UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G/A
                    Under the Securities Exchange Act of 1934
				Amendment No. 1


                            Spectrum Pharmaceuticals
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                    84763A108
                                 (CUSIP Number)

                                 September 12, 2006

             (Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

[x] Rule 13d-1(b)

[ ] Rule 13d-1(c)

[ ] Rule 13d-1(d)

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter the
disclosures provided in a prior cover page.


The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).




                               CUSIP No.  84763A108


       1.    Names of Reporting Persons.
             I.R.S. Identification Nos. of above persons (entities only).

             OrbiMed Advisors LLC

       2.    Check the Appropriate Box if a Member Of a Group (See Instructions)

             [ ] (a)
             [ ] (b)

       3.    SEC Use Only

       4.    Citizenship or Place of Organization

             Delaware

       5.    Sole Voting Power: 0
Number of
Shares           6.  Shared Voting Power: 777,795
Beneficially
Owned by         7.  Sole Dispositive Power:  0
Each Reporting
Person With      8.  Shared Dispositive Power: 777,795

       9.    Aggregate Amount Beneficially Owned by Each Reporting Person
             777,795

       10.   Check if the Aggregate Amount in Row (9) Excludes Certain Shares
             (See Instructions)

       11.   Percent of Class Represented by Amount in Row (9) 3.06%

       12.   Type of Reporting Person (See Instructions) IA






                               CUSIP No.  84763A108


       1.    Names of Reporting Persons.
             I.R.S. Identification Nos. of above persons (entities only).

             OrbiMed Capital LLC

       2.    Check the Appropriate Box if a Member of a Group (See Instructions)

             [ ] (a)
             [ ] (b)

       3.    SEC Use Only

       4.    Citizenship or Place of Organization

             Delaware

       5.    Sole Voting Power: 0
Number of
Shares           6.  Shared Voting Power: 458,193
Beneficially
Owned by         7.  Sole Dispositive Power: 0
Each Reporting
Person With      8.  Shared Dispositive Power:  458,193

       9.    Aggregate Amount Beneficially Owned by Each Reporting Person
             458,193

       10.   Check if the Aggregate Amount in Row (9) Excludes Certain Shares
             (See Instructions)

       11.   Percent of Class Represented by Amount in Row (9) 1.80%

       12.   Type of Reporting Person (See Instructions) IA




                               CUSIP No.  84763A108


       1.    Names of Reporting Persons.
             I.R.S. Identification Nos. of above persons (entities only).

             Samuel D. Isaly

       2.    Check the Appropriate Box if a Member of a Group (See Instructions)

             [ ] (a)
             [ ] (b)

       3.    SEC Use Only

       4.    Citizenship or Place of Organization

             United States

       5.    Sole Voting Power: 0
Number of
Shares           6.  Shared Voting Power: 1,235,988
Beneficially
Owned by         7.  Sole Dispositive Power: 0
Each Reporting
Person With      8.  Shared Dispositive Power: 1,235,988

       9.    Aggregate Amount Beneficially Owned by Each Reporting Person:
             1,235,988

       10.   Check if the Aggregate Amount in Row (9) Excludes Certain Shares
             (See Instructions)

       11.   Percent of Class Represented by Amount in Row (9) 4.86%**

       12.   Type of Reporting Person (See Instructions) HC




Item 1. (a)  Issuer: Spectrum Pharmaceuticals

             1.      Address:
                     157 TECHNOLOGY DR
		     IRVINE CA 92618



Item 2. (a)  Name of Person Filing:
             OrbiMed Advisors LLC
             OrbiMed Capital LLC
             Samuel D. Isaly

        (b)  Address of Principal Business Offices:

             767 Third Avenue, 30th Floor
             New York, New York 10017

        (c)  Citizenship:
             Please refer to Item 4 on each cover sheet for each filing person

        (d)  Title of Class of Securities
             Common stock

        (e)  CUSIP Number:  84763A108

Item 3. OrbiMed Advisors LLC and OrbiMed Capital LLC are investment advisors in
accordance with ss.240.13d-1(b)(1)(ii)(E). Samuel D. Isaly is a control person
in accordance with ss.240.13d-1(b)(1)(ii)(G).

Item 4.  Ownership

         Please see Items 5 - 9 and 11 for each cover sheet for each filing
separately

Item 5.  Ownership of Five Percent or Less of a Class

         Reporting persons are holding 4.86% of the securities on behalf of
         other persons who have the right to receive or the power to direct
         the receipt of dividends from, or proceeds from sale of, such
	 securities. No one such other person's interest in the securities
	 whose ownership is reported here relates to more than five percent
         of the class.

