Document:

<PAGE>

                                                                   Exhibit 10.29
                                                                   -------------

                               AMENDMENT NO. 11
                   TO SHAREHOLDERS' AGREEMENT OF KIRIN-AMGEN

     AMENDMENT NO. 11 (this "Amendment") made effective as of March 20, 2000
(the "Effective Date") to the Shareholders' Agreement of Kirin-Amgen dated May
11, 1984 (as amended, the "Shareholders' Agreement") among Kirin Brewery Co.,
Ltd., a Japanese corporation with principal offices located at 10-1, Shinkawa
2-chome, Chuo-ku, Tokyo, 104, Japan ("Kirin"), Amgen Inc., a Delaware
corporation with principal offices located at One Amgen Center Drive, Thousand
Oaks, California 91320 ("Amgen") and Kirin-Amgen, Inc., a Delaware corporation
with principal offices located at c/o Amgen Europe AG, Grabenhof, 6010 Kirens,
Switzerland ("Kirin-Amgen").

                                   RECITALS

     WHEREAS, Kirin, Amgen and Kirin-Amgen have entered into the following
agreements (collectively referred to as the "NM321 Agreements") regarding a
novel growth factor that has erythropoiesis stimulating activity ("NM321" as
further defined in the NM321 Agreements):

          "Amendment No. 10 to Shareholder's Agreement of Kirin-Amgen" effective
March 1, 1996 by and among Kirin, Amgen and Kirin-Amgen ("Amendment No. 10");

          "NM321 Technology Transfer Agreement" effective March 1, 1996 by and
among Kirin, Amgen and Kirin-Amgen ("Technology Transfer Agreement");

          "Research, Development and Technology Disclosure Agreement: NM321"
effective March 1, 1996 by and among Kirin, Amgen and Kirin-Amgen ("Research
Development Agreement");

          "NM321 License Agreement" effective March 1, 1996 by and between
Kirin-Amgen and Kirin ("Kirin License Agreement"); and

          "NM321 License Agreement" effective March 1, 1996 by and between
Kirin-Amgen and Amgen ("Amgen License Agreement").

     WHEREAS, during the time period from January 1, 1997 to December 31, 1999,
Amgen conducted certain clinical trials and other development-related activities
related to the development of NM321 Products outside the United States which
development activities were not covered by the NM321 Agreements and which
activities were not paid for by Kirin-Amgen ("Amgen 1997-1999 Ex-US NM321
Development Activities").

     WHEREAS, the Amgen 1997-1999 Ex-US NM321 Development Activities have
resulted in a significant amount of information and proprietary data whether
tangible or intangible, including any and all data, pre-clinical and clinical
results, techniques, discoveries, inventions, ideas, processes, know-how,
patents, inventor's certificates, trade secrets and other proprietary
information and any physical, chemical or biological material (including cell
lines) and any replication of any part of such material (the "Amgen 1997-1999
Ex-US NM321 Data") to which Kirin-Amgen does not have rights under the NM321
Agreements.

          WHEREAS, Kirin, Amgen and Kirin-Amgen have now determined that the
Amgen 1997-1999 Ex-US NM321 Data is important to Kirin-Amgen's NESP development
activities and
<PAGE>

it is in the best interest of Kirin-Amgen to obtain access to the Data for use
in connection with the development, manufacture, use or sale of NM321 Products
in the Kirin Core Territories.

     WHEREAS, from January 1, 2000 through the end of NESP development activity,
Amgen intends to continue to conduct Amgen Ex-US NM321 Development Activities,
which activities are likely to result in additional Amgen Ex-US NM321 Data
("Amgen 2000 Ex-US NM321 Data", "Amgen 2001 Ex-US NM321 Data", etc.)
(collectively "Future Amgen Ex-US NM321 Data").

     WHEREAS, Kirin, Amgen and Kirin-Amgen believe that it is in the best
interest of Kirin-Amgen to have the option prior to each calendar year to
acquire access to the Amgen Ex-US NM321 Data to be generated during that coming
year for use in connection with the development, manufacture, use or sale of
NM321 Products in the Kirin Core Territories.

