SPECTRUM PHARMACEUTICALS, INC. WARRANT

Exhibit 4.1

THIS WARRANT AND THE SECURITIES REPRESENTED HEREBY OR ACQUIRABLE UPON EXERCISE HEREOF HAVE NOT REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE OFFERED, SOLD, ASSIGNED OR TRANSFERRED, IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SAID ACT OR UNLESS THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY THAT REGISTRATION UNDER SAID ACT IS NOT REQUIRED.

SPECTRUM PHARMACEUTICALS, INC.

WARRANT

Spectrum Pharmaceuticals, Inc., a Delaware corporation (the “Company”), hereby certifies that, for value received, John T. Moore or his registered assigns (“Holder”), is entitled, subject to the terms set forth below, to purchase from the Company up to a total of 50,000 shares of Common Stock, $.001 par value per share (the “Common Stock”), of the Company (each such share, a “Warrant Share” and all such shares, the “Warrant Shares”) at an exercise price equal to $1.79 per share (as adjusted from time to time as provided in Section 7, the “Exercise Price”), at any time from and including April 28, 2008 (the “Effective Date”) through and including April 27, 2013 (the “Expiration Date”), in accordance with the vesting schedule set forth in Section 3 (b), subject to the following terms and conditions:

1. Registration of Warrant. The Company shall register this Warrant upon records to be maintained by the Company for that purpose (the “Warrant Register”), in the name of the record Holder hereof from time to time. The Company may deem and treat the registered Holder of this Warrant as the absolute owner hereof for the purpose of any exercise hereof or any distribution to the Holder, and for all other purposes, and the Company shall not be affected by notice to the contrary.

2. Registration of Transfers and Exchanges.

(a) This Warrant may not be sold, transferred, assigned, pledged, hypothecated or otherwise disposed, directly or indirectly, in whole or in part, without the prior written consent of the Company. Any attempted sale, transfer, assignment, pledge, hypothecation or other disposition of this Warrant, or any portion thereof, shall be void and without any force or effect; provided, however, that, subject to compliance with any applicable securities laws, the Holder may transfer this Warrant, or any portion thereof, without the prior written consent of the Company, if such transfer is to (i) a spouse, child, grandchild, parent, sibling or custodian or trustee for the benefit of any such relatives, or (ii) any shareholder or affiliate entity.

(b) The Company shall register the transfer of any portion of this Warrant in conformance with Section 2(a) in the Warrant Register, upon surrender of this Warrant, with the Form of Assignment attached hereto duly completed and signed, to the Company at the office specified in or pursuant to Section 10. Upon any such registration or transfer, a new warrant to purchase Common Stock, in substantially the form of this Warrant (any such new warrant, a “New Warrant”), evidencing the portion of this Warrant so transferred shall be issued to the transferee and a New Warrant evidencing the remaining portion of this Warrant not so transferred, if any, shall be issued to the transferring Holder. The acceptance of the New Warrant by the transferee thereof shall be deemed the acceptance of such transferee of all of the rights and obligations of a holder of this Warrant.

(c) This Warrant is exchangeable, upon the surrender hereof by the Holder to the office of the Company specified in or pursuant to Section 10 for one or more New Warrants, evidencing in the aggregate the right to purchase the number of Warrant Shares which may then be purchased hereunder.

(d) Unless the resale of the Warrant Shares has been registered under the Securities Act of 1933, as amended, each certificate for Warrant Shares initially issued upon the exercise of this Warrant, and each certificate for Warrant Shares issued to any subsequent transferee of any such certificate, shall be stamped or otherwise imprinted with a legend in substantially the following form:

“THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933 AS AMENDED, AND MAY NOT BE OFFERED, SOLD, ASSIGNED OR TRANSFERRED, IN THE ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER SAID ACT OR UNLESS THE COMPANY HAS RECEIVED AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE COMPANY THAT REGISTRATION UNDER SAID ACT IS NOT REQUIRED.”

3. Duration and Exercise of Warrant.

(a) This Warrant shall be exercisable by the then registered Holder on any business day before 5:00 P.M., California time, at any time and from time to time on or after the Effective Date to and including the Expiration Date. At 5:00 P.M., California time on the Expiration Date, the portion of this Warrant not exercised prior thereto shall be and become void and of no value.

(b) This Warrant shall vest in accordance with the following schedule:

(c ) Upon surrender of this Warrant, with the Form of Election to Purchase attached hereto duly completed and signed, to the Company at its address for notice set forth in Section 10 and upon payment of the Exercise Price multiplied by the number of Warrant Shares that the Holder intends to purchase hereunder, in the manner provided hereunder, all as specified by the Holder in the Form of Election to Purchase, the Company shall promptly (and in any event, within four business days) issue or cause to be issued and cause to be delivered to or upon the written order of the Holder and in such name or names as the Holder may designate, a certificate for the Warrant Shares issuable upon such exercise. Any person so designated by the Holder to receive Warrant Shares shall be deemed to have become holder of record of such Warrant Shares as of the Date of Exercise of this Warrant.

