New Data Published in Immunobiology Describe Mode of Action of BiTE Antibody MT110

Study shows that very low amounts of Micromet's EpCAM-targeting BiTE antibody trigger the death of cancer cells 


BETHESDA, Md., Jan. 28  /PRNewswire-FirstCall/ -- Micromet, Inc. (NASDAQ: MITI), a biopharmaceutical company developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases, today announced publication of new data in the peer-reviewed journal Immunobiology describing in detail the mode of action of BiTE antibody MT110. MT110 is a T cell-engaging antibody that targets EpCAM, which is expressed with high frequency on most human adenocarcinoma.

Data from the new publication(1) demonstrate that when T cells are connected to cancer cells by MT110, they deliver two kinds of toxic proteins into cancer cells. One toxic protein, perforin, forms holes in the cancer cell's outer membrane. The second kind of protein, granzymes, is a family of proteolytic enzymes that triggers the self-destruction of the cancer cell, a process called programmed cell death or apoptosis. Very low amounts of MT110 were also found to increase the level of toxic proteins in T cells during cancer cell lysis, which is necessary for BiTE antibody-activated T cells to adopt a serial cancer cell-killing mode during which these toxic proteins are steadily consumed.

"Our new data explain the high anti-tumor activity of MT110 that we have seen in preclinical models, and that we have also observed with BiTE antibody blinatumomab in phase 1 and 2 clinical trials," commented Micromet's Chief Scientific Officer Dr. Patrick A. Baeuerle. "The mechanism of action of MT110 described in this study is expected to be identical for BiTE antibodies targeting other surface targets, and shows that this new class of antibody therapeutics has the potential to fully harness the power of T cells, the body's most potent immune cells, against malignant cells."

MT110 is the second BiTE antibody in clinical development and is currently in a phase 1 clinical trial for the treatment of patients with colorectal, gastric or lung cancers. Phase 1 and 2 clinical trials are also under way for the BiTE antibody blinatumomab (MT103, MEDI-538) in patients with non-Hodgkin's lymphoma and acute B-lymphoblastic leukemia. Updates for these two clinical trials were presented in December of 2008 at the Annual Meeting of the American Society for Hematology (ASH) in San Francisco.

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. Typically antibodies cannot engage T cells because T cells lack the appropriate receptors for binding antibodies. Previous attempts have shown the potential of T cells to treat cancer, but the therapeutic approaches tested to date have been hampered by cancer cells' ability to escape recognition by T cells. The use of BiTE antibodies that are specifically designed to engage T cells for attacking cancer cells may provide a more effective anti-tumor approach than conventional monoclonal antibodies.

About Micromet, Inc.

Micromet, Inc. (http://www.micromet-inc.com/) is a biopharmaceutical company with offices in Bethesda, Maryland and Munich, Germany. The Company is developing novel, proprietary antibodies for the treatment of cancer, inflammation and autoimmune diseases. The Company uses its proprietary BiTE(R) antibody platform to create a new class of antibodies that specifically activate T cells from the patient's own immune system to eliminate cancer cells or other disease-related cells. Four of the Company's antibodies are currently in clinical trials, with the remainder of its product pipeline in preclinical development. The Company's lead program is a BiTE antibody known as blinatumomab, or MT103. It is in a phase 2 clinical trial for the treatment of patients with acute lymphoblastic leukemia and a phase 1 clinical trial for the treatment of patients with non-Hodgkin's lymphoma. Micromet is developing blinatumomab in collaboration with MedImmune, a subsidiary of AstraZeneca plc. Micromet's second BiTE antibody in clinical development is MT110, which targets the epithelial cell adhesion molecule (EpCAM). The Company owns all rights to MT110, which is currently in a phase 1 clinical trial for the treatment of patients with solid tumors. The Company's third clinical stage antibody is adecatumumab, also known as MT201, a conventional human monoclonal antibody that targets 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. Micromet has licensed a fourth clinical stage antibody, MT293, to TRACON Pharmaceuticals, Inc. MT293 is being developed in a phase 1 clinical trial for the treatment of patients with cancer. The Company's preclinical programs include MT203, which is being developed in collaboration with Nycomed. MT203 is a traditional human antibody neutralizing the activity of granulocyte/macrophage colony stimulating factor (GM-CSF), which has potential applications in the treatment of inflammatory and autoimmune diseases, such as rheumatoid arthritis, psoriasis, or multiple sclerosis. Micromet has granted an exclusive option to Bayer Schering Pharma AG to license a BiTE antibody against an undisclosed solid tumor target. Additional BiTE antibodies, targeting CEA, CD33, Her2, EGFR and MCSP, respectively, are in different stages of preclinical development.

Forward-Looking Statements

This release contains certain forward-looking statements that involve risks and uncertainties that could cause actual results to be materially different from historical results or from any future results expressed or implied by such forward-looking statements. These forward-looking statements include statements regarding the efficacy and intended utilization of our product candidates and the development of our BiTE antibody technology. You are urged to consider statements that include the words "may," "potential," or the negative of those words or other similar words to be uncertain and forward-looking. Factors that may cause actual results to differ materially from any future results expressed or implied by any forward-looking statements include the risk that product candidates that appeared promising in early research, preclinical studies or clinical trials do not demonstrate safety and/or efficacy in subsequent clinical trials, the risk that encouraging results from early research, preclinical studies or clinical trials may not be confirmed upon further analysis of the detailed results of such research, preclinical study or clinical trial, and the risk that additional information relating to the safety, efficacy or tolerability of our product candidates may be discovered upon further analysis of preclinical or clinical trial data. These factors and others are more fully discussed in Micromet's Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2008, filed with the SEC on November 6, 2008, as well as other filings by the company with the SEC.

Any forward-looking statements are made pursuant to Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, and, as such, speak only as of the date made. Micromet, Inc. undertakes no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise.

(1) Haas C. et al. (2009). Mode of cytotoxic action of T cell-engaging BiTE antibody MT110. Immunobiology, published online on January 19;  PubMed ID: 19157637 

DATASOURCE: Micromet, Inc.



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