GlaxoSmithKline's (NYSE: GSK) Avandia is like a boxer who won't fall down. The diabetes drug has taken some major body blows over the years, including at this week's marathon Food and Drug Administration advisory committee meeting, but it still hasn't fallen.

At least, not yet.

After a series of votes asking about individual issues, the advisory committee voted yesterday on whether the drug should have additional restrictions or be pulled off the market. The results among the five options to the single question broke down like this:

  • Zero votes to remove the black box warning.
  • Three votes to keep the current label.
  • Seven votes to add additional warnings.
  • 10 votes to add additional warnings and restrict use.
  • 12 votes to remove the drug from the market.

While the largest class voted to yank the drug off the market, let's do a bit of meta-analysis data-pooling of our own: Combining the first four, 20 committee members voted to keep it on the market versus only 12 who voted to remove it. That's a win for Avandia in my book.

Of course, this is only an advisory vote; the FDA has the final say. The agency is a little more safety-conscious than it was when it decided to keep the drug on the market in 2007, and this vote was more in favor of pulling it off the market than the previous one.

If Avandia does stay on the market, it's almost certain to get an updated label. An additional warning probably won't hurt sales much more; patients and their doctors who were worried about heart issues have already switched to other diabetes drugs like Takeda's Actos and Merck's (NYSE: MRK) Januvia, so an additional warning wouldn't do much more damage.

Restrictions on use, on the other hand, could have larger repercussions for sales. If, for instance, the FDA limits prescribing to fewer doctors, we could see additional patients switching to medications like Actos, Januvia, or Onglyza from Bristol-Myers Squibb (NYSE: BMY) and AstraZeneca (NYSE: AZN). Injectable diabetes drugs such as Amylin Pharmaceuticals (Nasdaq: AMLN) and Eli Lilly's (NYSE: LLY) Byetta and Novo Nordisk's (NYSE: NVO) Victoza might even pick up a few patients.

In the bigger picture, if Avandia stays on the market, that's good news for drug-company investors. It's hard enough to predict whether drugs will get approved; worrying about the potential for a blockbuster to get pulled from the market over mixed data is a blow that most of us can't take.

Tim Hanson tells you how to discern between ugly companies and those that are too ugly.