Tuesday, June 03, 2008

GSK’s Promacta at ASCO: Advisory Committee “Show and Tell”

When it comes to finding ways to recruit new members for its advisory committees, the Food & Drug Administration is getting pretty creative.

Having already undertaken various activities to fill vacancies among its expert panels, FDA embarked on the Ultimate Roadshow at the American Society of Clinical Oncology’s annual meeting last week in Chicago: a committee review of GlaxoSmithKline’s eltrombopag (Promacta), a non-peptide oral platelet growth factor for the treatment of idiopathic thrombocytopenic purpura.

As the saying goes, if you can’t bring the candidates to the advisory committee, bring the advisory committee to the candidates. And we’ve got to hand it to FDA: what better opportunity to attract new members then to hold a meeting smack dab in the middle of one of the biggest medical conferences of the year?

FDA has been working to fill advisory committee vacancies for some time—by creating a central database for committee openings and asking medical associations to nominate potential candidates. But there are still more than 100 openings between the drugs and biologics review centers alone. (For a breakdown by advisory committee, check out this chart in the latest issue of “The Pink Sheet.”)

The committee that reviewed Promacta at ASCO, the Oncology Drugs Advisory Committee, or ODAC, currently has four vacancies. Compared to other advisory committees, oncology isn’t doing too badly: the Dermatologic and Ophthalmic Drugs Advisory Committee, for example, has 12 vacancies, and the Anesthetic and Life Support Drugs Advisory Committee has nine.

But the decision to hold Promacta’s review at ASCO is based less on ODAC’s relative need for additional committee members, and more on the vision of the lead oncology reviewer at FDA, Richard Pazdur. (For more on Dr. Pazdur, check out our earlier story in the The RPM Report; those who don’t subscribe can sign up for a free trial.)

Pazdur is quite dedicated to an open, transparent review process. Summaries of ODAC’s meetings, for example, are published in peer-review journals. By scheduling the Promacta meeting during ASCO, oncologists have a “convenient opportunity to observe first-hand the processes and issues that are considered during an ODAC meeting,” FDA says.

With any luck, the agency says, some of those oncology experts in the audience might become interested enough to serve on the committee. Hence, “it can also serve as a recruitment tool.”

Pazdur has done this sort of thing before: Promacta is actually the second committee meeting to be held off-site at a medical conference. At Pazdur’s suggestion, Bristol-Myers Squibb’s dasatinib (Sprycel) for chronic-phase chronic myeloid leukemia was the lucky subject of a committee review during the ASCO conference in June 2006.

We say “lucky” because Sprycel was unanimously recommended for approval, and was quickly cleared for marketing later that month. Likewise, Promacta was recommended for approval by a 16-0 vote, despite concerns that eltrombopag’s marketing plan includes, according to FDA, a risk management program that encourages off-label use.

With a sample size of two—and FDA's final say on Promacta's approvability still outstanding—we suppose it is premature to assume that a cancer treatment would have an easier time getting past an FDA advisory committee held in the midst of the greatest oncology R&D love fest in the world. But it is something to think about.

So far, none of the other FDA review divisions have followed Pazdur’s lead. But it may make good sense. Consider this: the Dermatologic and Ophthalmic Drugs Advisory Committee May 29 review of Sirion Therapeutics’ difluprednate (Durezol) convened with just four voting members. That's a lot of power in the hands of just a few people.

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