Cougar Biotechnology Appoints Michael Richman to Board of Directors.

LOS ANGELES -- Cougar Biotechnology, Inc., a publicly held biotechnology company, today announced the appointment of Michael S. Richman to the Company's Board of Directors. Mr. Richman is currently the Executive Vice President and Chief Operating Officer of Macrogenics, Inc, a privately held biotechnology company engaged in the development of immune-based products including monoclonal antibodies to treat patients with cancer, autoimmune disorders, allergy, or infectious diseases and vaccines to prevent infections in healthy individuals.

Prior to Macrogenics, Mr. Richman held various positions at Medimmune from 1996 to 2002 including the position of Senior Vice President of Corporate Development and Administration. Mr. Richman also served in a variety of business development and intellectual property positions at Chiron from 1987 through 1996 including the position of Director of Corporate Business Development. Mr. Richman holds an M.S.B.A in International Business from San Francisco State University and a B.S. from the University of California at Davis.

"We are pleased to have an independent director of Michael's caliber join the Cougar Board of Directors at this important stage of the Company's development," said Dr. Arie Belldegrun, MD, FACS, Vice Chairman of the Board of Directors of Cougar Biotechnology. Alan H. Auerbach, Chief Executive Officer and President of Cougar Biotechnology, added, "Michael brings to Cougar an extensive background in biotechnology that includes valuable experience in operations, business development and intellectual property. We look forward to Michael making a significant contribution to the Board of Directors of the Company and to the future growth of Cougar."

About Cougar Biotechnology

Cougar Biotechnology, Inc. is a Los Angeles-based publicly held biotechnology company established to in-license and develop clinical stage drugs, with a specific focus on the field of oncology. Cougar's oncology portfolio includes CB7630, a targeted inhibitor of the 17-alpha hydroxylase/c17,20 lyase enzyme which is currently being tested in a Phase I clinical trial in prostate cancer; CB3304, an inhibitor of microtubule dynamics which is currently in a Phase I trial in hematological malignancies and CB1089, an analog of vitamin D which has been clinically tested in a number of solid tumor types.

Further information about Cougar Biotechnology can be found at www.cougarbiotechnology.com.

This press release contains forward-looking statements that involve risks and uncertainties that could cause Cougar's actual results and experiences to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are often, but not always, made through the use of words or phrases such as "anticipates," "expects," "plans," "believes," "intends," and similar words or phrases. These statements are based on current expectations, forecasts and assumptions that are subject to risks and uncertainties, which could cause actual outcomes and results to differ materially from these statements. Among other things, there can be no assurances that any of Cougar's development efforts relating to its product candidates will be successful. Other risks that may affect forward-looking information contained in this press release include the possibility of being unable to obtain regulatory approval of Cougar's product candidates, the risk that the results of clinical trials may not support Cougar's claims, Cougar's reliance on third-party researchers to develop its product candidates, and its lack of experience in developing and commercializing pharmaceutical products. Additional risks are described in the company's Current Report on Form 8-K filed with the Securities and Exchange Commission on April 7, 2006. Cougar assumes no obligation to update these statements, except as required by law.