EXHIBIT 10.51

[*]=CERTAIN INFORMATION ON THIS PAGE HAS BEEN OMITTED AND
FILED SEPARATELY WITH THE COMMISSION. CONFIDENTIAL TREATMENT
HAS BEEN REQUESTED WITH RESPECT TO THE OMITTED PORTIONS.

April 25, 2002

Mr. Brad Crawford
Amgen Inc.
One Amgen Center Drive
Thousand Oaks, CA 91320-1799

Re:Amendment No. 1 to Amgen/InterMune License and Commercialization
Agreement for Infergen

Dear Mr. Crawford:

Our signatures below approve this document as Amendment No. 1 ("Amendment") to
that certain License and Commercialization Agreement, dated as of June 15, 2001,
between Amgen Inc. ("Amgen") and InterMune, Inc. ("InterMune") (the
"Agreement"). Amgen and InterMune shall be collectively referenced herein as the
"Parties."

For good and valuable consideration, the receipt of which is hereby
acknowledged, the Parties hereby agree as follows:

1.The second sentence of Section 1.27 of the Agreement (definition of Licensed
Product) is hereby deleted in its entirety and amended and superseded as
follows:

"Licensed Products include but are not limited to Infergen and PEG-Infergen
Products."

2.The following shall be added to the last sentence of Section 3.3 of the
Agreement:

", and such PEG-Infergen Product shall be [*]"

3.The following shall be added to the last sentence of Section 5.2(b) of the
Agreement:

", and such PEG-Infergen Product shall be [*]"

4.The first sentence of Section 6.3(a) of the Agreement is hereby terminated in
its entirety and amended and superseded as follows:

        "InterMune shall pay to Amgen milestone payments as set forth in this
Section 6.3(a) within [*] after the first achievement of the corresponding
milestone for a PEG-Infergen Product that (i) is pegylated [*] and/or (ii) is
pegylated [*] (in either case, an "Amgen PEG-Infergen Product") that is [*] to
be [*]

5.The phrase [*] in Item 2 of the Milestone Events table in Section 6.3 (b) of
the Agreement shall be deleted and replaced with the phrase [*]

6.In consideration for Amgen extending the know-how license granted to InterMune
in Section 2.4 of the Agreement to further allow InterMune to use Amgen Know-How
for the sole purposes of [*] in the Territory and for its convenience, InterMune
proposed payment of [*]. Amgen accepted InterMune's proposal, and [*].
Accordingly,Section 6.5 of the Agreement is hereby terminated in its entirety
and amended and superseded as follows:

        "6.5 Term of Royalties.    Amgen's right to receive Royalties under
Section 6.4 shall expire, on a Licensed Product-by-Licensed Product basis, in
each country of the Territory upon the [*]. Notwithstanding the foregoing
sentence, Amgen shall have the right to receive from InterMune, and

1

--------------------------------------------------------------------------------

InterMune shall be obligated to pay to Amgen, Royalties for any PEG-Infergen
Product [*]; provided, however, that InterMune's obligation to pay Royalties for
any PEG-Infergen Product [*] shall [*] if and [*] as a [*] at [*] that is a [*]

7.This Amendment shall be deemed to amend terms of the Agreement pursuant to
Section 15.1 thereof and the Agreement, as amended and modified by this
Amendment, shall remain in full force and effect and shall constitute the
complete, final and exclusive understanding and agreement of the parties
respecting the subject hereof and thereof.

8.Whenever possible, each provision of this Amendment shall be interpreted in
such a manner as to be effective and valid under applicable law, but should any
provision of this Amendment be held to be prohibited or invalid under applicable
law, such provision shall be ineffective only to the extent of such prohibition
or invalidity, without invalidating the remainder of this Amendment.

9.This Amendment shall be governed by and interpreted in accordance with the
substantive laws of the State of California and the Parties hereby submit to the
jurisdiction of the California courts, both state and federal.

10.No amendment, modification or supplement of any provision of this Amendment
shall be valid or effective unless made in writing and signed by a duly
authorized officer of each Party.

11.This Amendment may be signed in any number of counterparts, each of which
shall be an original, with the same effect as though the signatures hereto and
thereto were on the same instrument.

12.This Amendment No. 1 to the Agreement is made effective as of April 25, 2002.

IN WITNESS THEREOF, the parties have executed this Amendment No. 1 to the
Agreement as of the date(s) set forth below.

INTERMUNE, INC.   AMGEN INC.
By:
/s/  STEPHEN N. ROSENFIELD      
 
By:
/s/  SCOTT J. FORAKER      
Print Name:    Stephen N. Rosenfield
 
Print Name:    Scott J. Foraker
Title:
Senior Vice President of Legal Affairs and General Counsel
 
Title:
VP Licensing Date: 4/24/02   Date: 4/24/02

2

--------------------------------------------------------------------------------