Seattle Genetics takes step closer with FDA review of lymphoma drug

The folks at Seattle Genetics ($SGEN) might rest a bit easier tonight heading into an advisory committee meeting that will consider its experimental lymphoma drug later this week. An FDA staff review of the firm's drug, brentuximab vedotin, or Adcetris, appears to have produced no unexpected red flags. Yet the review did raise the question of whether the small trials completed for the drug to date offer enough evidence of its benefits.

"Small size limits the benefit-risk analysis," the FDA said in its review, as cited by Bloomberg this morning. "For this application, consideration for accelerated approval would be consistent with regulatory actions taken in the past decade for similar hematology applications based on single arm clinical trials."

With some exceptional results in small trials of the drug--which is an antibody linked to an anti-cancer toxin--many people across the biotech industry are closely watching how reviews of the treatment go this week. The FDA staff review noted safety issues in patients treated with the drug such as peripheral neuropathy, infections and a type of suppression to the immune system--but not much there that hadn't already been revealed about the drug's safety profile or what was expected from the review.

The next big test for Seattle Genetics' drug comes on Thursday, when an advisory committee of experts will weigh in on the firm's application to gain approval to market the drug as a treatment for Hodgkin lymphoma and anaplastic large cell lymphoma. If the panel recommends approval, that would be a key endorsement of its application ahead of the FDA's decision likely to come sometime next month (or by the PDUFA date of Aug. 30).

Seattle Genetics has a shot, not only at its first FDA-approved drug, but also at bringing to market the first of a class of armed antibody drugs. What makes the drugs potentially powerful weapons against cancer is that they combine the binding properties of antibodies with the killer punch of toxins. While armed antibodies offer a potential way to precisely target cancer cells, the FDA showed last year with its decision not to approve a similar type of drug, Roche's T-DM1, the technological wonders aren't immune to additional regulatory hurdles.

In its pursuit of approval of the drug, Seattle Genetics will be relying heavily on two single arm studies. Yet both studies have produced some stellar results, with its Hodgkin lymphoma trial showing the drug wiped out visible signs of disease in 34% of 102 patients, and with similar success in just over half of 58 patients with forms of anaplastic large cell lymphomas, to mention some of the key data.

While Seattle Genetics clearly has the most at stake in brentuximab vedotin's success, a regulatory win would also be a victory for its partner for commericializing the drug outside of North America, Millennium: The Takeda Oncology Company. It could also bode well for others with a stake in the armed antibody game such as developer ImmunoGen ($IMGN), which provides the linking technology for Roche's T-DM1 and has its own pipeline of such drugs.

- get the FDA staff review documents here
- read Bloomberg's report
- check out Xconomy's coverage