EXHIBIT 10.21

                                 AMENDMENT No. 8

                                       to

                        THE DEVELOPMENT AND MANUFACTURING
                               SERVICES AGREEMENT

                              Dated 08 January 2004

                                     Between

                               LONZA BIOLOGICS PLC

                                       and

                          TRUBION PHARMACEUTICALS, INC.

                                                          CONFIDENTIAL TREATMENT



     THIS AMENDMENT No. 8 ("Eighth Amendment") is made the 5th day of October
2005

     BETWEEN

     LONZA BIOLOGICS PLC of 228 Bath Road, Slough, Berkshire SL1 4DX, England
(hereinafter referred to as "LB"), and

     TRUBION PHARMACEUTICALS, INC., of 2401 4th Avenue, Suite 1050, Seattle, WA
98121, USA (herein after referred to as the "Customer")

     WHEREAS

     A.   LB and the Customer entered into a development and manufacturing
          services agreement ("the Agreement") dated 08 January 2004, pursuant
          to which LB agreed to provide Services to the Customer, and,

     B.   The Customer now wishes LB to perform additional services under the
          Agreement, and,

     C.   LB is willing to perform such additional services on the terms set out
          in the Agreement, and

     D.   The parties wish to amend the Agreement in accordance with Clause 13.5
          thereto.

     NOW THEREFORE IT IS HEREBY AGREED as follows:

     1.0 STAGE 26 IN SCHEDULE 2 OF THE AGREEMENT SHALL BE DELETED IN ITS
ENTIRETY AND REPLACED WITH THE FOLLOWING:

     "STAGE 26 ***

     BACKGROUND

     ***

     26.1 OBJECTIVES

     ***

     26.2 ACTIVITIES

     ***

     26.3 DELIVERABLES

          26.3.1 A copy of the sampling plan prepared in activity 26.2.1.

                                                          CONFIDENTIAL TREATMENT



          26.3.2 Samples from the development study as agreed in activity 26.2.1
and 26.2.14

          26.3.3 A copy of the experimental data as prepared in activity 26.2.11

     26.4 TIMESCALE

     Stage 26 commenced upon signature of Amendment 6 dated 28th April 2005. It
is estimated that Stage 26 will be complete approximately *** from
commencement."

     2.0 TWO NEW STAGES, STAGES 29 AND 30, SHALL BE ADDED TO SCHEDULE 2 OF THE
AGREEMENT TO READ AS FOLLOWS:

     "STAGE 29 ***

     BACKGROUND

     ***

     29.1 OBJECTIVES

     ***

     29.2 ACTIVITIES

     ***

     29.3 DELIVERABLES

          29.3.1 A copy of the experimental data as prepared in activity
29.2.11.

     29.4 TIMESCALE

     Stage 29 commenced at Customer's request in June 2005.

     It is estimated that Stage 29 will be complete approximately *** from
commencement.

     STAGE 30 ***

     BACKGROUND

     ***

     30.1 OBJECTIVES

     ***

     30.2 ACTIVITIES

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                                       -2-



     ***

     30.3 DELIVERABLES

          30.3.1 A copy of the summary report of activities as prepared in
activity 30.2.7

     30.4 TIMESCALE

     Stage 30 commenced at Customer's request ***. It is estimated that Stage 30
will be complete approximately *** from commencement."

                                                          CONFIDENTIAL TREATMENT


                                       -3-



     SCHEDULE 3 TO THE AGREEMENT SHALL BE AMENDED TO INCLUDE PROVISION FOR
PAYMENT FOR THE ABOVE MENTIONED ADDITIONAL SERVICES, AS SET OUT BELOW HERETO.
INVOICES FOR THESE ADDITIONAL SERVICES SHALL BE ISSUED, AND CUSTOMER PAYMENTS
SHALL BE MADE, IN GB POUNDS STERLING:

     "1.  PRICE

     ***

     2.   PAYMENT

          FOR STAGE 26

          *** received upon commencement of Stage 26

          *** upon completion of Stage 26.

          FOR STAGE 30

          *** upon commencement of Stage 30.

          *** upon completion of Stage 30."

                                                          CONFIDENTIAL TREATMENT


                                       -4-



     SAVE AS HEREIN PROVIDED ALL OTHER TERMS AND CONDITIONS OF THE AGREEMENT
SHALL REMAIN IN FULL FORCE AND EFFECT.

     AS WITNESS the hands of the duly authorised representatives of the parties
hereto the day and year first above written.

Signed for and on behalf of
LONZA BIOLOGICS PLC                     /s/ Rene Imwinkleried
                                        ----------------------------------------
                                        Director
                                        TITLE

Signed for and on behalf of
TRUBION PHARMACEUTICALS, INC            /s/ Kendall M. Mohler
                                        ----------------------------------------
                                        Senior VP Research & Development
                                        TITLE

                                                          CONFIDENTIAL TREATMENT