negative thereof or variation thereon or similar terminology (although not all forward-looking statements contain these words). Such forward-looking statements are based on the beliefs of our management as well as assumptions made by and information currently available to our management. Readers should not put undue reliance on these forward-looking statements. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified; therefore, our actual results may differ materially from those described in any forward-looking statements. The risks and uncertainties include those noted in our SEC filings or any applicable prospectus supplement.

We urge you to consider these factors carefully in evaluating the forward-looking statements contained in this prospectus and any prospectus supplement. All subsequent written or oral forward-looking statements attributable to our company or persons acting on our behalf are expressly qualified in their entirety by these cautionary statements. The forward-looking statements included in this prospectus are made only as of the date of this prospectus. We undertake no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise, except to the extent that we are required to do so by law.

SA - 5

USE OF PROCEEDS

The amount of proceeds from this offering will depend upon the number of shares of our common stock sold and the market price at which they are sold. There can be no assurance that we will be able to sell any shares under or fully utilize the sales agreement with FBR, MLV, and HCW.

We intend to use the net proceeds from this offering for general corporate purposes, including, without limitation, sales and marketing activities, clinical development, making acquisitions of assets, businesses, companies or securities, capital expenditures and for working capital. We may temporarily invest the net proceeds in short-term, interest-bearing instruments or other investment-grade securities. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

DILUTION

If you invest in our common stock, your ownership interest will be diluted to the extent of the difference between the public offering price per share and the as-adjusted net tangible book value per share after this offering. We calculate net tangible book value per share by dividing the net tangible book value, which is tangible assets less total liabilities, by the number of outstanding shares of our common stock.

After giving effect to the sale of our common stock pursuant to this prospectus in the aggregate amount of $100 million at an assumed offering price of $4.98 per share, the last reported sale price of our common stock on the NASDAQ on January 15, 2016, and after deducting commissions and estimated aggregate offering expenses payable by us, our net tangible book value as of September 30, 2015 would have been $325,454,000, or $3.72 per share of common stock. This represents an immediate increase in the net tangible book value of $0.33 per share to our existing stockholders and an immediate dilution in net tangible book value of $1.26 per share to new investors. The following table illustrates this per share dilution:

The above discussion and table are based on approximately 67,314,580 shares of our common stock outstanding as of September 30, 2015 and excludes the following:

SA - 6

PRICE RANGE OF COMMON STOCK

Our common stock is listed on the NASDAQ under the symbol “SPPI.” The following table shows the high and low per share closing sale prices of our common stock for the periods indicated.

On January 15, 2016, the closing price of our common stock on the NASDAQ was $4.98 per share, and there were 399 holders of record of our common stock.

DIVIDEND POLICY

We do not currently anticipate declaring or paying cash dividends on our capital stock in the foreseeable future. We currently intend to retain all of our future earnings, if any, to finance the operation and expansion of our business. Any future determination relating to our dividend policy will be made at the discretion of our board of directors and will depend on a number of factors, including future earnings, capital requirements, future prospects, contractual restrictions and covenants and other factors that our board of directors may deem relevant.

SA - 7

DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock is intended as a summary only and therefore is not a complete description of our capital stock. This description is based upon, and is qualified by reference to, our certificate of incorporation as amended, or amended certificate of incorporation, our second amended and restated bylaws, or amended bylaws and applicable provisions of Delaware corporate law. You should read our amended certificate of incorporation and amended bylaws, which are filed as exhibits to the registration statement of which this prospectus forms a part, for the provisions that are important to you.

General

Our authorized capital stock consists of 175,000,000 shares of common stock, par value $0.001 per share, and 5,000,000 shares of preferred stock, par value $0.001 per share.

Common Stock

As of January 15, 2016, there were 68,172,919 shares of common stock outstanding. The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders. The holders of common stock are not entitled to cumulative voting rights with respect to the election of directors, and as a consequence, minority stockholders will not be able to elect directors on the basis of their votes alone.

