By Frances Bishopp

After completing its review, the FDA has sent an action letter to Cor Therapeutics Inc. stating the Impact II study in angioplasty was not sufficiently robust to support approval of Cor's lead product, Integrilin.

Cor's stock (NASDAQ:CORR) closed Wednesday at $9.00, down $1.00.

The letter follows a unanimous agreement among members of the Cardiovascular and Renal Drugs Advisory Committee that, although the data indicated Integrilin had activity, a single trial did not provide enough evidence.

Integrilin, an inhibitor of platelet aggregation, is a synthetic peptide derived from the venom of southeastern pygmy rattlesnakes. Integrilin specifically blocks the Gpllb-llla receptor, which mediates platelet aggregation by binding fibrinogen.

Vaughn Kailian, president and CEO of Cor, of South San Francisco, told BioWorld Today the information the FDA seeks would be made available when, this summer, Cor unblinds its Phase III Pursuit clinical trial for Integrilin for use in connection with unstable angina. That, he said, is the largest unstable angina trial ever done.

"They knew they were going to get almost twice as much data coming in a very short period of time," Kailian said. "They want to see the data from that trial."

The current Phase III Pursuit trial for unstable angina and non Q-wave myocardial infarction has enrolled a total of 10,948 patients in the U.S., Canada, Europe and Latin America at 725 sites, 280 of which are in the U.S.

"By no means is it over for Integrilin for either indication," Kailian said. "They are looking for more supportive data and we hope the unstable angina trial will provide that."

Kailian also said he felt the FDA's new approval efficacy guidelines (see BioWorld Today, March 17, 1996, p. 1.) could possibly benefit Cor in that they address a situation where a pathological process crosses over multiple diseases.

"They specifically referred to anticoagulants that show efficacy in both unstable angina and in angioplasty, enabling you to get a claim for both," Kailian said.

Approximately 25 percent of the angina trial patients undergo angioplasty, Kailian said. "In unstable angina, there is a whole bunch of data already baked in of angioplasty patients," he said.

Cor and Schering-Plough Corp., of Madison, N.J., are worldwide partners for Integrilin under the terms of an April 1995 agreement, which paid Cor $20 million up front with another $100 million in milestones. Cor, in addition to having three-quarters of development costs covered by Schering-Plough, has the right to co-promote the product in the U.S. and Canada. After getting royalties for a period of time in Europe, Cor would gain the right to co-promote there also.

Cor will get help from Schering-Plough in developing and training a cardiovascular sales force. *