About 30 percent of breast cancers and some other cancers overexpress the HER-2 growth factor receptor. The marker is associated with aggressive disease, rapid progression and shortened survival. Therapies targeted at HER-2 are beginning to demonstrate efficacy in the subpopulation of cancer patients who overexpress the receptor, suggesting that HER-2 is a valid target for treatment as well as a marker.

In normal breast tissue, HER-2 receptors on the cell surface are believed to play a role in normal cell growth by signaling cell division. When cancer cells overexpress HER-2, however, extra receptors form. Their higher density elicits accelerated cell division, contributing to tumor growth.

At least three companies developing compounds targeting HER-2 presented data at the American Society of Clinical Oncology meeting in Los Angeles last week. Genentech Inc. announced additional data from two pivotal studies of its Herceptin trastuzumab humanized anti-HER2 monoclonal antibody. Earlier stage clinical reports came from Medarex Inc. with its MDX-210 bispecific antibody in prostate cancer and kidney cancer patients, and Corixa Corp. with its HER-2/neu vaccine in breast and ovarian cancer.


GNE (South San Francisco, Calif.), which submitted a BLA to the FDA earlier this month and has Fast Track designation for the product, presented results of a trial coupling Herceptin with chemotherapy versus chemotherapy alone in 469 women.