Subject to preferences that may be applicable to any then outstanding shares of preferred stock, holders of common stock are entitled to receive ratably such dividends as may be declared by the board of directors out of funds legally available therefor. In the event of a liquidation, dissolution or winding up of us, holders of the common stock are entitled to share ratably in all assets remaining after payment of liabilities and the liquidation preferences of any then outstanding shares of preferred stock. Holders of common stock have no preemptive rights and no right to convert their common stock into any other securities. There are no redemption or sinking fund provisions applicable to our common stock. All outstanding shares of common stock are, and all shares of common stock to be issued under this prospectus will be, fully paid and non-assessable. The rights, preferences and privileges of holders of our common stock are subject to, and may be adversely affected by, the rights of the holders of shares of any of our outstanding preferred stock.

Listing

Our common stock is listed under the symbol “SPPI” on the NASDAQ.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

Stockholder Rights Plan

On December 13, 2010, we adopted a Stockholder Rights Plan pursuant to which we have distributed rights to purchase units of our Series B Junior Participating Preferred Stock. The rights become exercisable upon the earlier of ten days after a person or group of affiliated or associated persons has acquired 15% or more of the outstanding shares of our common stock or ten business days after a tender offer has commenced that would result in a person or group beneficially owning 15% or more of our outstanding common stock, other than pursuant to a transaction approved in advance by our Board of Directors. The description and terms of the rights are set forth in a Rights Agreement between us and ComputerShare Trust Company, N.A., as rights agent.

Preferred Stock

We are authorized to issue a total of 5,000,000 shares of preferred stock. Of the 5,000,000 authorized shares of preferred stock, we are authorized to issue 1,500,000 shares of Series B Junior Participating Preferred Stock and 2,000 shares of Series E Convertible Voting Preferred Stock. As of January 15, 2016, 20 shares of Series E Convertible Voting Preferred Stock were issued and outstanding. These shares are convertible into 40,000 shares of common stock. There are no dividends payable on the Series E Convertible Voting Preferred Stock.

SA - 8

Each share of Series E Convertible Voting Preferred Stock has a liquidation preference equal to 120% of the stated value of $10,000 plus any declared and unpaid dividends on such share, subject to adjustment in certain circumstances.

Holders of our Series E Convertible Voting Preferred Stock have full voting rights and powers equal to the voting rights and powers of holders of common stock, and are entitled to the number of votes equal to the number of shares of common stock into which their shares of Series E Convertible Voting Preferred Stock can be converted. Pursuant to the Certificate of Designation for the Series E Convertible Voting Preferred Stock, the number of shares of our common stock that may be acquired by any holder of Series E Convertible Voting Preferred Stock upon any conversion of the preferred stock, or that shall be entitled to voting rights, is limited to the extent necessary to ensure that following such conversion, the number of shares of our common stock then beneficially owned by such holder and any other person or entities whose beneficial ownership of common stock would be aggregated with the holder’s for purposes of the Exchange Act does not exceed 4.95% of the total number of shares of our common stock then outstanding.

Preferred stock may be issued from time to time, in one or more series, with specified rights, powers, preferences and limitations, as authorized by the board of directors.

Anti-Takeover Provisions

Our amended certificate of incorporation and amended and restated bylaws contain provisions that, together with the ownership position of the officers, directors and their affiliates, could discourage potential takeover attempts and make it more difficult for stockholders to change management, which could adversely affect the market price of our common stock.

Our amended certificate of incorporation limits the extent to which our directors are personally liable to us and our stockholders, to the fullest extent permitted by the Delaware General Corporation Law, or DGCL. The inclusion of this provision in our amended certificate of incorporation may reduce the likelihood of derivative litigation against directors and may discourage or deter stockholders or management from bringing a lawsuit against directors for breach of their duty of care.

Our amended and restated bylaws provide that special meetings of stockholders can be called only by the board of directors, the chairman of the board of directors or the chief executive officer. Stockholders are not permitted to call a special meeting and cannot require the board of directors to call a special meeting. There is no right of stockholders to act by written consent without a meeting, unless the consent is unanimous. Any vacancy on the board of directors resulting from death, resignation, removal or otherwise or newly created directorships may be filled only by vote of the majority of directors then in office, or by a sole remaining director. Our amended and restated bylaws establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, except for nominations made by or at the direction of the board of directors or a committee of the board.

