Shares of popular hedge fund pick Acorda Therapeutics (Nasdaq: ACOR) were up 25% yesterday, after it announced new clinical trial results for its lead drug.

The clinical-stage compound is designed to improve mobility for patients with multiple sclerosis. The drug, named Fampridine-SR, is in the second of two phase 3 efficacy clinical trials. These tests will serve as the foundation for an FDA marketing application, if the second study goes according to plan.

The results announced yesterday came from a safety study checking Fampridine-SR's effects on heart rhythm. The type of safety study, called a QT study, is done on nearly all drugs, and negative results with this type of clinical trial are probably the second-leading cause of most drug safety failures in clinical testing (following liver toxicity issues).

Given the jump in shares of Acorda yesterday, I don't have to tell you how the QT study turned out. The next important event for Acorda will be getting results from that second efficacy study in the second quarter of this year. Acorda's management has been a little coy about how long it will take the company to put together a marketing application if that study is successful. The company expects to get the New Drug Application into the FDA "by the first quarter of 2009."

It's been a good two years for Acorda, since the company released data from the first positive phase 3 trial of Fampridine-SR back in 2006. Fampridine-SR is an extended-release version of a drug that has shown efficacy in similar multiple exploratory clinical trials, so I expect it to reach the market.

Fampridine-SR has shown a few safety issues during its clinical testing, so it isn't out of the woods yet. In addition, it doesn't treat or delay the progression of multiple sclerosis. Even so, many interested multiple sclerosis and neurological disease-treating drugmakers like Pfizer (NYSE: PFE) or Biogen IDEC (Nasdaq: BIIB) probably wouldn't mind having a complementary drug such as Fampridine-SR in their product arsenals.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. Pfizer is a pick of the Inside Value newsletter. Biogen is a pick of the Stock Advisor newsletter. The Fool has an A+ disclosure policy.