It might not be quite as much fun as a three-day Park Hopper at Disneyland, but biotech investors are in for a three-day treat next week when three companies head in front of Food and Drug Administration advisory committees.

Fueling up
First up is NPS Pharmaceuticals' (NASDAQ: NPSP) Gattex on Oct. 16. Gattex treats short bowel syndrome, which is a side effect of extensive resection of the bowel due to Crohn's disease, ischemia or other conditions. The short digestive track reduces the ability to absorb nutrition, water, and electrolytes, so patients have to supplement their meals with intravenous feeding, called parenteral nutrition.

The phase 3 trial supporting its marketing application met its primary endpoint of reducing the volume of parenteral nutrition after 20 weeks and 24 weeks of treatment. Twice as many patients taking Gattex (63%) reduced their volume of fluids by 20% compared to those taking placebo (30%). Even with the small number of patients, just 43 in each treatment group, the difference was so substantial that the p-value was a minuscule 0.002. Or put another way, there's a 0.2% chance that it happened randomly.

Safety looked just as good. Four patients dropped out of the study because of adverse events, but three of those were taking placebo.

The only thing I can really see the agency complaining about is that the drug was only tested in 43 patients, which isn't a whole lot considering this will be a long-term treatment. NPS rolled most of the patients in the phase 3 trial into an open-label trial to get longer-term data, which is expected to be completed in early 2013. Hopefully the fact that data is coming soon will be enough to alleviate any concerns the FDA or the advisory panel has.

European regulators didn't bother waiting for the extended data. Last month, the drug was approved in Europe, where it's called Revestive and sold by NPS' partner Takeda Pharmaceutical. European approval isn't a guarantee that the drug will be approved stateside, but it should increase investors' confidence that there aren't any huge red flags that might keep it from getting approved in the U.S.

A cholesterol two-for
On Wednesday and Thursday, a different panel, the Endocrinologic and Metabolic Drugs Advisory Committee, will review two cholesterol-lowering drugs. Both drugs treat patients with homozygous familial hypercholesterolemia, or HoFH, where mutations in both copies of a gene cause patients' cholesterol levels to be off the chart despite treatments with current offerings like Merck's (MRK 2.13%) Zetia, Pfizer's (PFE -2.27%) Lipitor, and AstraZeneca's (AZN 5.77%) Crestor.

Both Aegerion's (NASDAQ: AEGR) lomitapide and mipomersen, being developed by Isis Pharmaceuticals (IONS -0.80%) and Sanofi (SNY 5.84%) substantially reduce cholesterol levels; efficacy isn't likely to be an issue at the advisory committee meeting.

Safety, on the other hand, could trip up the drugs. Both cause fat buildup in the liver, which can lead to long-term damage. But HoFH patients' arteries are so clogged with cholesterol plaques that they typically die of heart attacks or strokes by the time they're 30. Given the unmet need, I expect most doctors on the panel will brush off the side effects.

The fun starts early
Keep in mind that the FDA usually posts the briefing documents for the committee members two business days before the meeting, so the documents for the Gattex review will come tomorrow, with lomitapide and mipomersen following on Monday and Tuesday next week.

The briefing documents are typically more important than the actual meeting because they give investors a picture of what the FDA reviewers are thinking. The advisory committee votes are just a recommendation, and the FDA has the final say, so strongly negative briefing documents should be a red flag that it will take an amazingly positive panel to change the agency's mind.

Predictions
It's always challenging to predict how an advisory committee will vote. The committee spends all day discussing the drug, and depending on the chair of the committee, a member or two can take over the discussion, convincing the rest of the panel that a minor issue is a deal breaker.

With that caveat, all three drugs look like they should get through their binary events with recommendations for approval from their respective advisory committees. None are likely to be as tame as a ride on Disneyland's Autotopia -- there would be no reason to have the committee meeting if they were -- but I don't expect jarring Space Mountain-type meetings either.