By Charles Craig

Corvas International Inc. could receive more than $31 million from Pfizer Inc. in a collaboration for development of the former’s neutrophil inhibitory factor (NIF), a compound derived from hookworms, to prevent brain damage associated with ischemic stroke.

In October 1995, New York-based Pfizer paid Corvas, of San Diego, $1.1 million for an option to develop NIF. To proceed with the alliance, Pfizer Monday agreed to pay another $1 million plus $29 million in development funding and milestones.

Pfizer, in return, received a worldwide license to develop, manufacture and market NIF. Corvas will assist Pfizer, but the pharmaceutical company will be responsible for all clinical development costs. Corvas also will receive royalties.

Pfizer’s first milestone payment, said John Crawford, Corvas’ chief financial officer, will be worth $1 million and will be triggered by submission to the FDA of an investigational new drug application to begin clinical trials with NIF.

Crawford said preclinical toxicology tests have to be performed before human trials can begin.

Corvas has received about $2.5 million from Pfizer since the initial research and option agreements were negotiated 16 months ago.

NIF, discovered in parasitic hookworms by Corvas scientists, blocks the activation of neutrophils, or white blood cells, which damage brain tissue during the reperfusion that follows removal of the stroke-inducing blood clot.

The neutrophils, Crawford said, are dispatched by the immune system in response to the ischemia. Once blood flow is restored to the brain, the white cells, normally rallied to attack bacteria, end up killing healthy tissue.

NIF would be considered an acute care treatment. The compound does not act on the blood clot causing the stroke, but could be used along with a drug targeting removal of the obstruction.

Corvas has another major corporate partnership with Schering-Plough Corp., of Madison, N.J., for development of two oral anticoagulants; one inhibits thrombin and the other Factor Xa, an enzyme involved earlier in the coagulation cascade than thrombin.

In addition to NIF, hookworms are the source of Corvas’ nematode anticoagulant proteins (NAP), one of which the company is expected to take into clinical trials beginning in March or April for deep vein thrombosis.

Corvas’ stock (NASDAQ:CVAS) Monday closed at $7, a $1.125 increase. *