Thursday, Aug 15, 2002

U.S. PTO Interference Declared in Genentech/Chiron Patent Dispute

South San Francisco, Calif. -- August 15, 2002 --

Genentech, Inc. (NYSE: DNA) today announced that on August 12, 2002, the United States Patent and Trademark Office declared an interference between the Chiron patent currently involved in a lawsuit with Genentech and a patent application exclusively licensed by Genentech from the University of Pennsylvania relating to anti-HER2 antibodies. In declaring this interference, the Patent Office has determined that there is a substantial question as to whether the inventors of the Chiron patent were first to invent this technology and are entitled to this patent.

An interference proceeding is declared by the Patent Office to decide who first made a particular invention where two or more parties claim the same invention, whether the parties' claims are patentable, and consequently who is entitled to a patent on the invention. If the Patent Office were to decide that the inventors of the University of Pennsylvania patent application were first to invent this technology and that their claims are patentable, a new patent would issue to them and the Chiron patent would be revoked.

Genentech is a leading biotechnology company that discovers, develops, manufactures and commercializes biotherapeutics for significant unmet medical needs. Fifteen of the currently approved biotechnology products originated from or are based on Genentech science. Genentech manufactures and commercializes ten biotechnology products directly in the United States. The company has headquarters in South San Francisco, California, and is traded on the New York Stock Exchange under the symbol DNA.