Seattle Genetics therapy trial encouraging

Seattle Genetics said Monday that its cancer therapy SGN-35 showed encouraging results in an early-stage clinical trial, boosting the strength of its pipeline of product candidates.

The data could make the firm more attractive to prospective partners or buyers, an analyst said.

The Bothell-based company said that more than 75 percent of enrolled patients, most of them with relapsed Hodgkin's disease, saw their tumors shrink after treatment.

The study is still in progress, but the results were so promising that Seattle Genetics decided to release an interim report, said Chief Executive Clay Siegall.

"We felt it was important enough data to release the information to the medical community," Siegall said.

This is the second Seattle Genetics product candidate to have clinical data supporting its claims. Early results for the company's lead product, a blood-cancer therapy known as SGN-40, drew Genentech in January into a development partnership potentially worth hundreds of millions. Seattle Genetics plans to announce early-stage clinical results for a third anti-cancer product, SGN-33, next month.

"We're transitioning from a company with one product with one strong clinical proof concept to a company that has three products," Siegall said.

The data could pave the way for a lucrative partnership similar to the Genentech deal, or an attract acquisition offer from Big Pharma or a large biotech company, said David Miller, a Seattle-based analyst with Biotech Stock Research.

SGN-35's experimental performance adds luster to Seattle Genetics' proprietary antibody-drug conjugate (ADC) technology, which the company employs in two other experimental therapies, currently at the preclinical stage. This method enables antibodies that target cancer cells to carry oncology drugs directly to them.

"The speed with which Seattle Genetics gets acquired by another [company] is related to the quality of the data for SGN-35," said Miller. "The quality of this data was pretty good."

The results, however, did not give Seattle Genetics' stock a boost. Shares dropped 3.14 percent Monday to $10.49.

Seattle Genetics is not in a hurry to partner up with Big Pharma on this product, but it doesn't rule out that option either, Siegall said.

"The longer you hold these types of products the more value they get," he said. "But if the deal is strong enough with the right company and the right setup, yes, we'd consider it."

Ángel González: 206-515-5644

or agonzalez@seattletimes.com