Exhibit 4.1



                                 AMENDMENT NO. 1

                                     TO THE

                                RIGHTS AGREEMENT

                          DATED AS OF DECEMBER 13, 2000

                                 BY AND BETWEEN

                         SPECTRUM PHARMACEUTICALS, INC.

                                       AND

                         U.S. STOCK TRANSFER CORPORATION

      On December 13, 2000, the Board of Directors of Spectrum Pharmaceuticals,
Inc., a Delaware corporation (the "Company") authorized and declared a dividend
distribution of one Right (as defined in the Rights Agreement) for each share of
its Common Stock, each Right initially representing the right to purchase
one-hundredth of a share of Series B Junior Participating Preferred Stock of the
Company, upon the terms set forth in a Rights Agreement dated as of December 13,
2000 by and between U.S. Stock Transfer Corporation (the "Rights Agent") and the
Company (the "Rights Agreement")

      The Company recently entered into a Preferred Stock and Warrant Purchase
Agreement dated April 29, 2003 (the "Purchase Agreement"), pursuant to which the
Company issued and sold shares of its Series D 8% Cumulative Convertible Voting
Preferred Stock (the "Series D Preferred Stock") and Series D Common Stock
Purchase Warrants (the "Warrants"). Pursuant to the terms of the Certificate of
Designation of the Series D Preferred Stock (the "Certificate of Designations"),
each holder of the Series D Preferred Stock has the right to receive, on the
Distribution Date (as defined in the Rights Agreement), without further action
by the Board, such number of Rights (as defined in the Rights Agreement) equal
to the number of Rights such holder would have held if, immediately prior to the
Distribution Date, all of the shares of Series D Preferred Stock had been
converted into shares of Common Stock at the then current Conversion Value (as
defined in the Certificate of Designations). Pursuant to the terms of the
Warrants, each holder of a Warrant has the right to receive, after the
Distribution Date, upon exercise of the Warrant, such number of Rights equal to
the number of Rights such holder would have held if, immediately prior to the
Distribution Date, the portion of this Warrant being exercised at such time had
been exercised and the Warrant Shares issuable upon such exercise were
outstanding immediately prior to the Distribution Date.

      Therefore, in order to give effect to the above terms of the Series D
Preferred Stock and the Warrants, the Company and U.S. Stock Transfer
Corporation hereby agreed to amend the Rights Agreement as follows:

      1.    Amend Section 1(a) of the Rights Agreement to add the following
            separate paragraph at the end of the section:

            "Also, notwithstanding the foregoing, each of the Purchasers listed
on Schedule 1 to the Preferred Stock and Warrant Purchase Agreement dated April
29, 2003 (the "Purchase Agreement"), by and among the Company and the Purchasers
thereto, shall not be deemed to be an "Acquiring Person," by virtue of such
Purchaser acquiring Beneficial Ownership of shares of Common Stock pursuant to
the terms of the Purchase Agreement, the Certificate of Designations (the
"Certificate of Designations") of the Company's Series D 8% Cumulative
Convertible Voting Preferred Stock (the "Series D Preferred Stock"), the
Warrants (as defined in the Purchase Agreement) or the Placement Agent Warrants
issued or issuable to SCO Financial Group LLC, and/or its designees, pursuant to
that certain financial advisory agreement between the Company and SCO Financial
Group LLC, dated February 1, 2003 (the Warrants and the Placement Agent Warrants
hereinafter referred to as the "Warrant" if singular, or "Warrants" if plural).
However, this exception to the definition of "Acquiring Person" shall not affect
the determination of whether the Purchasers or any of them or SCO Financial
Group LLC, shall be an "Acquiring Person" as the result of any other acquisition
of Beneficial Ownership of shares of Common Stock."

      2.    Add subsection (d) to Section 3 of the Rights Agreement to read in
            its entirety as follows:

            "(d) Notwithstanding any of the foregoing, each record holder of
shares of Series D Preferred Stock has the right to receive, on the Distribution
Date, such number of Rights equal to the number of Rights such holder would have
held if, immediately prior to the Distribution Date, all of the shares of Series
D Preferred Stock had been converted into shares of Common Stock at the then
current Conversion Value (as defined in the Certificate of Designations). As
soon as practicable after the Distribution Date (but in any case no later than 5
business days following the Distribution Date), the Rights Agent will send by
first-class, insured, postage prepaid mail, to each record holder of the Series
D Preferred Stock as of the Close of Business on the Distribution Date, one or
more Rights Certificates evidencing the Rights so held. No further Rights shall
attach or be issuable in respect of any shares of Common Stock issued thereafter
upon conversion of any shares of Series D Preferred Stock. In addition,
notwithstanding any of the foregoing, any holder of a Warrant who exercises any
portion of such Warrant after a Distribution Date shall receive, upon exercise
of such Warrant, a number of Rights equal to the number of Rights such holder
would have held in respect of the Warrant Shares (as defined in the Warrant)
issuable upon such exercise if the portion of the Warrant being exercised had
been exercised immediately prior to the Distribution Date. As soon as
practicable after such exercise (but in any case no later than 5 business days
following such exercise), the Rights Agent will send by first-class, insured,
postage prepaid mail, to the record holder of such Warrant Shares, one or more
Rights Certificates evidencing the Rights so held. In an event that an
adjustment in the number of Rights per share of Common Stock has been made
pursuant to Section 11(p) hereof, the Company shall make the necessary and
appropriate rounding adjustments (in accordance with Section 14(a) hereof) so
that Rights Certificates representing only whole numbers of Rights are
distributed and cash is paid in lieu of any fractional Rights.

                            [SIGNATURE PAGE FOLLOWS]

      IN WITNESS WHEREOF, the Company and the Rights Agent have caused this
amendment to be executed this 23rd day of July, 2003.

                          Spectrum Pharmaceuticals, Inc.


                          By:  /s/ Rajesh C. Shrotriya
                               ------------------------

                          Name:Rajesh C. Shrotriya, M.D.
                               -------------------------

                          Title:Chairman, Chief Executive Officer and President
                                -----------------------------------------------

                          U.S. Stock Transfer Corporation

                          By:  /s/ Richard C. Brown
                               ---------------------

                          Name:Richard C. Brown
                               ----------------

                          Title:Vice President
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