     WHEREAS, Kirin plans to conduct certain development activities related to
NM321 outside of Japan ("Kirin Ex-Japan NM321 Development Activities"), and the
parties have determined that such activities may result in proprietary data
("Kirin Ex-Japan NM321 Data") which could be beneficial to the partnership.

     WHEREAS, Kirin, Amgen and Kirin-Amgen have determined that it is in the
best interest of Kirin-Amgen to obtain access to the Kirin Ex-Japan NM321 Data
for use in connection with the development, manufacture, use or sale of NM321
Products world-wide.

     WHEREAS, the parties entered into a Binding Term Sheet by and among Kirin,
Amgen and Kirin-Amgen effective as of March 20, 2000 (the "Binding Term Sheet")
containing the material terms of this Agreement, and agreeing to enter into a
"Definitive Agreement" as defined in the Binding Term Sheet, and the parties now
wish this to be the Definitive Agreement referenced in the Binding Term Sheet.

     NOW, THEREFORE, in consideration of the mutual covenants expressed herein
and other good and valuable consideration, the parties agree as follows:

1.   AMGEN EX-US NM321 DATA
     ----------------------

     1.01 Transfer of Data: Amgen 1997-1999 Ex-US NM321 Data. It is agreed that
          --------------------------------------------------
Amgen will grant to Kirin-Amgen, perpetually and irrevocably, an exclusive
license (within the Kirin Core Territory) to the Amgen 1997-1999 Ex-US NM321
Data for use in connection with the development, manufacture, use or sale of
NM321 Products in the Kirin Core Territory as of the Effective Date hereof.
Amgen retains all rights to such Data outside the Kirin Core Territory. Upon
such transfer, Kirin-Amgen's interest in the Amgen 1997-1999 Ex-US NM321 Data
shall be considered Research Project Technology for purposes of the NM321
Agreements; as such, the license granted to Kirin from Kirin-Amgen in the Kirin
License Agreement will include rights to the Amgen 1997-1999 Ex-US NM321 Data
for use in the Kirin Core Territory.

                                       2
<PAGE>

     1.02 Consideration to Amgen: Amgen 1997-1999 Ex-US NM321 Data. In exchange
          --------------------------------------------------------
for the license to Amgen 1997-1999 Ex-US NM321 Data as provided in Section 1.01,
Kirin-Amgen will pay Amgen Seventy Five Million US Dollars (USD $75,000,000) as
follows:

     (a)  Thirty Seven Million Five Hundred Thousand US Dollars (USD
$37,500,000), which was paid to Amgen in March 2000 upon execution of the
Binding Term Sheet.

     (b)  Thirty Seven Million Five Hundred Thousand US Dollars (USD
$37,500,000) upon receipt by Amgen of all necessary regulatory approvals for,
and the completion of, the first commercial sale of an NM321 Product in any
country within the Amgen Additional Territory. Amgen will invoice Kirin-Amgen
for this amount upon completion of such first commercial sale, and Kirin-Amgen
shall pay that amount in full within 30 days of receipt of such invoice.

     1.03 Option to Purchase Future Amgen Ex-US NM321 Data. Prior to each
          ------------------------------------------------
calendar year, Kirin-Amgen shall have the option to purchase an exclusive
license (within the Kirin Core Territory) to the Amgen Ex-US NM321 Data for that
coming year for use in connection with the development, manufacture, use or sale
of NM321 Products in the Kirin Core Territory. Following the disclosure of
protocols by Amgen to Kirin, and the discussion and the overall consensus on the
study plan and cost by Amgen and Kirin, by August 31 of each calendar year,
Amgen shall provide Kirin-Amgen with a summary description of the Ex-US NM321
Development Activities to be undertaken in the coming year. Kirin-Amgen shall
then have until September 30 of that year to exercise its option to acquire (at
the price determined in Section 1.04 below) a license to the Amgen Ex-US NM321
Data for that coming year. If Kirin-Amgen exercises the option, Kirin-Amgen will
obtain a license to all Data for the coming year; the option does not include
the right to acquire a license to less than all the Data for a particular year.
Upon Kirin-Amgen's exercise of its option and payment of the determined price,
Kirin-Amgen will acquire, perpetually and irrevocably, an exclusive license
(within the Kirin Core Territory) to that year's Amgen Ex-US NM321 Data for use
in connection with the development, manufacture, use or sale of NM321 Products
in the Kirin Core Territory. Amgen would retain all rights to such Data outside
the Kirin Core Territory.

