[ * ] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS
BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES AND EXCHANGE COMMISSION PURSUANT TO
RULE 24B-2 OF THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED.
EXHIBIT 10.23
AMENDMENT
AMENDMENT dated December 15, 1997 (this “Amendment”), to the Amended and Restated Research, Development and
Marketing Collaboration Agreement between Onyx Pharmaceuticals, Inc., a California corporation (“Onyx”) and Warner-
Lambert Company, a Delaware corporation (“Warner”), which Amended and Restated Agreement (the “Agreement”) was
executed during July 1997.
W I T N E S S E T H:
WHEREAS, Onyx and Warner desire, among other things to modify the field of their cell cycle control collaboration under
the Agreement, extend the term of the Agreement and modify their mutual rights under the Agreement to Japan,
NOW, THEREFORE, the parties hereby agree as follows:
1. Definitions. (a) Capitalized terms used but not defined in this Amendment will have the meanings ascribed thereto in
the Agreement.
(b) The following definitions are hereby added to Article 1 of the Agreement:
2. Field. The definition of “Field” found in Article 1 of the Agreement is hereby amended by deleting the third and all
later paragraphs thereof in their entirety and replacing the same by the following:
1.
“Generation 1 Collaboration Compounds” shall mean Collaboration Compounds that are initially identified under the
Collaboration as having activity against any of the following targets: [*] .
“Generation 2 Collaboration Compounds” shall mean Collaboration Compounds that are initially identified under the
Collaboration as having activity against any targets in the Field other than those set forth in the definition of Generation 1
Collaboration Compounds.
Field
3. Term of Research Collaboration. Section 2.3 of the Agreement is hereby deleted in its