Ipilimumab Plus Chemotherapy is Associated with Prolonged Survival and Increased Disease Control Rates in Patients with Advanced Melanoma

PRINCETON, N.J. (Map) - PRINCETON, N.J., June 1 /PRNewswire-FirstCall/ -- Medarex, Inc. (Nasdaq: MEDX) today announced updated long-term follow-up and overall survival (OS) results from a Phase 2 clinical study (MDX010-08) of 3 mg/kg of ipilimumab in combination with dacarbazine (DTIC) where 11.4%, or 4 of 35 patients, were still alive at or greater than 4 years of follow-up. This included 1 patient that experienced a complete response (4.7 years), 1 patient that experienced a partial response (4.2 years), 1 patient with stable disease (4.6 years) and 1 patient with RECIST defined progressive disease (4.4 years). The median OS for patients treated with ipilimumab in combination with DTIC was 15 months in this study. These results compare favorably with data in medical literature, in which median OS ranges from 6 to 9 months for patients with treated or previously untreated advanced melanoma treated with standard chemotherapy. These findings were presented at the Annual Meeting of the American Society of Clinical Oncology (ASCO), being held in Chicago, IL May 30-June 3, 2008. (Abstract # 9022)

"The long-term survival data suggests that ipilimumab in combination with DTIC may have long-lasting effects," said Geoffrey M. Nichol, MBChB, Senior Vice President of Product Development at Medarex. "With a median survival of approximately 15 months in the patients treated with 3 mg/kg of ipilimumab in combination with DTIC in this Phase 2 study, we look forward with interest to the outcome of the ongoing Phase 3 study being performed by our collaborator Bristol-Myers Squibb Company, comparing 10 mg/kg of ipilimumab in combination with DTIC versus DTIC alone in previously-untreated patients with advanced melanoma."

In the Phase 2 trial (MDX010-08), 72 chemotherapy-naive patients with advanced melanoma were treated with 3 mg/kg of ipilimumab monthly for four months and were randomized to receive either ipilimumab in combination with DTIC (n=35) or ipilimumab alone (n=37). Patients originally treated in the MDX010-08 study were subsequently enrolled into study MDX010-028 to determine long-term follow-up data and OS. The disease control rate (proportion of patients with complete responses, partial responses or stable disease) for patients treated with ipilimumab in combination with DTIC was 37.1%, or 13 of 35 patients, with 2 complete responses, 3 partial responses and 8 patients with stable disease. Two of 37 patients, or 5.4%, treated with 3 mg/kg of ipilimumab alone experienced partial responses, which were ongoing more than 4 years and 4.2 years in duration, respectively. The disease control rate in the ipilimumab alone treatment arm was 21.6%, or 8 of the 37 patients, with median OS of 12 months.

Ipilimumab is being developed through a joint partnership between Bristol-Myers Squibb and Medarex. Based on preclinical and clinical studies showing that antibody blockade of CTLA-4 plays an important role in sustaining an active immune response to fight cancer, the companies are pursuing a broad clinical development program with ipilimumab. More than 2,000 patients have been treated in clinical trials with ipilimumab as a monotherapy or in combination with other agents. Patients in the ongoing Phase 3 study (BMS study CA184-024) are randomized to receive induction therapy with 10 mg/kg of ipilimumab in combination with DTIC or placebo. Eligible patients are permitted maintenance dosing with ipilimumab or placebo after the induction phase has been completed.

For further information about ipilimumab clinical trials, please visit www.clinicaltrials.gov.

About Ipilimumab

Ipilimumab is a fully human antibody that binds to CTLA-4 (cytotoxic T lymphocyte-associated antigen 4), a molecule on T-cells that plays a critical role in regulating natural immune responses. The absence or presence of CTLA-4 can augment or suppress the immune system's T-cell response in fighting disease. Ipilimumab is designed to block the activity of CTLA-4, thereby sustaining an active immune response in its attack on cancer cells.

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. More than 40 of these therapeutic product candidates derived from Medarex technology are in human clinical testing or have had INDs submitted for such trials, with seven of the most advanced product candidates currently in Phase 3 clinical trials or the subject of regulatory applications for marketing authorization. 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 Web site at www.medarex.com.

Medarex Statement on Cautionary Factors

Except for the historical information presented herein, matters discussed herein may constitute forward-looking statements, as defined in the Private Securities Litigation Reform Act of 1995, that are subject to certain risks and uncertainties that could cause actual results to differ materially from any future results, performance or achievements expressed or implied by such statements. Statements that are not historical facts, including statements preceded by, followed by, or that include the words "suggests"; "potential"; or "may"; or similar statements are forward-looking statements. Medarex disclaims, however, any intent or obligation to update these forward-looking statements. These risks and uncertainties include whether the actual results in the clinical studies described above will differ materially from results in future use of ipilimumab, whether development of ipilimumab will be successful, whether the clinical studies described in this release will support the filing of a BLA with the FDA, or whether, if a BLA is filed with the FDA, it will be filed in the timeframe developed by the parties or will receive regulatory approval, as well as risks detailed from time to time in Medarex's public disclosure filings with the U.S. Securities and Exchange Commission (SEC), including its Annual Report on Form 10-K for the fiscal year ended December 31, 2007 and its quarterly reports on Form 10-Q. There can be no assurance that such development efforts will succeed or that other developed products will receive required regulatory clearance or that, even if such regulatory clearance were received, such products would ultimately achieve commercial success. Copies of Medarex's public disclosure filings are available from its investor relations department.

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