Example:  For year 2001, Amgen must present Kirin-Amgen with a summary
          description of its 2001 Ex-US NM321 Development Activities by August
          31, 2000. Kirin Amgen must then elect by September 30, 2000 whether or
          not to exercise its option to acquire a license to the Amgen 2001
          Ex-US NM321 Data. Upon exercise of such option, Kirin-Amgen shall
          acquire the exclusive license (within the Kirin Core Territory) to the
          Amgen 2001 Ex-US NM321 Data for use in connection with the
          development, manufacture, use or sale of NM321 Products in the Kirin
          Core Territory.
          Note: with respect to Amgen 2000 Ex-US NM321 Data only, Amgen shall
          provide a description of its 2000 Ex-US Development Activities to
          Kirin-Amgen and Kirin-Amgen shall have thirty days from that time to
          make its election.

Upon Kirin-Amgen's exercise of its right to acquire a license to any Data
pursuant to this Section 1.03, Kirin-Amgen's interest in any licensed Data shall
be considered Research Project Technology for purposes of the NM321 Agreements;
as such, the license granted to Kirin from Kirin-Amgen in the Kirin License
Agreement will include rights to all such licensed Data. Regardless of
Kirin-Amgen's exercise of its option with respect to any Future Amgen Ex-US

                                       3
<PAGE>

NM321 Data, Amgen retains sole authority and discretion over all aspects of the
Amgen Ex-US NM321 Development Activities.

     1.04 Consideration to Amgen: Future NM321 Data. In exchange for the license
          -----------------------------------------
to use any Future Amgen Ex-US NM321 Data as provided in Section 1.03,
Kirin-Amgen will pay to Amgen a price for the license to use the Data (the
"Option Price"). The parties agree to negotiate in good faith the appropriate
Option Price, and that such Option Price will reflect the fair market value of
the use of the licensed data . The Option Price for the license to a particular
year's Data shall be payable quarterly in four equal installments, each payable
on or about the first day of each quarter. Both Parties agree to review the
Option Price of the previous year and discuss in good faith whether to make
reasonable and appropriate adjustments to the Option Price. If the Amgen Ex-US
NM321 Development Activities for a particular year change substantially after
the parties have agreed upon an Option Price for the license to the Data
corresponding to that year's Development Activities, then, upon request by
either Kirin or Amgen, the parties agree to discuss in good faith whether to
make reasonable and appropriate adjustments to the Option Price.

2.   KIRIN EX-JAPAN NM321 DATA
     -------------------------

     2.01 Transfer of Data. It is agreed that Kirin will transfer and assign to
          ----------------
Kirin-Amgen, perpetually and irrevocably, all of its right, title and interest
in and to the Kirin Ex-Japan NM321 Data as of the Effective Date hereof. Upon
such transfer, all Kirin Ex-Japan NM321 Data shall be considered Research
Project Technology for purposed of the NM321 Agreements; as such, the license
granted to Amgen from Kirin-Amgen in the Amgen License Agreement will include
rights to all Kirin Ex-Japan NM321 Data.

     2.02 Consideration to Kirin. In exchange for the transfer of the Kirin
          ----------------------
Ex-Japan NM321 Data by Kirin in Section 2.01, Kirin shall invoice Kirin-Amgen
for the transfer price as the work is performed, with such transfer price
determined at the rates and the manner set forth in Section 3.05 of the Research
Development Agreement, as if the Kirin Ex-Japan NM321 Development Activities had
been funded by Kirin-Amgen. For costs already incurred by Kirin from January 1,
2000 to the present, if any, Kirin shall invoice Kirin-Amgen promptly, and
Kirin-Amgen shall pay the transfer price within 30 days of receipt of the
invoice.

