By Mary Welch

In April 1997, when Bristol-Myers Squibb Co. said it would shut down its Seattle site focused on monoclonal antibody-based targeting therapy for cancer, some people in the company had a better idea.

"It was at that point that we went to them about possibly being spun out," said Perry Fell, president and CEO of the resulting company, Seattle Genetics Inc., of Bothell, Wash.

"We worked out a deal that's in the best interests of both," Fell said. "They gave us a whole basket full of technology."

Founded by Fell and former Bristol-Myers scientist Clay Siegall, Seattle Genetics paid Bristol-Myers a one-time cash payment for licensing the technology, agreeing to royalties on any resulting products. The new company's development platform encompasses immunotoxins, antibody-based drug conjugates, "naked" monoclonal antibodies and antibody-delivered enzyme prodrug therapy (ADEPT).

Within three years, the fledgling company expects to develop three to four novel cancer agents for clinical studies. One compound is expected to enter Phase I trials this year. "We're looking at that molecule to be in Phase I trials for breast, colon, lung and prostrate cancer, with another molecule not too far behind — 18 to 24 months — for hematologic malignancies," Fell said.

Staffed by eight employees, the company expects to add four by the end of the year, and double its staff to 24 in 1999. Seattle Genetics is working with rights gained from Bristol-Myers to ribosome inactivating proteins, among others. "The ribosome molecule has a better toxicity profile than any used to date," Fell said.

The company's ADEPT platform uses a genetically engineered antibody binding site fused to sequence and coding in enzymes which can cause an action on a relatively nontoxic prodrug and convert it to chemotherapeutic active form.

In preclinical studies, the two-step strategy regressed established human tumor xenografts. The immunotoxin uses a mechanism of action that is different from conventional chemotherapy agents, Fell said.

Last month, the company completed a Series A financing which, along with private funding, put the total of capital raised to date at $7 million. Investor groups participating in the Series A financing were Olympic Venture Partners, of Kirkland, Wash.; Sofinnova Venture Partners, of San Francisco; and Indosuez Ventures, of Menlo Park, Calif.

"We've got a lot on our plate," Fell said. "We've had opportunities for partnerships and research contracts to fund particular areas of our ADEPT approach, but we don't want to grow too quickly." *