Tuesday, October 14, 2008

Nearing an End to the Longest Review?

Ovation reached a milestone this month in its quest to get its GABA-transaminase inhibitor vigabatrin (Sabril) on the market: It received confirmation from the Food & Drug Administration of a tentative date for an advisory committee meeting.

Given that FDA has held 30 advisory committee meetings so far this year, that doesn’t sound like groundbreaking news. But in the case of Sabril, it’s a major development given the difficulty FDA has had in finding enough qualified advisory committee members under the new conflict of interest guidelines.

We wrote about Sabril as a worst-case example of the approval delays in the new user fee era in last month's issue of The RPM Report. But is also a poster child for what can go wrong under FDA's new conflict of interest guidelines. (We'll have more on that on this blog and in the next issue of The RPM Report.)

But for now, here's the short story: An advisory committee meeting for Sabril was originally scheduled for August, but there was one (tiny) hiccup. It turns out that the only pediatric neurologist on the committee, Dartmouth Medical Centers Greg Holmes, did work on the original NDA when it was owned by Sanofi-Aventis predecessor company Marion Merrell Dow.

That’s a definite no-no under FDA’s new guidelines. Holmes was recused, and it has taken until now for the agency to reschedule the meeting for January 7-8, as reported in this week's issue of "The Pink Sheet." Of course, that’s assuming FDA can find a qualified pediatric neurologist who hasn’t run a clinical trial for vigabatrin (or a competitor), or invested more than $50,000 in Ovation (or a competitor), or is conflicted in some other way.

But perhaps the Greg Holmes snafu is only fitting for a drug like vigabatrin, which has already had an excruciatingly long pathway toward approval.

Vigabatrin was developed in the 1980s by Merrell Dow as an anticonvulsant. Three advisory committee were convened (in 1984, 1985 and 1989) in light of toxicity signals seen in animal models. An NDA finally was submitted in 1994 by Marion Merrell Dow; FDA turned it down twice before it was outlicensed to Ovation in 2004 by Aventis (now Sanofi-Aventis).

Ovation has had much more success with vigabatrin, having moved from the licensing deal to a priority review for a more targeted indication of infantile seizures in three years. (Ovation also is pursuing the original indication for use in complex partial seizures; the company submitted a response to FDA's questions about that application late last year.)

FDA's deadline for a decision on both indications was June 27--more than three months ago. Between the missed user fee deadline and the immense difficulty in finding enough experts to staff an advisory committee, Sabril is the worst-case example of drug regulation today.

Will there be more? Probably. Will it be yours? Stay tuned.

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