Seattle Genetics' Adcetris Meets Advisory Panel Today

By David Miller  JUL 14, 2011 9:15 AM

Contrary to popular belief, the Hodgkin's Lymphoma and ALCL treatment should be FDA approved after today's meetings.


Seattle Genetics’ (SGEN) investors are enduring an FDA advisory panel meeting for their investment’s lead drug today. In both its morning and afternoon sessions, the FDA’s Oncologic Drugs Advisory Committee (ODAC) is reviewing SGEN’s brentuximab vedotin (trade name Adcetris). The morning session is a review for approval of Adcetris in Hodgkin’s Lymphoma. The afternoon session is a review for approval of Adcetris in anaplastic large cell lymphoma (ALCL).

The punditsphere is trying to make this ODAC meeting into a referendum on accelerated approvals. The issue of accelerated approval versus full approval was the theme during the recent Avastin panel meetings. People are tarring SGEN’s meeting today with the same brush saying it is a referendum on accelerated approvals.

I don’t buy it. In fact, I buy the opposite. I believe any politics involved will work in favor of SGEN as ODAC and Richard Pazdur, the head of the FDA’s Office of Oncologic drugs, are going to use Adcetris to show cancer patients they aren’t big meanies trying to deprive people of lifesaving drugs.

The Adcetris data make this easy with a flashy overall response rate of over 70% in Hodgkin’s patients who failed all other therapies. Over 90% of patients on the trial had stable disease or better as their best tumor response. The numbers are even better for ALCL, with Adcetris showing a better response rate for relapsed patients than is typically seen in treatment-naïve patients. Side effects are not unusual.

These were single-arm trials. The Hodgkin’s trial, however, was blessed by a Special Protocol Assessment agreement between SGEN and the FDA. The ALCL indication was not so blessed, but the design purposefully similar to the Hodgkin’s trial.

So what’s the rub?

The pundits are pointing to the single-arm trial design as an issue. I don’t buy it. The FDA issued an SPA to allow it and is more than clear with industry that single-arm oncology trials are OK as long as the results are above average and the patients have truly failed all prior therapies.

The sneaker, in my opinion, is a rule created out of thin air by Pazdur requiring companies to have a confirmatory trial “substantially underway” prior to FDA granting accelerated approval. This rule has no basis on law and, in fact, is arguably in violation of regulations passed by Congress. Nevertheless, everyone follows it because Pazdur is famously “difficult” on companies who don’t listen to his every edict.

SGEN has a confirmatory trial substantially underway in earlier-stage Hodgkin’s Lymphoma. They do not have one underway for ALCL. The reason is their drug’s response rate in relapsed patients is better than currently used front-line therapy. This makes it hard to ethically and mechanistically plan a confirmatory study. SGEN does have some Phase I trials underway to examine how Adcetris will fit in with current popular front-line ALCL chemotherapy combinations, but the company is not near to launching a Phase III confirmatory trial.

This violates Pazdur’s rule. In the FDA’s briefing documents, this is mentioned and ODAC is being asked to opine on a potential confirmatory trial design.

In the end, I believe the pundits are overplaying their warnings of potential controversy. SGEN’s stock is strong enough and the investment community seems to agree with me on this one. SGEN’s Adcetris will be approved in both Hodgkin’s Lymphoma and ALCL next month, based upon a successful ODAC panel meeting outcome today.
Position in SGEN

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