Clinical study planned for relapsed / refractory acute myelogenous leukemia

PRINCETON, NJ, USA |  May 27, 2009 | Medarex, Inc. (Nasdaq: MEDX) announced today the allowance of an investigational new drug application (IND) filed with the U.S. Food & Drug Administration (FDA) for MDX-1338, for the treatment of patients with acute myelogenous leukemia (AML). MDX-1338 is a fully human antibody that targets CXCR4, a chemokine receptor found on the surface of many cancer cells, including certain leukemias, lymphomas and other cancers. Preclinical laboratory experiments have shown that MDX-1338 can block the growth of, and even directly kill, selected human tumor cells.

The Phase 1, open-label, multicenter, dose-escalation study of MDX-1338 as a monotherapy and in combination with chemotherapy is expected to enroll up to 34 patients with relapsed/ refractory AML. This trial is designed to establish and evaluate the safety, tolerability and maximum tolerated dose, as well as preliminary pharmacodynamics and efficacy of MDX-1338.

"We are pleased that MDX-1338 has progressed into the clinic, representing our eighth development candidate in oncology and further enhancing our focus on oncology/immunology therapeutic indications," said Howard H. Pien, Chairman and CEO of Medarex. "We believe that MDX-1338 could have potential activity in multiple cancers. Our first Phase 1 study will be conducted in AML and future studies are expected to target a variety of other leukemias and solid tumors and may involve monotherapy and combination therapy."

The American Cancer Society estimates that in 2008, approximately 13,290 patients in the United States will be diagnosed with AML.

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, 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 approved for commercial sale, the subject of regulatory applications for marketing authorization or in Phase 3 clinical trials. 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.

SOURCE Medarex, Inc.