In addition to our rights plan, our amended certificate of incorporation and our amended and restated bylaws, certain provisions of Delaware law may make the acquisition of the company by tender offer, a proxy contest or otherwise, or the removal of our officers and directors, more difficult. For example, we are subject to the “business combination” statute of the DGCL. Section 203 of the DGCL prohibits certain publicly-held Delaware corporations from engaging in a business combination with an interested stockholder for a period of three years following the time such person became an interested stockholder unless the business combination is approved in a specified manner. Generally, an interested stockholder is a person who, together with its affiliates and associates, owns 15% or more of the corporation’s voting stock, or is affiliated with the corporation and owns or owned 15% of the corporation’s voting stock within three years before the business combination.

SA - 9

PLAN OF DISTRIBUTION

We have entered into a sales agreement with FBR, MLV, and HCW, on December 23, 2015 under which we may offer and sell up to $100,000,000 of shares of our common stock from time to time through the sales agents, acting as agents. Sales of shares of our common stock, if any, under this prospectus may be made in negotiated transactions or transactions that are deemed to be “at the market offerings” as defined in Rule 415 under the Securities Act, including, without limitation, sales made directly on the NASDAQ or any other existing trading market for our common stock or sales made to or through a market maker other than on an exchange.

Under the terms of the sales agreement, we may also sell our common stock to either or all of the sales agents, as principals for their own accounts, at a price negotiated at the time of sale. If we sell shares to any sales agent in this manner, we will enter into a separate agreement setting forth the terms of such transaction, and we will describe the agreement in a separate prospectus supplement or pricing supplement.

We will pay the sales agents commissions for their services in acting as agents in the sale of our common stock at a commission rate of up to 3.0% of the gross sale price per share sold. We estimate that the total expenses for the offering, excluding compensation and reimbursements payable to the sales agents under the sales agreement, will be approximately $90,000. We have also agreed to reimburse the sales agents their reasonable out-of-pocket expenses, including attorney’s fees, in an amount not to exceed $25,000.

Settlement for sales of common stock will occur on the third business day following the date on which any sales are made, or on some other date that is agreed upon by us and the sales agents 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.

In connection with the sale of the common stock on our behalf, each of FBR, MLV, and HCW will be deemed to be an underwriter within the meaning of the Securities Act, and the compensation of the sales agents will be deemed to be underwriting commissions or discounts. We have agreed to provide indemnification and contribution to the sales agents against certain civil liabilities, including liabilities under the Securities Act.

The offering pursuant to the sales agreement will terminate upon the earlier of (1) the issuance and sale of all shares or our common stock subject to the sales agreement; and (2) the termination of the sales agreement as permitted therein.

MLV is an affiliate of FBR Capital Markets & Co.

The prospectus in electronic format may be made available on websites maintained by each sales agent.

The sales agents and their affiliates have in the past and 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, the sales agents will not engage in any market making activities involving our 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. A copy of the sales agreement is filed as an exhibit to the registration statement of which this prospectus forms a part and is incorporated by reference in this prospectus.

LEGAL MATTERS

Certain legal matters will be passed upon for us by Stradling Yocca Carlson & Rauth, a Professional Corporation, Newport Beach, California. Certain legal matters will be passed upon for FBR, MLV, and HCW by LeClairRyan, A Professional Corporation, New York, New York.

EXPERTS

The consolidated financial statements, and the related financial statement schedule, incorporated in this prospectus by reference from the Company’s Annual Report on Form 10-K for the year ended December 31, 2014, and the effectiveness of Spectrum Pharmaceuticals Inc.’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports, which are incorporated herein by reference. Such financial statements and financial statement schedules have been so incorporated in reliance upon the reports of such firm given upon their authority as experts in accounting and auditing.

SA - 10

Ernst & Young LLP, independent registered public accounting firm, has audited our consolidated financial statements included in our Annual Report on Form 10-K for the years ended December 31, 2013 and 2012, 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 on Form S-3 that we filed with the SEC registering the securities that may be offered and sold hereunder. The registration statement, including exhibits thereto, contains additional relevant information about us and these securities that, as permitted by the rules and regulations of the SEC, we have not included in this prospectus. A copy of the registration statement can be obtained at the address set forth below. You should read the registration statement for further information about us and these securities.

We file annual, quarterly and special reports, proxy statements and other information with the SEC under the Exchange Act. You may read and copy this information at the following SEC location:

Public Reference Room

100 F Street, N.E.

Washington, D.C. 20549

You may obtain information on the operation of the Public Reference Room by calling the SEC at (800) SEC-0330. The SEC also maintains a web site that contains reports, proxy statements, information statements and other information about issuers, like Spectrum Pharmaceuticals, Inc., who file electronically with the SEC. The address of that web site is www.sec.gov.

