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                                                                   Exhibit 10.42
                                                                   -------------

                                AMENDMENT NO. 6
                                ---------------
                                      TO
                            SHAREHOLDERS' AGREEMENT
                            -----------------------
                                      OF
                               KIRIN-AMGEN, INC.
                               -----------------

          THIS AMENDMENT NO. 6 ("Amendment No. 6") TO THAT CERTAIN SHAREHOLDERS'
AGREEMENT, OF KIRIN-AMGEN, INC., dated May 11, 1984, as previously amended
("Shareholders' Agreement"), is made and entered into this 1st day of June,
1987, by and among KIRIN BREWERY, CO., LTD., a Japanese corporation ("Kirin"),
AMGEN INC., a Delaware corporation ("Amgen"), and KIRIN-AMGEN, INC., a
California corporation ("Corporation").

                                R E C I T A L S

          A.   Kirin and Amgen have previously entered into certain agreements
and understandings ("Prior Agreements") regarding G-CSF (having been previously
sometimes referred to as "PPO") and hereby acknowledge and reconfirm that on and
after July 1, 1986, Corporation had the obligation to fund all development costs
of the G-CSF Technology.

          B.   Kirin and Amgen have assigned and transferred to Corporation all
of their right, title and interest in and to the G-CSF (PPO) technology
effective as of and pursuant to certain transfer agreements dated July 1, 1986.

          C.   The parties have made certain business agreements regarding the
further development of G-CSF (PPO) and wish to formalize said agreements.

          NOW, THEREFORE, it is agreed as follows:

1.        The research and development performed by Amgen on behalf of
Corporation with respect to G-CSF (PPO) pursuant to the Prior Agreements, shall,
from the effective date of that certain Development Agreement between Amgen and
Amgen Clinical Partners, L.P., dated June 1, 1987, be conducted in connection
with uses of G-CSF other than in the Field of Activity as defined in the
Glossary attached thereto. Subject to Amgen's rights under that certain G-CSF
European License Agreement dated December 30, 1986, and Kirin's rights under
that certain G-CSF Japanese License Agreement dated June 1, 1987, Corporation
shall have all rights with respect to such research and development outside of
such Field of Activity (as defined in the Glossary attached to the Development
Agreement).
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2.   Except to the extent as provided herein, the provisions of the
     Shareholders' Agreement, as amended, are hereby ratified and confirmed in
     all respects:

          IN WITNESS WHEREOF, the undersigned have caused this Amendment No. 6
     to be executed as of the first day written above.


                                              KIRIN BREWERY CO., LTD., a
                                              Japanese corporation


                                              By /s/ Y. Yamamoto
                                                Yashushi Yamamoto,
                                                Senior Managing Director

                                                            "Kirin"


                                              AMGEN INC., a Delaware corporation


                                              By /s/ George B. Rathmann
                                                George B. Rathmann, President

                                                            "Amgen"


                                              KIRIN-AMGEN, INC., a California
                                              corporation


                                              By /s/ Y. Yamamoto
                                           Yashushi Yamamoto, Chairman

                                                            "Corporation"

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