Shares of Australian-based specialty pharmaceutical company Pharmaxis (NASDAQ:PXSL) were up 17% last week, after the company reported that the U.S. Food and Drug Administration gave its lead product for cystic fibrosis, Bronchitol, fast track designation.

It was surprising to see shares of Pharmaxis up so much after this announcement, because fast track designation is not an affirmation by the FDA of a drug's efficacy or safety, but is rather a designation that a drug treats a serious disease that has few other treatments available. When a drug gets fast tracked, the FDA may approve the product based only on a single phase 3 trial, rather than the two it normally requires if the drug shows "substantial evidence" that it does what it claims to do.

The other benefit to a fast track designation is that Pharmaxis will be able to submit a new drug application on a "rolling basis" as the different parts of its application get finished, rather than having to wait until it's all completed to file it with the FDA. But being able to file on a rolling basis won't help Bronchitol get approved any sooner. After all, the countdown for a final regulatory response from the FDA won't start until an application has been completed. All it means is that Pharmaxis may save a few months if a problem crops up in the drug's application, as the FDA may notify Pharmaxis of the problem ahead of the final review.

Pharmaxis' Bronchitol is in a phase 3 trial and has enrolled over one-third of the trial's 350 total patients. Enrollment is expected to be completed by the end of the year and the endpoint of the trial is the drug's effectiveness after 12 weeks of use. Therefore, trial results should be out around the middle of next year and Pharmaxis expects to submit a completed application sometime in 2008.

Even if Bronchitol receives a priority review from the FDA, the drug won't be on the market until late 2008 or early 2009, if it eventually gets approved. Fast tracking might accelerate a drug's journey to the market, but it doesn't make the road ahead for Pharmaxis and Bronchitol much easier.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has a disclosure policy.