In addition, our common stock is listed on the NASDAQ and similar information concerning us can be inspected and copied at the offices of The Nasdaq Stock Market, One Liberty Plaza, 165 Broadway, New York, NY 10006.

SA - 11

INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

This prospectus is part of a registration statement on Form S-3 filed by us with the SEC. This prospectus does not contain all of the information set forth in the registration statement, certain parts of which are omitted in accordance with the rules and regulations of the SEC. For further information about us and the securities offered by this prospectus, we refer you to the registration statement and its exhibits and schedules which may be obtained as described herein.

The SEC allows us to “incorporate by reference” information into this prospectus. This means that we can disclose important information about us and our financial condition to you by referring you to another document filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus. This prospectus incorporates by reference the documents listed below that we have previously filed with the SEC:

We also incorporate by reference into this prospectus all documents filed by us with the SEC pursuant to Sections 12(a), 13(c), 14 or 15(d) of the Exchange Act prior to the termination of any offering of securities made by this prospectus, including all such documents we may file with the SEC after the date of the initial registration statement and prior to the effectiveness of the registration statement. Nothing in this prospectus shall be deemed to incorporate information furnished but not filed with the SEC (including without limitation, information furnished under Item 2.02 or Item 7.01 of Form 8-K, and any exhibits relating to such information).

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

You may request a copy of the filings incorporated herein by reference, including exhibits to such documents that are specifically incorporated by reference, at no cost, by writing or calling us at the following address or telephone number:

Spectrum Pharmaceuticals, Inc.

11500 South Eastern Avenue, Suite 240

Henderson, Nevada 89052

Telephone: (702) 835-6300

Attention: Investor Relations

SA - 12

Statements contained in this prospectus as to the contents of any contract or other documents are not necessarily complete, and in each instance investors are referred to the copy of the contract or other document filed as an exhibit to the registration statement, each such statement being qualified in all respects by such reference and the exhibits and schedules thereto.

SA - 13

$100,000,000

Common Stock

PROSPECTUS

, 2016

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

The following table sets forth all costs and expenses, other than underwriting discounts and commissions, payable by us in connection with the sale of the common stock being registered hereunder. All of the amounts shown shall be paid by us and are estimates except for the SEC registration fee. All of the amounts shown will be paid by us.fee, which was previously paid.

Item 15. Indemnification of Directors and Officers.

We are a Delaware corporation. Section 145(a) of the Delaware General Corporation Law, or the DGCL, provides that a Delaware corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative, other than an action by or in the right of the corporation, by reason of the fact that such person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against expenses (including attorney fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit or proceeding if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, had no reasonable cause to believe his or her conduct was unlawful.

Section 145(b) of the DGCL provides that a Delaware corporation may indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that such person acted in any of the capacities set forth above, against expenses actually and reasonably incurred by such person in connection with the defense or settlement of such action or suit if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification shall be made in respect of any claim, issue or matter as to which such person shall have been adjudged to be liable to the corporation, unless and only to the extent that the Court of Chancery or the court in which such action or suit was brought shall determine that, despite the adjudication of liability but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses which the court shall deem proper.

Further subsections of DGCL Section 145 provide that:

(1) to the extent a present or former director or officer of a corporation has been successful on the merits or otherwise in the defense of any action, suit or proceeding referred to in subsections (a) and (b) of Section 145 or in the defense of any claim, issue or matter therein, such person shall be indemnified against expenses, including attorneys’ fees, actually and reasonably incurred by such person in connection therewith;

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(2) the indemnification and advancement of expenses provided for pursuant to Section 145 shall not be deemed exclusive of any other rights to which those seeking indemnification or advancement of expenses may be entitled under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise; and

(3) the corporation shall have the power to purchase and maintain insurance on behalf of any person who is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another corporation, partnership, joint venture, trust or other enterprise, against any liability asserted against such person and incurred by such person in any such capacity, or arising out of such person’s status as such, whether or not the corporation would have the power to indemnify such person against such liability under Section 145.

