Corvas International Inc. reported that preliminary analyses of a Phase IIb study of UK-279,276 in ischemic stroke show that it failed to meet its primary endpoints and therefore does not support a Phase III trial.

The study was conducted by Pfizer Inc., of New York, which entered a collaboration with Corvas to develop the product a neutrophil inhibitory factor formerly known as rNIF in 1997. (See BioWorld Today, Feb. 25, 1997.)

“The preliminary analyses that Pfizer had done as it relates to the primary endpoints did not support going forward with a Phase III in stroke,” said Randall Woods, president and CEO of San Diego-based Corvas.

Corvas’ stock (NASDAQ:CVAS) plummeted $2.83 Wednesday, or 47.3 percent, to end the day at $3.15.

Woods said Corvas expects to have final results from Pfizer at the end of June, and at that point it will be determined whether Pfizer will go forward with a Phase III trial or whether it will make other decisions on how to proceed.

“Pfizer does have the worldwide exclusive right for all indications,” Woods said. “Until it has had an opportunity to analyze the complete data set, we won’t know what its plans are.”

The Phase IIb study did not meet the primary endpoints of neurological and functional outcomes as measured by standard stroke indices in the Canadian Stroke Index, he said.

“What that really means is, Do patients walk and talk better?’” Woods said.

To date, Pfizer has paid Corvas $4.4 million in a deal that has a potential to earn milestones of $31.4 million, Woods said. Woods emphasized that Pfizer has responsibility for all development costs, but he could not say how much the pharmaceutical company has spent on development of UK-279,276.

“It is not as though Corvas has continued to spend money,” Woods said, saying that factor helps mitigate the impact of the “disappointing” Phase IIb results.

However, Woods said the results will have minimal impact on Corvas’ financials. In reporting earnings on Tuesday, Corvas, which has $100 million in cash, revised its guidance on its burn rate for 2002, now expecting to spend in the “low $30 million” area, as opposed to the “high $20 million” it had previously estimated.

Woods pointed to the company’s pipeline to balance the negative news from the Phase IIb. The company is scheduled to begin a Phase IIb trial with its anticoagulant, rNAPc2, in acute coronary syndrome in the second half of this year.

“What we would like to do is go into this Phase II trial,” Woods said. “We anticipate having positive results, and would like to partner before going into Phase III.”

In December, Corvas reported results from a Phase IIa study of rNAPc2 that showed it appeared to be safe and well tolerated when administered to patients prior to elective percutaneous transluminal corornary angioplasty. The study also showed that, in contrast to standard therapy with heparin and aspirin alone, it suppressed the formation of thrombin, a serine protease related to blood clotting.

Corvas’ cancer pipeline, all of which is preclinical, focuses on modulating the activity of serine proteases associated with the growth and progression of solid tumors.

The company is in a collaboration with Dyax Corp., of Cambridge, Mass., to work together on identifying cancer drug candidates. The other collaboration is with Incyte Genomics Inc., of Palo Alto, Calif., whereby Corvas will use Incyte’s genomic database.

“It is now known in cancer literature that serine proteases play a key role in cancer,” Woods said, explaining that Corvas is taking four approaches in its cancer research, including looking at small molecules and monoclonal antibodies.

“We actually have leads,” he said. “We do not have anything in the clinic, but we have forged some collaborations that will help.”