BETHESDA, Md., April 14 /PRNewswire-FirstCall/ -- Micromet, Inc. (Nasdaq: MITI), a biopharmaceutical company developing novel antibodies for the treatment of cancer, inflammation and autoimmune diseases, today presented at the Annual Meeting of the American Association for Cancer Research (AACR) in San Diego, CA, preclinical data of two new human BiTE(R) antibodies targeting CD33 and MCSP, for the treatment of acute myelogenous leukaemia (AML) and melanoma (1). BiTE antibodies are designed to direct the body's cytotoxic, or cell-destroying, T cells against tumor cells, and represent a new therapeutic approach to cancer therapy.
Generation of human anti-CD33 and anti-MCSP BiTE antibodies used a novel human BiTE antibody platform that is cross-reactive with non-human primates. In cell-based assays, CD33-specific and MCSP-specific BiTE antibodies were equally potent in eliminating tumor cells expressing the respective target antigens. While CD33 is present and well accessible on many normal blood cells, MCSP is barely accessible on normal cells, but is exposed and highly expressed on melanoma cells. Consistent with the accessibility of the respective target antigen, the CD33-specific BiTE antibody showed in macaques a dose-dependent depletion of CD33-expressing blood cells, whereas the MCSP-specific BiTE antibody did not show any activity, even at very high doses.
"We are very encouraged by the first in vivo results of these two new BiTE antibodies that continue to expand our novel BiTE antibody pipeline," comments Patrick Baeuerle, chief scientific officer of Micromet. "The data indicate highly target-specific activities of the two BiTE antibodies in primates, and suggest appropriate therapeutic windows for elimination of target cells in vivo."
About BiTE Antibodies
BiTE(R) antibodies are designed to direct the body's cytotoxic, or cell- destroying, T cells against tumor cells, and represent a new therapeutic approach to cancer therapy. BiTE antibodies have been shown to induce an immunological synapse between a T cell and a tumor cell in the same manner as observed during physiological T cell attacks. These cytolytic synapses enable the delivery of cytotoxic proteins from T cells into tumor cells, ultimately inducing a self-destruction process in the tumor cell referred to as apoptosis, or programmed cell death. In the presence of BiTE antibodies, T cells have been demonstrated to serially eliminate tumor cells, which explains the activity of BiTE antibodies at very low concentrations and at very low ratios of T cells to target cells. Through the process of killing cancer cells, T cells proliferate, which leads to an increased number of T cells at the site of attack.
Several antibodies in Micromet's product pipeline are BiTE antibodies and have been generated based on Micromet's proprietary BiTE antibody platform. The most advanced BiTE antibody is MT103 (MEDI-538), targeting CD19, and has provided proof-of-concept in an ongoing phase 1 clinical study in patients with advanced non-Hodgkin's lymphoma. MT110, which is targeting EpCAM (CD326) and is the first BiTE antibody with potential applications in the treatment of solid tumors, has completed preclinical development. Two additional BiTE antibodies, targeting CEA and MCSP, are in preclinical development.
About Micromet, Inc. (www.micromet-inc.com)
Micromet, Inc. is a biopharmaceutical company developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases. Three of its antibodies are currently in clinical trials, while the remainder of the product pipeline is in preclinical development. The BiTE(R) antibody MT103 is in a phase 2 clinical trial for the treatment of patients with acute lymphoblastic leukemia and in a phase 1 clinical trial for the treatment of patients with non-Hodgkin's lymphoma. BiTE antibodies represent a new class of antibodies that activate a patient's own cytotoxic T cells, considered the most powerful "killer cells" of the human immune system, to eliminate cancer cells. Micromet is developing MT103 in collaboration with MedImmune, Inc., a subsidiary of AstraZeneca plc. The second clinical stage antibody is adecatumumab, also known as MT201, a human monoclonal antibody which targets epithelial cell adhesion molecule (EpCAM)-expressing solid tumors. Micromet is developing adecatumumab in collaboration with Merck Serono in a phase 1b clinical trial evaluating adecatumumab in combination with docetaxel for the treatment of patients with metastatic breast cancer. The third clinical stage antibody, MT293 is licensed to TRACON Pharmaceuticals, Inc. and is being developed in a phase 1 clinical trial for the treatment of patients with cancer. In addition, Micromet has established a collaboration with Nycomed for the development and commercialization of MT203, a human antibody neutralizing the activity of granulocyte/macrophage colony stimulating factor (GM-CSF), which has potential applications in the treatment of various inflammatory and autoimmune diseases, such as rheumatoid arthritis, psoriasis, or multiple sclerosis.
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SOURCE Micromet, Inc.