A. “Date of Exercise” means the date on which the Company shall have received (i) this Warrant (or any New Warrant, as applicable), with the Form of Election to Purchase attached hereto (or attached to such New Warrant) appropriately completed and duly signed, and (ii) payment of the Exercise Price for the number of Warrant Shares so indicated by the holder hereof to be purchased.

(c) This Warrant shall be exercisable, either in its entirety or, from time to time, for a portion of the number of Warrant Shares. If less than all of the Warrant Shares which may be purchased under this Warrant are exercised at any time, the Company shall issue or cause to be issued, at its expense, a New Warrant evidencing the right to purchase the remaining number of Warrant Shares for which no exercise has been evidenced by this Warrant.

(d) Prior to the exercise of this Warrant, the Holder shall not be entitled to any rights as a stockholder of the Company with respect to the Warrant Shares, including (without limitation) the right to vote such shares, receive dividends or other distributions thereon or be notified of stockholder meetings (except as otherwise set forth in Section 7(f) herein).

(e) If by the tenth business day after a Date of Exercise the Company fails to deliver the required number of Warrant Shares in the manner required pursuant to Section 3(b), then the Holder will have the right to rescind such exercise.

4. Payment of Taxes. The Company will pay any documentary stamp taxes attributable to the issuance of Warrant Shares upon the exercise of this Warrant; provided, however, that the Company shall not be required to pay any tax which may be payable in respect of any transfer involved in the registration of any certificates for Warrant Shares or Warrants in a name other than that of the Holder. The Holder shall be responsible for all other tax liability that may arise as a result of holding or transferring this Warrant or receiving Warrant Shares upon exercise hereof.

5. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or destroyed, the Company shall issue or cause to be issued in exchange and substitution for and upon cancellation hereof, or in lieu of and substitution for this Warrant, a New Warrant, but only upon receipt of evidence reasonably satisfactory to the Company of such loss, theft or destruction and indemnity, if requested, satisfactory to it. Applicants for a New Warrant under such circumstances shall also comply with such other reasonable regulations and procedures and pay such other reasonable charges as the Company may prescribe.

6. Reservation of Warrant Shares. The Company covenants that it will at all times reserve and keep available out of the aggregate of its authorized but unissued Common Stock, solely for the purpose of enabling it to issue Warrant Shares upon exercise of this Warrant as herein provided, the number of Warrant Shares which are then issuable and deliverable upon the exercise of this entire Warrant, free from preemptive rights or any other actual contingent purchase rights of persons other than the Holder. The Company covenants that all Warrant Shares that shall be so issuable and deliverable shall, upon issuance and the payment of the applicable Exercise Price in accordance with the terms hereof, be duly authorized, validly issued and fully paid and nonassessable.

7. Certain Adjustments. The Exercise Price and number of Warrant Shares issuable upon exercise of this Warrant are subject to adjustment from time to time as set forth in this Section 7. Upon each such adjustment of the Exercise Price pursuant to this Section 7, the Holder shall thereafter prior to the Expiration Date be entitled to purchase, at the Exercise Price resulting from such adjustment, the number of Warrant Shares obtained by multiplying the Exercise Price in effect immediately prior to such adjustment by the number of Warrant Shares issuable upon exercise of this Warrant immediately prior to such adjustment and dividing the product thereof by the Exercise Price resulting from such adjustment.

(a) If the Company, at any time while this Warrant is outstanding, (i) shall pay a stock dividend (except scheduled dividends paid on outstanding preferred stock which contain a stated dividend rate) or otherwise make a distribution or distributions on shares of its Common Stock payable in shares of Common Stock, (ii) subdivide outstanding shares of Common Stock into a larger number of shares, or (iii) combine outstanding shares of Common Stock into a smaller number of shares, the Exercise Price shall be multiplied by a fraction of which the numerator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding before such event and the denominator shall be the number of shares of Common Stock (excluding treasury shares, if any) outstanding after such event. Any adjustment made pursuant to this Section shall become effective immediately after the record date for the determination of stockholders entitled to receive such dividend or distribution and shall become effective immediately after the effective date in the case of a subdivision or combination, and shall apply to successive subdivisions and combinations.

(b) In case of any reclassification of the Common Stock, any consolidation or merger of the Company with or into another person, the sale or transfer of all or substantially all of the assets of the Company or any compulsory share exchange pursuant to which the Common Stock is converted into other securities, cash or property, then the Holder shall have the right thereafter to exercise this Warrant only into the shares of stock and other securities and property receivable upon or deemed to be held by holders of Common Stock following such reclassification, consolidation, merger, sale, transfer or share exchange, and the Holder shall be entitled upon such event