Tuesday, May 28, 1996

Patent Infringement Suit Filed Against Boehringer

South San Francisco, Calif. -- May 28, 1996 --

Genentech, Inc. (NYSE: GNE) today announced the filing of a suit for patent infringement and a declaratory judgment of patent infringement in the Federal District Court for the District of Massachusetts against Boehringer Mannheim GmbH and Boehringer Mannheim Corporation.

The suit alleges that by using, selling, offering to sell or importing into the United States their thrombolytic agent Reteplase, the companies infringe five Genentech patents relating to Activasereg. (Alteplase, recombinant). Reteplase is a variant recombinant tissue plasminogen activator (rt-PA). The patents include those disclosing basic methods for recombinant production of proteins, methods for making quasi-synthetic genes, methods for making modified t-PA by amino acid deletions, methods for purifying recombinant-produced proteins and methods for increasing the solubility of t-PA in pharmaceutical compositions.

"Having carefully evaluated the patent situation, we firmly believe that Boehringer Mannheim has infringed patents held by Genentech and that we will prevail," said Stephen Raines, Genentech's vice president for Intellectual Property.

Genentech is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for unmet medical needs. The company has headquarters in South San Francisco and is traded on the New York and Pacific stock exchanges under the symbol GNE.

MEDIA CONTACT: Paul Laland (415) 225-2742
INVESTOR CONTACT: Diane Schrick (415) 225-1599

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