Exhibit 10.6

SECOND AMENDMENT TO EXCLUSIVE LICENSE AGREEMENT UC Agreement Control No. 2006-04-0085

This Second Amendment to Exclusive License Agreement (“Second Amendment”), dated as of

, 2006, is made by and among The Regents of the University of

California, a California corporation (“The Regents”), Medivation, Inc , a Delaware corporation (“Medivation”), and Medivation Prostate Therapeutics, Inc , a Delaware corporation and subsidiary of Medivation (“MPT”)

WHEREAS, The Regents, Medivation and MPT are parties to an Exclusive License Agreement, dated as of August 12, 2005 (the “Exclusive License Agreement”);

WHEREAS, Medivation has been supporting research in Dr Michael E Jung’s laboratory at UCLA under a Sponsored Research Agreement with an Effective Date of August 12, 2005 (the “Sponsored Research Agreement”);

WHEREAS, an invention has been developed at UCLA in the performance of the Sponsored Research Agreement, which is disclosed in UC Case No 2006-537 entitled “New Jhiohydantoin Androgen Receptor Antagonists for Treatment of Prostate Cancer” by Michael E Tung and Dongwon Yoo, employees of The Regents, Charles L Sawyers, an employee of Howard Hughes Medical Institute (“HHMI”) and a member of the faculty of the University of California, Los Angeles, and Chris Tran, an employee of HHMI;

WHERE AS, the Sponsored Research Agreement grants Medivation the first right to negotiate for a license to inventions made by The Regents in the performance of the Sponsored Research Agreement, and Medivation has exercised its right and wishes to obtain an exclusive license to the invention noted in the preceding WHEREAS clause;

WHEREAS, Medivation as the parent corporation of MPT will benefit directly from the agreements made her ein; and

WHEREAS, the parties mutually intend to enter into this Second Amendment to amend the terms of the Exclusive License Agreement, as specified below

THEREFORE, the parties hereby agree as follows:

1.1 “Regents’ Patent Rights” means The Regents interest in the claims of the United States patents and patent applications, corresponding foreign patents and patent applications (requested under Paragraph 7 3 herein), and any reissues, extensions, substitutions, continuations, divisions, and continuation-in-part applications (but only those claims in the continuation-in-part applications that are entirely supported in the specification and entitled to the priority date of the parent application) based

U.C. AGREEMENT CONTROL NUMBER

2006 04-0085 REVC

on the patent applications listed in Appendix A (UC Case Nos. 2004-129, 2005-438, 2006-260 and 2006-537)

The Regents, Medivation and MPT have executed this Amendment in duplicate originals by their

authorized officers on the dates written below:

APPENDIX A (Second Amendment)

REGENTS’ PATENT RIGHTS

UC Case No. 2004-129

PCT Patent Application No, US05/05529 “Methods and Materials for Assessing Prostate Cancer Therapies and Compounds filed February 23, 2005, based on US Provisional Patent Application No,, 60/547,101 filed Februaiy 24, 2004 The inventors are Michael E Jung, Samedy Ouk, Charlie D Chen and Derek Welsbie, employees of The Regents, and Charles L Sawyer s, an employee of the Howar d Hughes Medical Institute (“HHMI”) and a member of the faculty of The Regents ,

UC Case No. 2005-438

US Provisional Patent Application No. 60/680,8.35 “Novel Androgen Receptor Inhibitors with Minimal Agonistic Activities ,” filed May 13, 2005 The inventors are Michael E Jung, Samedy Ouk, Charlie D. Chen and Derek Welsbie, employees of The Regents, and Charles L Sawyers, an employee of the Howard Hughes Medical Institute (“HHMI”) and a member of the faculty of The Regents. This application, together with the patent application pertaining to UC Case No 2004-129, cover the compounds identified as RD1 through RD138, inclusive, on Exhibit A attached to the First Amendment

PCT Patent Application No. PCT/US06/11417 (also includes UC Case Nos. 2006-260 & 2006- 537) titled “Diarylthiohydantoin Compounds” was filed March 29, 2006 The inventors are Michael E . Jung, Samedy Ouk, Charlie D Chen, Der ek Welsbie and Dongwon Yoo, employees of The Regents, and Charles L Sawyers, an employee of Howard Hughes Medical Institute (“HHMI”) and a member of the faculty of the University of California, Los Angeles, and John Wongvipat and Chris Tran, employees of HHMI

UC Case No. 2006-260

US Provisional Patent Application No. 60/750,351 filed December 15, 2005 and US Provisional

Patent Application No. 60/756,552 filed January 6, 2006, both titled “Selected

Diarylthiohydantoin Compounds,” filed January 6, 2006 (both were subsequently rolled into PCT Patent Application No PCT/US06/11417), The inventors are Michael E Jung, Samedy Ouk and Charlie D Chen, employees of The Regents, and Charles L, Sawyers, an employee of the Howard Hughes Medical Institute (“HHMI”) and a member of the faculty of The Regents, and John Wongvipat and Chris Tran, employees of HHMI This application will cover only the following diarylthiohydantoin compounds developed in the laboratory of Michael E Jung, the structures of which are set forth on Exhibit A attached hereto:

RD168

UC Case No. 2006-537

Body text;

Chris Tran, an employee of HHMI. This application coveis the following compounds: RD162’, RD1627’, RD169 and RD170 (analogues of earlier compounds RD162 and RD131)