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Section 145 of the DGCL makes provision for the indemnification of officers and directors in terms sufficiently broad to indemnify our officers and directors under certain circumstances from liabilities (including reimbursement for expenses incurred) arising under the Securities Act of 1933. Our amended certificate of incorporation and amended and restated bylaws provide, in effect, that, to the fullest extent and under the circumstances permitted by Section 145 of the DGCL, we will indemnify any person (and the estate of any person) who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative, by reason of the fact that he or she is or was a director or officer of our company or is or was serving at our request as a director or officer of another corporation or enterprise. We may, in our discretion, similarly indemnify its employees and agents.

We have entered into indemnification agreements with our officers and directors.

Our amended and restated bylaws relieve our directors from monetary damages to us or our stockholders for breach of such director’s fiduciary duty as a director to the fullest extent permitted by the DGCL. Under Section 102(b)(7) of the DGCL, a corporation may relieve its directors from personal liability to such corporation or its stockholders for monetary damages for any breach of their fiduciary duty as directors except (i) for a breach of the duty of loyalty, (ii) for acts or omissions not in good faith, or which involve intentional misconduct or a knowing violation of law, (iii) for willful or negligent violations of certain provisions in the DGCL imposing certain requirements with respect to stock repurchases, redemptions and dividends, or (iv) for any transactions from which the director derived an improper personal benefit.

We currently maintain an insurance policy which, within the limits and subject to the terms and conditions thereof, covers certain expenses and liabilities that may be incurred by directors and officers in connection with proceedings that may be brought against them as a result of an act or omission committed or suffered while acting as a director or officer of our company.

Item 16. Exhibits and Financial Statement Schedules.

See the Exhibit Index attached to this registration statement and incorporated herein by this reference.

Item 17. Undertakings.Undertakings.

(a) The undersigned registrant hereby undertakes:

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

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

(ii) To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or any decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form

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of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement; and

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

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

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

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

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

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

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

(5) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of the securities, in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

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

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

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

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

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

(c) The undersigned registrant hereby undertakes to deliver or cause to be delivered with the prospectus, to each person to whom the prospectus is sent or given, the latest annual report, to security holders that is incorporated by reference in the prospectus and furnished pursuant to and meeting the requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of 1934; and, where interim financial information required to be presented by Article 3 of Regulation S-X is not set forth in the prospectus, to deliver, or cause to be delivered to each person to whom the prospectus is sent or given, the latest quarterly report that is specifically incorporated by reference in the prospectus to provide such interim financial information.

(d) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrantregistrants pursuant to the foregoing provisions described in Item 15, or otherwise, the registrant hasregistrants have been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrantregistrants of expenses incurred or paid by a director, officer or controlling person of theany registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, theeach appropriate registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

(d) The undersigned registrants hereby undertake to file an application for the purpose of determining the eligibility of the trustee to act under subsection (a) of section 310 of the Trust Indenture Act in accordance with the rules and regulations prescribed by the Commission under section 305(b)(2) of the Trust Indenture Act.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrantRegistrant certifies that isit has reasonable grounds to believe that it meets all of the requirements for filing on Form S-3 and has duly caused this registration statementAmendment No. 1 to Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Henderson, State of Nevada, on theJanuary 25, day of March, 2014.2016.

POWER OF ATTORNEY

We, the undersigned directors and officers of Spectrum Pharmaceuticals, Inc. do hereby constitute and appoint Rajesh C. Shrotriya and Kurt A. Gustafson, and each of them, individually, our true and lawful attorneys-in-fact and agents, each with full power to sign for us or any of us in our names and in any and all capacities, any and all amendments (including post-effective amendments) to this Registration Statement, or any related registration statement that is to be effective upon filing pursuant to Rule 462 under the Securities Act of 1933, as amended, and to file the same, with all exhibits thereto and other documents required in connection therewith, and each of them with full power to do any and all acts and things in our names and in any and all capacities, which such attorneys-in-fact and agents and, any of them, individually, may deem necessary or advisable to enable Spectrum Pharmaceuticals, Inc. to comply with the Securities Act of 1933, as amended, and any rules, regulations, and requirements of the Securities and Exchange Commission, in connection with this Registration Statement; and we hereby do ratify and confirm all that such attorneys-in-fact and agents, or any of them, shall do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act of 1933, this Amendment No. 1 to Registration Statement has been signed by the following persons in the capacities and on the datesdate indicated.

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EXHIBIT INDEX

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