PRINCETON, N.J., June 7 /PRNewswire-FirstCall/ -- Medarex, Inc. (Nasdaq: MEDX) today announced that in a Phase II clinical study the overall response rate in metastatic melanoma patients treated with MDX-010 in combination with dacarbazine was 17.1%, or 6 of 35 patients, with the median duration of complete and partial responses ongoing at 167 days. One patient experienced an ongoing complete response of ten months duration, and five patients experienced partial responses with the longest ongoing response of over ten months duration. In addition, four patients with stable disease were observed. In a similar metastatic melanoma patient population, a recent study conducted by a third party showed that the response rate for dacarbazine treatment alone was 6.8% in 385 patients with a median duration of responses of 128 days.(1) The Medarex study was presented by Evan M. Hersh, M.D., of the Arizona Cancer Center, in the melanoma discussion session at the 40th Annual Meeting of the American Society of Clinical Oncology (ASCO), June 5-8, 2004, in New Orleans, LA. (Abstract #7511) In addition to the MDX-010 and dacarbazine treatment arm, 2 of 37 patients, or 5.4%, treated with 3 mg/kg of MDX-010 alone experienced partial responses, which are ongoing at over five months and seven months in duration, respectively. Also, four patients experienced stable disease, the longest of which is currently approaching one year in duration. In the Phase II trial, patients were treated with 3mg/kg of MDX-010 monthly for four months and were randomized to receive either MDX-010 alone or MDX-010 in combination with dacarbazine. Nine of 72 patients, or 12.5%, in the study reported Grade III or IV serious adverse events. The most common events that were consistent with an immune-based mechanism of action due to MDX-010 mediated CTLA-4 blockade, now termed Autoimmune Breakthrough Events (ABEs), were diarrhea, rash and increased liver enzymes. With exception to one colectomy case due to treatment-resistant colitis complicated by a bacterial infection (combination treatment), one fatal outcome suggestive of dacarbazine-mediated acute liver toxicity (combination treatment), and one fatal outcome suggestive of a pulmonary embolism or acute cardiovascular event (monotherapy treatment), most ABEs resolved with treatment. "We are pleased with the complete and partial response data thus far," said Donald L. Drakeman, President and CEO of Medarex. "We expect to closely monitor and review the duration of patient responses as we consider the further clinical development plans for this program." In the second half of 2004, Medarex expects to initiate a pivotal study with a separate MDX-010 treatment combination based on a peptide vaccine in metastatic melanoma, pending approval of a Special Protocol Assessment (SPA) application that was filed with the FDA. In addition, MDX-010 is being tested in a Phase II chemotherapy combination clinical trial for prostate cancer and is also being studied as a monotherapy in a Phase II clinical trial for breast cancer and a Phase I clinical trial for HIV. About MDX-010 and Melanoma MDX-010 is a fully human antibody against human CTLA-4, a molecule on T cells that is believed to be responsible for suppressing the immune response. Studies in mice have demonstrated that an antibody against CTLA-4 has the potential to strengthen the adaptive immune response against certain tumors, leading to the reduction of and, in some cases, the elimination of well- established tumors. In preclinical research, MDX-010 has been shown to enhance immune responses and prevent tumor growth. In a separate Phase II clinical study, 21% of 14 metastatic melanoma patients treated with a high dose of MDX-010 in combination with a gp100 peptide vaccine experienced complete or partial responses. The two patients with complete responses and the one patient with a partial response still remain cancer-free for over twenty months. Data from this clinical study suggested that the development of durable complete and partial responses in patients with extensive metastatic disease was associated with the induction of some drug-related ABEs seen at higher doses; however, no unmanageable toxicities were observed. According to the American Cancer Society, cancer of the skin is the most common of all cancers. Melanoma accounts for about 4% of skin cancer cases, but it causes about 79% of skin cancer deaths. The American Cancer Society estimates that in 2004 there will be about 55,100 new cases of melanoma in the United States, and about 7,910 people will die of this disease. About Medarex Medarex is a biopharmaceutical company focused on the discovery and development of therapeutics to treat life-threatening and debilitating diseases. Medarex's UltiMAb Human Antibody Development System(R) is a unique combination of human antibody technologies that Medarex believes enables the rapid creation and development of fully human antibodies to a wide range of potential disease targets for therapeutic antibody products, including products for the treatment of cancer, inflammation, autoimmune and infectious diseases. Medarex's product pipeline is based on a variety of therapeutic antibody products developed through the use of its UltiMAb(TM) technology. Medarex creates and develops fully human antibodies for itself and others, offering a full range of antibody related capabilities, including pre-clinical and clinical development supported by cGMP manufacturing services. For more information about Medarex, visit its website at http://www.medarex.com. Except for the historical information presented herein, matters discussed herein may constitute forward-looking statements 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 "potential"; "believe"; "anticipate"; "intend"; "plan"; "expect"; "estimate"; "could"; "may"; or similar statements are forward-looking statements. Medarex disclaims, however, any intent or obligation to update these forward-looking statements. Risks and uncertainties include risks associated with product discovery and development, uncertainties related to the outcome of clinical trials, slower than expected rates of patient recruitment, unforeseen safety issues resulting from the administration of antibody products in patients, uncertainties associated with the collaborative process, uncertainties related to product manufacturing 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, 2003 and subsequent Quarterly Reports on Form 10-Q. There can be no assurance that such development efforts will succeed, that such 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. Medarex(R), the Medarex logo, and UltiMAb Human Antibody Development System(R) are registered trademarks of Medarex, Inc. UltiMAbTM is a trademark of Medarex, Inc. All rights are reserved. (1) FDA Oncologic Drugs advisory Committee Briefing Material, dated May 3, 2004. http://www.fda.gov/ohrms/dockets/ac/04/briefing/4037b1.htm
SOURCE Medarex, Inc.