         OrbiMed Advisors LLC and OrbiMed Capital LLC hold shares on
         behalf of Caduceus Capital Master Fund Limited (87,662 shares and
         294,531 warrants), Caduceus Capital II, L.P. (45,500 shares
         and 153,000 warrants), UBS Eucalyptus Fund, LLC (74,300 shares and
         250,000 warrants), PW Eucalyptus Fund, Ltd. (7,500 shares
         and 25,000 warrants), HFR SHC Aggressive Fund (17,500 shares and
	 58,500 warrants), Knightsbridge Post Venture IV L.P. (10,545 shares
	 and 35,500 warrants), Knightsbridge Integrated Holdings, V, LP
         (11,700 shares and 39,500 warrants),Knightsbridge Netherlands II,
         LP (3,000 shares and 10,000 warrants), Knightsbridge
	 Integrated Holdings IV Post Venture, LP (4,500 shares and
         15,000 warrants), Knightsbridge Post Venture III, LP (3,000 shares
         and 9,750 warrants), Knightsbridge Netherlands I LP (2,800 shares
         and 9,400 warrants), Knightsbridge Netherlands III LP
         (2,900 shares and 9,650 warrants), Knightsbridge Integrated
         Holdings II Limited (3,600 shares and 12,250 warrants),
         Knightsbridge Venture Completion 2005 LP (1,100 shares and 3,750
	 warrants), and Knightsbridge Venture Capital VI LP (3,000 shares and
         10,150 warrants), Knightsbridge Venture Capital IV LP (2,900 shares
         and 9,600 warrants), and Knightsbridge Venture Capital III LP
         (2,100 shares and 6,800 warrants).



Item 6.  Ownership of More than Five Percent on Behalf of Another Person.

	 Not Applicable









Item 7.  Identification and Classification of the Subsidiary Which Acquired the
Security  Being Reported on By the Parent Holding Company

         Not Applicable

Item 8.  Identification and Classification of Members of the Group

         Not Applicable


Item 9.  Notice of Dissolution of Group

         Not Applicable

Item 10. Certification

         By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired and held in the ordinary
course of business and were not acquired and are not held for the purpose of or
with the effect of changing or influencing the control of the issuer of the
securities and were not acquired and are not held in connection with or as a
participant in any transaction having that purpose or effect.





                                    SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Date: September 19, 2006
                                       OrbiMed Advisors LLC

                                       By: /s/ Samuel D. Isaly
                                       --------------------------
                                       Name:  Samuel D. Isaly
                                       Title: President

                                       OrbiMed Capital LLC

                                       By: /s/ Samuel D. Isaly
                                       --------------------------
                                       Name:  Samuel D. Isaly
                                       Title: Managing Member


                                       By: /s/ Samuel D. Isaly
                                       --------------------------
                                       Name:  Samuel D. Isaly


			JOINT FILING AGREEMENT

The undersigned hereby agree that the Statement on this Schedule 13G/A, dated
September 19,2006, (the "Schedule 13G/A"), with respect to the Common Stock,
par value $.001 per share, of Spectrum Pharmaceuticals is filed on behalf of
each of us pursuant to and in accordance with the provisions of Rule 13d-1(k)
under the Securities and Exchange Act of 1934, as amended, and that this
Agreement shall be included as an Exhibit to this Schedule 13G/A. Each of the
undersigned agrees to be responsible for the timely filing of the Schedule
13G/A, and for the completeness and accuracy of the information concerning
itself contained therein. This Agreement may be executed in any number of
counterparts, all of which taken together shall constitute one and the same
instrument.

        IN WITNESS WHEREOF, the undersigned have executed this Agreement as of
the 19th day of Sepember, 2006.


                                          OrbiMed Advisors LLC

                                          By: /s/ Samuel D. Isaly
                                          ---------------------------
                                          Name:  Samuel D. Isaly
                                          Title: Managing Member


                                          OrbiMed Capital LLC

                                          By: /s/ Samuel D. Isaly
                                          ----------------------------
                                          Name:  Samuel D. Isaly
                                          Title: Managing Member


                                          By: /s/ Samuel D. Isaly
                                          ----------------------------
                                          Name:  Samuel D. Isaly






				Statement of Control Person


The Statement on this Schedule 13G/A dated September 19, 2006 with respect to
the common stock, $.001 par value per share, of Spectrum Pharmaceuticals is
filed by Samuel D. Isaly in accordance with the provisions of Rule 13d-1(b)
and Rule 13d-1(k),respectively, as control person (HC) of OrbiMed Advisors LLC
and OrbiMed Capital LLC.

OrbiMed Advisors LLC and OrbiMed Capital LLC file this statement on Schedule
13G/A in accordance with the provisions of Rule 13d-1(b) and Rule 13d-1(k),
respectively, as investment advisors (IA).