By Randall Osborne

A month after agreeing to pay $335 million to Roche Holding Ltd. for rights to the recombinant tissue plasminogen activator Retavase, Centocor Inc. has been sued by Genentech Inc. for alleged infringement of patents related to the product, used to treat myocardial infarction.

On Tuesday, South San Francisco-based Genentech was issued patents on variant forms of tPA and immediately sued Centocor, said Paul Laland, spokesman for Genentech.

"One [patent] is for the process and the other is for the product," said Laland, who declined to comment further.

Paul Wulfing, Centocor's senior director of communications, also declined to discuss the suit.

"We haven't had the opportunity to review the lawsuit itself, so it would be inappropriate for me to comment," Wulfing said.

Genentech has been waging legal battles over tPA for years. The company manufactures and markets Activase, a tPA clot-buster for heart attacks, pulmonary embolism and stroke. Sales of Activase last year fell 8 percent to $260.7 million, a drop the company blamed in part on Retavase's entry into the marketplace. (See BioWorld Today, Jan. 23, 1998, p. 1.)

In February, Centocor, of Malvern, Pa., agreed to buy Retavase rights in the U.S. and Canada from Roche, which had acquired them as part of its $11 billion purchase last May of Hamilton, Bermuda-based Corange Ltd., the parent company of Boehringer Mannheim GmbH, against which Genentech also has patent litigation ongoing. (See BioWorld Today, May 28, 1997, p. 1.)

The war has been scientific as well as legal. In March 1997, Boehringer released results of its Global Utilization Studies for Thrombolysis of Occluded Arteries (GUSTO), which the company conducted to prove Retavase clinically superior to Activase.

GUSTO showed the two products clinically equivalent, although Genentech said the results indicated Activase works better for acute myocardial infarction. (See BioWorld Today, March 18, 1997, p. 1.)

Retavase is expected to complement Centocor's other clot-fighting drug, ReoPro, a monoclonal antibody that inhibits platelet aggregation. ReoPro is marketed by Indianapolis-based Eli Lilly and Co.

Centocor's stock (NASDAQ:CNTO) closed Wednesday at $40.062, down $0.625. Genentech (NYSE:GNE) ended the day at $69.375, up $0.062. *