Medarex Announces Presentations at Annual Meeting of the American Society of Clinical Oncology

- Updated Survival and Biomarker Data for Ipilimumab to be Presented -

PRINCETON, N.J., April 29 /PRNewswire-FirstCall/ — Medarex, Inc. (Nasdaq: MEDX) announced today that the following clinical abstracts for ipilimumab in melanoma and prostate cancer, as well as for an anti-PD-1 antibody for cancer treatment, have been selected to be the subject of presentations at the Annual Meeting of the American Society of Clinical Oncology, being held May 29-June 2, 2009 in Orlando:

Survival, Response, Safety and Biomarker Data of Ipilimumab in Melanoma

• “Association of baseline and on-study tumor biopsy markers with clinical activity in patients (pts) with advanced melanoma treated with ipilimumab” (Abstract #9008, Developmental Therapeutics: Immunotherapy Session) O. Hamid – Oral presentation from 1:00 p.m. to 4:15 p.m. local time on Saturday, May 30, 2009.

• “Increased humoral and cellular immunity in patients (pts) with advanced melanoma treated with ipilimumab” (Abstract #3031, Developmental Therapeutics: Immunotherapy Session) S. Parker – General poster from 8:00 a.m. to 12:00 p.m. local time on Saturday, May 30, 2009.

• “Effect of ipilimumab treatment on 18-month survival: update of patients with advanced melanoma treated with 10 mg/kg ipilimumab in three Phase II clinical trials” (Abstract #9033, Melanoma Session) S. O’Day – Poster discussion from 8:00 a.m. to 12:00 p.m. local time on Sunday, May 31, 2009.

• “Immunologic impact of anti-CTLA-4 therapy” (Abstract #3019, Development Therapeutics: Immunotherapy Session) P. Sharma – Poster discussion from 2:00 p.m. to 6:00 p.m. local time on Sunday, May 31, 2009.

• “Association of peripheral blood lymphocyte count (ALC) and clinical activity in patients (pts) with advanced melanoma treated with ipilimumab” (Abstract #3020, Developmental Therapeutics: Immunotherapy Session) D. Berman – Poster discussion from 2:00 p.m. to 6:00 p.m. local time on Sunday, May 31, 2009.

• “Phase 2 trial of extended dose anti-CTLA-4 antibody ipilimumab (formerly known as MDX-010) with a multipeptide vaccine for resected stages IIIC and IV melanoma” (Abstract #9023, Melanoma Session) J. Weber – Poster discussion from 8:00 a.m. to 12:00 p.m. local time on Sunday, May 31, 2009.

• “Evaluation of the effect of systemic corticosteroids for the treatment of immune-related adverse events (irAEs) on the development or maintenance of ipilimumab clinical activity” (Abstract #9037, Melanoma Session) A. Amin – General poster from 8:00 a.m. to 12:00 p.m. local time on Monday, June 1, 2009.

• “Association between immune-related adverse events (irAEs) and disease control or overall survival in patients (pts) with advanced melanoma treated with 10 mg/kg ipilimumab in three Phase 2 clinical trials” (Abstract #9034, Melanoma Session) J. Lutzky – General poster from 8:00 a.m. to 12:00 p.m. local time on Monday, June 1, 2009.

• “Efficacy of ipilimumab 10 mg/kg in advanced melanoma patients (pts) with good and poor prognostic factors” (Abstract #9036, Melanoma Session) J. Wolchok – General poster from 8:00 a.m. to 12:00 p.m. local time on Monday, June 1, 2009.

• “Long-term survival in patients (pts) with advanced melanoma treated with ipilimumab with or without dacarbazine” (Abstract #9038, Melanoma Session) E. Hersh – General poster from 8:00 a.m. to 12:00 p.m. local time on Monday, June 1, 2009.

• “Effect of ipilimumab at 10 mg/kg on disease control in patients (pts) with M1c-stage melanoma in relation to baseline lactate dehydrogenase (LDH) levels” (Abstract #9041, Melanoma Session) M. Smylie – General poster from 8:00 a.m. to 12:00 p.m. local time on Monday, June 1, 2009.

Response and Safety Data of Ipilimumab in Prostate

• “Initial Phase 2 experience of ipilimumab (IPI) alone and in combination with radiotherapy (XRT) in patients with metastatic castration resistant prostate cancer (mCRPC)” (Abstract #5138, Genitourinary Cancer – Prostate Session) S. Slovin – General poster from 2:00 p.m. to 6:00 p.m. local time on Sunday, May 31, 2009.

• “Phase 1 trial of targeted therapy with PSA-TRICOM Vaccine (V) and ipilimumab (ipi) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC)” (Abstract #5144, Genitourinary Cancer Session) M. Mohebtash – General poster from 2:00 p.m. to 6:00 p.m. local time on Sunday, May 31, 2009.

Clinical Data of MDX-1106 in Cancer

• “Phase 2 experience with MDX-1106 (Ono-4538), an anti-PD-1 monoclonal antibody, in patients with selected refractory or relapsed malignancies” (Abstract #3018, Developmental Therapeutics: Immunotherapy Session) J. Brahmer – Poster discussion from 2:00 p.m. to 6:00 p.m. local time on Sunday, May 31, 2009.

More information about the ASCO Annual Meeting may be found at www.asco.org.

About Medarex

Medarex is a biopharmaceutical company focused on the discovery, development and potential commercialization of fully human antibody-based therapeutics to treat life-threatening and debilitating diseases, including cancer, inflammation, autoimmune disorders and infectious diseases. Medarex applies its UltiMAb(R) technology and product development and clinical manufacturing experience to generate, support and potentially commercialize a broad range of fully human antibody product candidates for itself and its partners. Over forty of these therapeutic product candidates derived from Medarex technology are in human clinical testing or have had INDs submitted for such trials, with the most advanced product candidates currently in Phase 3 clinical trials, the subject of regulatory applications for marketing authorization or approved for commercial sale. Medarex is committed to building value by developing a diverse pipeline of antibody products to address the world’s unmet healthcare needs. For more information about Medarex, visit its website at www.medarex.com.

Medarex(R), the Medarex logo and UltiMAb(R) are registered trademarks of Medarex, Inc. All rights are reserved.

SOURCE Medarex, Inc.