3.   ADJUSTMENT TO ROYALTIES

     3.01 Royalties from Amgen.
          --------------------

     (a)  Adjustment to Royalty Payable on Sales in Amgen Additional Territory.
          --------------------------------------------------------------------
The royalty payable from Amgen to Kirin-Amgen for sales of NM321 Products in the
Amgen Additional Territory shall be revised as follows (subject to adjustments
provided in Article 4 of the Amgen License Agreement, as amended):

          In exchange for the license to Amgen in the Amgen Additional
          Territory, Amgen will pay to Kirin-Amgen a royalty equal to three
          percent (3%) of the Sales Value of NM321 Products sold by or on

                                       4
<PAGE>

          behalf of Amgen in the Amgen Additional Territory. Amgen's royalty
          obligation to Kirin-Amgen in the Amgen Additional Territory shall be
          reduced to two percent (2%) only with respect to the aggregate
          cumulative Sales Value of NM321 Product sold by or on behalf of Amgen
          in the Amgen Additional Territory above five hundred million U.S.
          dollars (US$ 500,000,000).

     (b)  No Other Adjustment. The royalties payable by Amgen to Kirin- Amgen
          -------------------
for sales of NM321 Products in all other Amgen Territories are not altered by
this Amendment.

     3.02 Rovalties from Kirin. The royalties payable by Kirin to Kirin-Amgen
          --------------------
for sales of NM321 Products in Kirin Territories are not altered by this
Amendment.

4.   CONSISTENCY WITH SHAREHOLDERS' AGREEMENT;
     RATIFICATION; DEFINED TERMS

     4.01 Consistency. The rights and obligations of the parties with respect to
          -----------
this Amendment No. 11 as an expansion of Kirin-Amgen's business opportunities
are otherwise consistent with the Shareholders' Agreement.

     4.02 Ratification. All terms and conditions of the Shareholders' Agreement
          ------------
as amended by this Amendment No. 11 are hereby ratified and confirmed in all
respects.

     4.03 Definitions. All capitalized terms not otherwise defined herein shall
          -----------
have the meaning assigned to them in the relevant NM321 Agreements.

5.   MISCELLANEOUS

     5.01 Further Instruments. Each party hereto agrees to perform any and all
          -------------------
further acts and execute and deliver any and all further instruments which may
be reasonable or necessary to carry out the provisions of this Amendment No. 11
(including without limitation, any and all reasonable or necessary amendments to
the NM321 Agreements) and to carry out this further business purpose of Kirin-
Amgen.

     5.02 Governing Law and Severability. This Amendment shall be construed
          ------------------------------
under and in accordance with, and governed in all respects by, the law of the
State of California (without giving effect to principles of conflicts of law).
If any provision of this Amendment is deemed invalid or unenforceable by a court
of competent jurisdiction, such invalidity or enforceability shall not affect or
limit the validity or enforceability of any other provision hereof.
<PAGE>

     5.03 Counterparts. This Amendment may be executed in two or more
          ------------
counterparts, each of which shall be deemed an original and all of which
together constitute one instrument.

     5.04 Effect on Binding Term Sheet. Upon execution of this Amendment, this
          ----------------------------
Amendment shall replace and supersede the Binding Term Sheet in its entirety.

IN WITNESS WHEREOF, the undersigned have caused this Amendment to be executed by
their duly authorized representatives in the manner legally binding upon them.

                         Kirin Brewery Co., Ltd.

                             /s/ Koichiro Aramaki
                         By: Koichiro Aramaki Ph.D.
                         Title: President, Pharmaceutical Div.

                         June 30, 2000
                         Date

                         Amgen Inc.

                            /s/ Craig Brooks
                         By: Craig Brooks
                         Title: Vice President,
                                Asia Pacific/Latin America

                         June 30, 2000
                         Date

                         Kirin-Amgen, Inc.

