As I mentioned these past two weeks, there was an FDA Advisory Committee (AdComm) meeting on July 13 and 14 that reviewed the safety of the diabetes drug Avandia (rosiglitazone). Transcripts of the sessions will someday be posted at the FDA website, at 2010 Meeting Materials, Endocrinologic and Metabolic Drugs Advisory Committee but until then, I've found an excellent resource that reviews the proceedings, session-by-session, at Forbes.com.

The FDA proposed a list of questions that the Advisory Committee was asked to vote upon; they are posted at the FDA website (the outcome of the votes are mentioned in the Forbes.com blogs). To me, the key question was the following: "Based on the available data, which of the following regulatory actions do you recommend FDA pursue regarding rosiglitazone?" The options the 33 Advisory Committee members were given were:

"A. Allow continued marketing and revise the current label to remove the boxed warning and other warnings regarding an increased risk of ischemic CV events, or
B. Allow continued marketing and make no changes to the current label, or
C. Allow continued marketing and revise the current label to add additional warnings (e.g., contraindications for certain patient populations, recommendation for second-line use in patients intolerant of or uncontrolled on other anti-diabetic agents); or
D. Allow continued marketing, revise the current label to add additional warnings, and add additional restrictions on use (such as restricting prescribing to certain physicians or requiring special physician and patient education)
E. Withdrawal from the U.S. market."

The results of the voting for this question are fascinating:

* No one voted for option A, to remove the restrictions that already exist in the Avandia label. No surprise here, as the panel clearly thought, based on earlier votes, that Avandia has a cardiovascular risk.

* Three members of the AdComm voted for option B, to continue the present wording of the label without any changes.

* Seven voted for option C, to revise the wording of the label to make it scarier.

* Ten voted for option D, to revise the wording of the label to make it scarier, and also to restrict the use of Avandia in other ways.

* Twelve voted for option E, to withdraw Avandia from the U.S. market.

* And one AdComm panelist chose not to vote.

Some writers have spun the story that the majority (21 out of 33) are willing to allow continued marketing of Avandia. Others have pointed out that 22 out of 33 want the use of Avandia curtailed either mostly or completely. But the big issue is how the FDA will interpret the Advisory Committee's votes. Remember that the FDA is not obliged to automatically follow the recommendations of their Advisory Committees, even if the vote was overwhelmingly one way or the other. In this case, the split decision by the panelist leaves the FDA with a very unclear message on exactly which path to take: to strengthen warnings and restrictions on its sale or have the drug removed from the market.