As with many drugs, fatal adverse events have been detected during postmarketing surveillance of Genentech Inc.'s Herceptin trastuzumab anti-HER2 monoclonal antibody to treat breast cancer. While such side effects were not seen in the company's clinical trials, DNA does not believe that the adverse events raise general safety concerns about Herceptin use.

DNA last week issued a Dear Doctor letter notifying health care providers of 62 postmarketing reports of serious adverse events, including hypersensitivity, infusion and pulmonary reactions (see Online Links, A11, & BioCentury Extra, Thursday May 4). A total of 15 deaths were reported out of the estimated