New Compound Targeting Receptor Tyrosine Kinase EphA2 Shows Tumor Destruction at Low Dose Levels in Preclinical Models

GAITHERSBURG, MD, and CARLSBAD, CA, USA | Apr 19, 2007 | MedImmune, Inc. (Nasdaq: MEDI) and Micromet, Inc. (Nasdaq: MITI) today announced that published proof-of-concept data with a new BiTE(R) molecule (bscEphA2xCD3) show that the compound killed tumor cells at dose levels considerably below those required by classical monoclonal antibody-based therapies. The in vitro and in vivo data, collected from cell culture experiments conducted under the companies’ BiTE(R) technology research collaboration, were published in the April 15, 2007 issue of Cancer Research.

BiTE molecules represent a novel class of drugs that function as bi- specific T-cell engagers. They are unique in their ability to enable the body’s killer T cells to recognize and attack tumor and target cells, leaving normal cells unharmed. bscEphA2xCD3 is a BiTE molecule targeting the tyrosine kinase receptor EphA2, which is frequently overexpressed on a wide variety of solid tumors.

"The results of this study show that a receptor tyrosine kinase may be an appropriate target for a BiTE molecule," said Patrick Baeuerle, Ph.D., Micromet’s Chief Scientific Officer. "This highlights the breadth of the BiTE technology for creating molecules that target different kinds of antigens. Recognition of selected sites on a target antigen may provide a means to widen the therapeutic window for this highly potent therapeutic approach."

In the preclinical study, tumor cell destruction approached 100 percent even at low ratios of effector T cells to target cells. In animal models, the BiTE compound redirected unstimulated human T cells to inhibit outgrowth of transplanted human tumor cells. Time-lapsed videomicroscopy showed that bscEphA2xCD3 triggered T cells to destruct tumor cells overexpressing EphA2, but spared normal cells where the tyrosine kinase was sequestered within intercellular boundaries.

Under the terms of the companies’ BiTE research collaboration agreement, MedImmune holds the rights to bscEphA2xCD3. Micromet may receive milestone and royalty payments based on the successful development and commercialization of the compound and has the option to co-promote the product in Europe. Under a separate agreement, Micromet and MedImmune collaborate on the development of MT103/MEDI-538, a BiTE molecule being developed to treat B-cell non-Hodgkins lymphoma.

"As a result of our collaboration around this novel technology platform, MedImmune’s portfolio of potential cancer treatments has expanded to include several BiTE molecules targeting a range of tumor types," said Peter Kiener, MedImmune’s Senior Vice President, Research. "As a company committed to developing innovative therapies for patients with cancer, we are encouraged by the broad therapeutic potential and promising biologic activity that these molecules have shown to date."

About BiTE(R) Molecules:

BiTE(R) molecules are a novel class of antibody derivatives with the potential to selectively direct and activate an individual’s cytotoxic T cells, the body’s most potent killer cells, to act against cancer cells. MT103/MEDI-538, a BiTE specific for the B cell antigen CD19, provided clinical proof-of-concept for the BiTE platform technology, as presented at the last meeting of the American Society for Hematology. In an ongoing phase 1 study, MT103/MEDI-538 has shown potent elimination of tumor target cells in peripheral blood, bone marrow, lymph nodes and spleen of therapy-refractory non-Hodgkins lymphoma patients.

About MedImmune, Inc.

MedImmune strives to provide better medicines to patients, new medical options for physicians, rewarding careers to employees, and increased value to shareholders. Dedicated to advancing science and medicine to help people live better lives, the company is focused on the areas of infectious disease, cancer and inflammatory diseases. With more than 2,500 employees worldwide, MedImmune is headquartered in Maryland. For more information, visit the company’s website at www.medimmune.com.

About Micromet, Inc. (www.micromet-inc.com)

Micromet, Inc. is a biopharmaceutical company focusing on the development of novel, proprietary antibody-based products for cancer, inflammatory and autoimmune diseases. Two product candidates are currently in clinical trials. MT103/MEDI-538, which is the first product candidate based on Micromet’s proprietary BiTE(R) product development platform, is being evaluated in a phase 1 clinical trial for the treatment of patients with non-Hodgkins lymphoma. The BiTE product development platform is based on a unique, antibody-based format that leverages the cytotoxic potential of T cells, the most powerful ‘killer cells’ of the human immune system. Adecatumumab (MT201), a recombinant human monoclonal antibody which targets EpCAM expressing tumors, has completed two phase 2a clinical trials, one in patients with breast cancer and the other in patients with prostate cancer. In addition, a phase 1b trial evaluating the safety and tolerability of MT201 in combination with docetaxel is currently ongoing in patients with metastatic breast cancer. Micromet has established collaborations with MedImmune, Inc. for MT103/MEDI-538 and Merck Serono for adecatumumab (MT201).

Forward-Looking Statements of MedImmune, Inc.

This announcement contains, in addition to historical information, certain "forward-looking statements" regarding the development of a novel BiTE(R) molecule (bscEphA2xCD3) targeting the tyrosine kinase receptor EphA2 to treat certain cancers. Such forward-looking statements are based on current expectations and involve inherent risks and uncertainties, including factors that could delay, divert or change and could cause actual outcomes and results to differ materially from current expectations. In addition to risks and uncertainties discussed in MedImmune’s filings with the U.S. Securities and Exchange Commission, no assurance exists that development efforts for any such product will succeed, that any such product will receive required regulatory approval or that, even if regulatory approval is received, any such product will be commercially successful. MedImmune undertakes no obligation to update any forward-looking statement, whether as a result of new information, future events or otherwise except as may be required by applicable law or regulation.

Forward-Looking Statements of Micromet, Inc.

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. Such forward-looking statements include statements regarding the intended utilization of product candidates, the conduct and results of future clinical trials, plans regarding regulatory filings, future research, discovery of new product candidates, and clinical trials, and partnering activities. Factors that may cause actual results to differ materially include the risk that product candidates that appeared promising in early research and clinical trials do not demonstrate safety and/or efficacy in larger-scale or later clinical trials, the risks associated with regulatory processes, the risks associated with reliance on outside financing to meet capital requirements, and the risks associated with reliance on collaborative partners for future revenues under the terms of its existing collaboration agreements, and for further pre-clinical and clinical studies, development and commercialization of product candidates. You are urged to consider statements that include the words "may," "will," "would," "could," "should," "believes," "estimates," "projects," "potential," "expects," "plans," "anticipates," "intends," "continues," "forecast," "designed," "goal," or the negative of those words or other comparable words to be uncertain and forward-looking. These factors and others are more fully discussed in Micromet’s periodic reports and other filings with the SEC, including the "Risk Factors" sections of such reports.

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 and MedImmune undertake no obligation to publicly update any forward- looking statements, whether as a result of new information, future events or otherwise.

SOURCE: Micromet, Inc.