IN THE PIPELINE: Micromet Grabs Immune System In Cancer Fight

8th Jun 2010 16:00

By Thomas Gryta Of DOW JONES NEWSWIRES NEW YORK (Dow Jones)--Micromet Inc. (MITI) is developing drugs that use an aggressive approach to using the body's own defenses in fighting cancer. Unlike Dendreon Corp.'s (DNDN) recently approved Provenge, which works like a vaccine to stimulate an immune response against prostate cancer, Micromet's drugs harness the immune system by reaching out and grabbing it. While years away from the market, the concept has already proved effective in midstage studies, attracted the attention of major pharmaceutical companies, and eventually may have uses beyond cancer. The body's immune system uses a variety of methods to protect itself, including T-cells that hunt and destroy outside invaders. But cancer cells have a way of cloaking themselves against detection by T-cells, something that Micromet's drugs aim to stop. They are called bispecific T-cell engagers, or BiTE antibodies, and they are designed to attach to both cancer cells and to T-cells, thus killing the cancer. "It is a simple idea. We wanted to come up with a class of drugs that prompt the patient's own T-cells to engage and destroy cancer cells," Chief Executive Christian Itin said. Needham & Co. analyst Mark Monane believes the drugs represent the next generation of antibody therapy by giving them "extra killing power" in cancer. Other companies are developing next-generation antibodies that work in other ways, including Seattle Genetics Inc. (SGEN), Immunogen Inc. (IMGN) and Roche Holding AG (ROG.VX, RHHBY). Monane said that development of such drugs can be comforting to investors because many of the drugs are going after already established targets on the cancer cell and may be less risky. Antibodies are produced by the immune system and bond to threats, such as bacteria or a virus, in order to neutralize them. Traditional therapeutic antibodies are proteins that are designed to bond with a single substance or site on a cell for a specific purpose. For example, Roche's Avastin bonds to a protein called VEGF produced by tumors that is involved in the blood-vessel generation that is necessary for cancer to grow. The structure of BiTE antibodies is different because it bonds to two different things, one being on the cancer cells themselves, while the other is the T-cells already in the body. Micromet has a number of similar drugs in development, most of which haven't been tested in humans yet. They use the link to T-cells, but have different binding targets with their other arm. The lead program is called blinatumomab, which binds to a site called CD-19 on the cell surface of many blood cancers. After seeing stronger than expected activity of blinatumomab in acute lymphocytic leukemia, or ALL, an aggressive form of blood cancer that is more common in children, the company decided to focus its efforts on the disease. Currently, the treatment for ALL is long-term use of intense chemotherapy. Last year, a midstage trial of the drug showed that 80% of a group of patients with traces of ALL after receiving extensive chemotherapy had undetectable cancer after using blinatumomab. The patients were free of relapse for up to 15 months. "That information triggered quite a shift in how we're thinking about the path forward," Itin said. Following work in ALL, the company will proceed with developing the drug in advanced non-Hodgkin lymphoma. The company is in talks with regulators and planning a number of clinical trials of blinatumomab in ALL in adults and children. It expects to begin two studies later this year and another two next year, with the final data likely coming in 2013. The opportunity could be big. Monane estimates that yearly sales of blinatumomab in ALL could reach $300 million to $500 million, and twice that in non-Hodgkin lymphoma. The second BiTE antibody in development binds to a site called EpCAM, which appears in several different solid tumors including colorectal cancer, ovarian cancer and stomach cancer. In addition, Micromet is working on a number of other targets in BiTE antibodies and has collaborations with AstraZeneca PLC (AZN.LN, AZN), Bayer AG (BAY.XE, BAYRY), Sanofi-Aventis SA (SAN.FR, SNY) and Boehringer Ingelheim GmbH (BRI.YY). While Itin said the company will focus on cancer for "quite a while," he notes that the BiTE antibodies could have future usefulness in certain inflammatory or infectious diseases. (Thomas Gryta covers the biotech and generic-drug industries for Dow Jones Newswires. He can be reached at 212-416-2169 or by email at [email protected].) (TALK BACK: We invite readers to send us comments on this or other financial news topics. Please email us at [email protected]. Readers should include their full names, work or home addresses and telephone numbers for verification purposes. We reserve the right to edit and publish your comments along with your name; we reserve the right not to publish reader comments.) (END) Dow Jones Newswires June 08, 2010 11:00 ET (15:00 GMT)