                         /s/ Katsuhiko Asano
                          Katsuhiko Asano, Ph.D.
                         Chairman

                         June 30, 2000
                         Date

                                       6<PAGE>

                                                                   Exhibit 10.31
                                                                   -------------

                                AMENDMENT N0. 1
                                ---------------
                                      TO
                                      --
                            KIRIN-AMGEN, INC./AMGEN
                            -----------------------
                       G-CSF EUROPEAN LICENSE AGREEMENT
                       --------------------------------

         THIS AMENDMENT N0. 1 ("Amendment No. 1") TO THAT CERTAIN KIRIN-AMGEN,
INC./AMGEN G-CSF EUROPEAN LICENSE AGREEMENT ("License Agreement"), is made and
entered into this 1st day of June, 1987, by and between AMGEN INC., a Delaware
corporation ("Amgen"), and KIRIN-AMGEN, INC., a California corporation
("Corporation").

                                R E C I T A L S
                                - - - - - - - -

         A.  Amgen and Corporation have previously executed that certain License
Agreement regarding G-CSF.

         B.  The parties desire to incorporate certain definitional changes into
the License Agreement.

         NOW, THEREFORE, it is agreed as follows:

1.       Article I at pages 2-3 of the License Agreement is hereby amended as
follows:

                                 "ARTICLE   I

                                  DEFINITIONS
                                  -----------

         1.01  Incorporation by Reference. Unless otherwise defined
               --------------------------
         herein, capitalized terms shall have the meanings specified
         in that certain Company Shareholders' Agreement dated May 11,
         1984, as amended ("Shareholders' Agreement"), and in that
         certain Research, Development, Technology Disclosure and
         License Agreement: PPO effective as of July 1, 1985 ("PPO
         Agreement").

         1.04  G-CSF Products. "G-CSF Products" shall mean any
               --------------
         product, method or system for human pharmaceutical use which
         contains G-CSF as its single primary element.

         1.05  G-CSF Technology. "G-CSF Technology" shall mean all G-
               ----------------
         CSF technical information whether tangible or intangible,
         including any and all data, pre-clinical and clinical
         results, techniques, discoveries, inventions, ideas,
         processes, know-how, patents, inventor's certificates, trade
         secrets and other proprietary information, and any physical,
         chemical or biological material (including cell lines) and
         any replication of any part of any such material.
<PAGE>

         1.08  G-CSF. "G-CSF" shall mean a glycosylated or
               -----
         nonglycosylated molecule consisting of the linear array of
         amino acids attached as Exhibit "A" hereto or any variation
         thereof consisting of additions, deletions or substitutions
         of up to ten amino acids, and shall include the definition of
         PPO as set forth in the PPO Agreement."

2.       Except to the extent as provided herein, the provisions of
the License Agreement, as amended, are hereby ratified and confirmed
in all respects.

         IN WITNESS WHEREOF, the undersigned have caused this Amendment No. 1 to
be executed as of the first day written above .

                                   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"

                                      -2-
<PAGE>

                                     G-CSF
                                 ------------

A              Amino acids [23-30]  Lys   Ile   Gln   Gly   Asp  Gly   Ala   Ala

               mRNA                 AAG AUC CAG GGC GAU GGC GCA GCG

               Probes [24-23 mers]  TTC TAC GTC CCT CTA CCT GGT CG

B -12  -10
ELU TRP HIS SER ALA LEU TRP THR VAL GLN GLU   ALA THR PRO LEU
CIG TGG CAC AGI GIA CIC TGG ACR GIG CAG GAA GCC ACC CCC   CIG

10
ALY PRO ALA SER SER LEU PRO GLN SER PHE LEU LEU LYS CYS LEU
GGC CCT GCC AGC TCC CTG CCC CAG AGC TTC CTG CTC AAG TGC TTA

20            30              phe
ALU GLN VAL ARG LYS ILE GLN GLY ASP GLY ALA ALA LEU GLN GLN
GAG CAA GTG AGG AAG ATC CAG GGC GAT GGC GCA GCG CTC CAG GAG

     gly
LYS LEU CYS ALA THR TYR LYS LEU CYS HIS PRO GLU GLU LEU VAL
AAG CTG TGT GCC ACC TAC AAG CTG TGT CAC CCC GAG GAG CTG GTG

