By Frances Bishopp

Corvas International Inc. has acquired a three-year option to purchase virtual company Vascular Genomics Inc., which will add its vascular targeting technology to Corvas' drug discovery capabilities in the cardiovascular area. The purchase will be made with Corvas stock with an aggregate value ranging from $13 million to $20 million, depending on the timing of the exercise within the option period.

The option exercise also would be automatically triggered if Corvas, of San Diego, enters into a partnering agreement having an aggregate value equal to the dollar value of the purchase price, applicable to that date. If Corvas elects not to exercise its option, Vascular Genomics could require Corvas to purchase approximately 20 percent of Vascular Genomics' outstanding stock for $3.9 million of Corvas common stock at the current value at the time.

During the option period, Corvas will fund research and development and other related costs of the technology at a rate of at least $1 million annually.

Corvas' stock (NASDAQ:CVAS) closed Tuesday at $6.375, down $0.125.

Vascular Genomics' research is being conducted at Beth Israel Deaconess Medical Center, in Boston, said George Vlasuk, executive vice president of research and development at Corvas. The company is involved in a technology that allows the selective isolation of the surface membrane of the endothelium (lining of blood vessels).

"One of the real issues in vascular biology today is trying to get things to certain blood vessels within different organs and tissues," Vlasuk said, "because there are different proteins that make up the surface."

The problem of studying the surface of the endothelium is the inability to distinguish among the many different types of membranes, he said. This technology allows selective isolation of those proteins.

Isolating these proteins can greatly enhance the efficiency of antitumor drug therapy, which can be delivered to the tumor endothelium using monoclonal antibodies recognizing unique tumor endothelial proteins.

This approach may eliminate the adverse side effects commonly associated with the current therapeutic regimens, many of which affect normal as well as cancerous tissue.

Corvas intends to use this technology first in its anticancer program to target solid tumors for treatment with both novel and established therapies.

Not only may the technology enable the transport of drug selectively to specific tissue and organs, but it also could be used to facilitate delivery of drugs across the endothelial barrier. The endothelium contains specific proteins that act as gatekeepers regulating the exposure of the underlying tissue to oxygen, nutrients and drugs, and is the primary barrier to drug delivery today.

A long-term goal for Corvas will focus on the development of a proteinomic map describing the topography of vascular proteins throughout the body in both diseased and healthy tissues. The ability to create vascular maps for specific organs could allow Corvas to become a preeminent player in the emerging field of vascular targeting, Vlasuk said.

Corvas intends to seek partnering opportunities to maximize the discoveries of endothelial markers that can help to target and transport a wide spectrum of therapeutic agents.

Corvas has received more than $25 million from its collaborations and licensing agreements to date, with another $86 million potentially available in development funding and milestone payments from current major pharmaceutical partners.

Corvas is collaborating with Pfizer Inc., of New York, for development of Corvas' neutrophil inhibitory factor (NIF), a compound derived from hookworms, to prevent brain damage associated with ischemic stroke. Pfizer exercised an option in February 1997 to retain an exclusive worldwide license to NIF and related technology.

Corvas has another major collaboration 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.

Another collaboration with Schering-Plough is in the area of hepatitis research. Under the agreement, the companies will seek orally bioavailable inhibitors of a key protease necessary for hepatitis C virus replication.

Following its current operating plan, Corvas has approximately two years of cash remaining. *