September is shaping up to be a volatile month with quite a few drugs facing decisions by the Food and Drug Administration. The binary events can cause massive swings in share price, especially for smaller companies. Here's a few to keep your eye on.

Seeking a different FDA response
A decision about whether to expand the use of Questcor Pharmaceuticals'(Nasdaq: QCOR) Acthar Gel was supposed to come this week, but the FDA has delayed the decision. A few weeks or even a month or two isn't the end of the world. Questcor has been trying to get the drug approved for infantile spasms since 2007, when it was rejected by the FDA.

This time is likely to be different as an FDA panel voted 22-1 in favor of efficacy and 20-1 in favor of safety. Many panelists said they already use the drug off-label to treat infantile spasms, and you can't get a bigger endorsement than that.

Adding to investor confidence, Questcor said the reason for the FDA's delay was to "finalize the wording on the label, review the proposed medication guide, and define post-approval commitments, if any." If the agency was going to reject the drug, there wouldn't be much reason to discuss what's going to be on the label or trials that need to be completed after approval.

I'll be shocked if Acthar Gel doesn't get an expanded approval, but it may not add much to Questcor's revenue. The expanded approval will allow Questcor to market it legally for infantile spasm, but remember, many doctors are already prescribing it off-label to treat the disease, so sales may not increase much.

It's the same, honest
Savient Pharmaceuticals (Nasdaq: SVNT) also makes a return trip in front of the FDA this month with a PDUFA date of Sept. 14. The drugmaker is trying to get Krystexxa approved to treat gout, a painful arthritic condition.

A rejection last year was focused mostly around manufacturing of the drug. Savient wanted to change the way it made Krystexxa, but the FDA wasn't so sure the new process would create a comparable drug. (The agency also wanted an evaluation and strategies to make sure Krystexxa went to the right patients, but that seems like a lesser issue.) 

Has Savient done enough to satisfy the FDA? It's a little hard to know. Unlike safety and efficacy issues, investors don't typically get good insight into the manufacturing of a drug to spot any potential problems that might cause the FDA to give a thumbs-down.

In theory, satisfying the agency's manufacturing requirements shouldn't be that hard, but plenty of drugmakers have been tripped up several times trying to satisfy nonclinical issues with the FDA. Savient is risky simply because the risk is unknown.

Shining brighter
Predicting what the FDA is going to do with AstraZeneca's (NYSE: AZN) blood thinner Brilinta became a little more difficult in July after an FDA advisory committee voted 7-1 to recommend approval of the drug.

The FDA briefing documents sent to the panel of experts made it clear that the agency was perplexed by the data showing Brilinta worked better than Bristol-Myers Squibb and sanofi-aventis' Plavix overall, but that patients in the U.S. taking Brilinta didn't fare nearly as well.

It seemed likely that the FDA would ask for a new trial to explain the inconsistency, but the panel's vote ignoring the discrepancy might push the agency toward an approval. Of course, the FDA isn't required to follow the panel's recommendation and could still reject Brilinta.

We'll know soon enough. The FDA decision date is Sept. 16.

Needles? We don't need no stinking needles.
Novartis' (NYSE: NVS) Gilenia has one distinct advantage over multiple sclerosis drugs from Bayer, Merck KGaA, Pfizer (NYSE: PFE), Teva Pharmaceutical (Nasdaq: TEVA), Biogen Idec, and Elan (NYSE: ELN): Gilenia is taken orally, while the others have to be injected or infused.

After a 25-0 ringing endorsement of Gilenia by an FDA advisory committee, I have a hard time seeing the agency rejecting the drug even if it does have several minor issues. The only question now is, how well will it sell.

Normally, an oral drug would have no problem taking market share from established injected drugs. Needles are no fun. But doctors and patients are likely to stay focused on efficacy because multiple sclerosis is a degenerative disease. Gilenia certainly works better than placebo, but whether it works better than currently available drugs over the long term remains to be seen. Many doctors may stick with the tried-and-true treatments until Gilena gains more real-world experience.

Your friendly reminder
The PDUFA date is a goal not a deadline for the FDA. As in Questcor's case, the agency can extend the decision. Trying to jump in and out around the decision date is risky.

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