50                         60
LEU LEU GLY HIS SER LEU GLY ILE PRO TRP ALA PRO LEU SER SER
CTG CTC GGA CAC TCT CTG GGC ATC CCC TGG GCT CCC CTG AGC AGC

         70
CYS PRO SER GLN ALA LEU GLN LEU ALA GLY CYS LEU SER GLN LEU
TGC CCC AGC CAG GCC CTG CAG CTG GCA GGC TGC TTG AGC CAA CTC

80                     90
HIS SER GLY LEU PHE LEU TYR GLN GLY LEU LEU GLN ALA LEU GLN
CAT AGC GGC CTT TTC CTC TAC CAG GGG CTC CTG CAG GCC CTG GAA

                  100
GLY ILE SER PRO GLU LEU GLY PRO THR LEU ASP THR LEU GLN LEU
GGG ATC TCC CCC GAG TTG GGT CCC ACC TTG GAC ACA CTG CAG CTG

110                                  120
ASP VAL ALA ASP PHE ALA THR   THR ILE TRP GLN GLN MET GLU GLU
GAC GTC GCC GAC TTT GCC ACC ACC ATC TGG CAG CAG ATG GAA GAA

               130
LEU GLY MET ALA PRO ALA LEU GLN PRO THR GLN GLY ALA MET PRO
CTG GGA ATG GCC CCT GCC CTG CAG CCC ACC CAG GGT GCC ATG CCG

  140                            150
ALA PHE ALA SER ALA PHE GLN ARG ARG ALA GLY GLY VAL LEU VAL
GCC TTC GCC TCT GCT TTC CAG CGC CGG GCA GGA GGG GTC CTG GTT

                       160
ALA SER HIS LEU GLN SER PHE LEU GLU VAL SER TYR ARG VAL LEU
GCC TCC CAT CTG CAG AGC TTC CTG GAG GTG TCG TAC CGC GTT CTA

  170                174
ARG HIS LEU ALA GLN PRO OP
CGC CAC CTT GCC CAG CCC TGA  GCCAAGCCCTCCCCATCCCATGTATTTATCT

CTATTTAATATTTATGTCTATTTAAGCCTCATATTTAAAGACAGGGAAGAGCAGAACGG

AGCCCCAGGCCTCTGTGTCCTTCCCTGCATTTCTGAGTTTCATTCTCCTGCCTGTAGCA

GTGAGAAAAAGCTCCTGTCCTCCCATCCCCTGGACTGGGAGGTAGATAGGTAAATACCA

AGTATTTATTACTATGACTGCTCCCCAGCCCTGGCTCTGCAATGGGCACTGGGATGAGC

CGCTGTGAGCCCCTGGTCCTGAGGGTCCCCACCTGGGACCCTTGAGAGTATCAGGTCTC

CCACGTGGGAGACAAGAAATCCCTGTTTAATATTTAAACAGCAGTGTTCCCCATCTGGG

TCCTTGCACCCCTCACTCTGGCCTCAGCCGACTGCACAGCGGCCCCTGCATCCCCTTGG

CTGTGAGGCCCCTGGACAAGCAGAGGTGGCCAGAGCTGGGAGGCATGGCCCTGGGGTCC

CACGAATTTGCTGGGGAATCTCGTTTTTCTTCTTAAGACTTTTGGGACATGGTTTGACT

CCCGAACATCACCGACGTGTCTCCTGTTTTTCTGGGTGGCCTCGGGACACCTGCCCTGC

CCCCACGAGGGTCAGGACTGTGACTCTTTTTAGGGCTAGGCAGGTGCCTGGACATTTGC

CTTGCTGGACGGGGACTGGGGATGTGGGAGGGAGCAGACAGGAGGAATCATGTCAGGCC

TGTGTGTGAAAGGAAGCTCCACTGTCACCCTCCACCTCTTCACCCCCCACTCACCAGTG

TCCCCTCCACTGTCACATTGTAACTGAACTTCAGGATAATAAAGTGTTTGCCTCCAA

                                  EXHIBIT "A"

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00020-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00020-of-00352.parquet"}]]