Chiron Sues Rival Genentech Over Breast Cancer Drug

Chiron Corp. said Thursday it had filed a patent infringement lawsuit against rival California biotech company Genentech Inc. alleging that the manufacture and sale of Genentech’s breast cancer drug Herceptin infringed a Chiron patent.

Chiron said the suit, filed in the U.S. District Court for the Eastern District of California, asserts that a Chiron patent awarded April 25 covers monoclonal antibodies that bind selectively to human breast cancer cells--specifically to the HER-2 antigen that Herceptin targets.

“The newly issued patent is the latest in a series of patents first issued in 1988 to Cetus Corp., which later was acquired by Chiron,” Chiron said in a prepared release.

“These patents, based upon an application originally filed in 1984, reflect Chiron’s work to identify specific antigens that can be used to diagnose and treat breast cancer,” Chiron said.

Herceptin, a monoclonal antibody, is one of Genentech’s largest sources of revenue. It had sales in 1999 of more than $188 million, which set a record for first-year sales of any cancer treatment.

Genentech spokeswoman Sabrina Johnson said her company, based in South San Francisco, plans to vigorously defend itself. “And we have every confidence the courts will find in our favor,” she said.

Chiron, based in Emeryville, Calif., said it has not sought injunctive relief, and Herceptin is “anticipated” to remain on the market while a patent resolution is sought.

Chiron, which is 44% owned by Swiss drug maker Novartis, rose $1.31 to $41.75 on Nasdaq. Genentech, which is majority owned by Swiss drug maker Roche Holding, lost $2.13 to close at $125.13 on the New York Stock Exchange.