It seems like every other week we get to hear about a new delay for Encysive's (NASDAQ:ENCY) lead drug Thelin. Two weeks ago, it was the U.S. Food and Drug Administration rejecting Encysive's approvable letter response because of an incorrectly formatted data table. Today Encysive announced that the FDA accepted its response letter but was granting it a 180-day review rather the shorter 60-day review it had received for its previous approvable letter response back in May.

This will be the third go-round for Thelin with FDA. The drug first received an approvable letter from the FDA back in March and a request for more clinical trials with the drug. Encysive thought it could respond to the approvable letter questions without more trials, but the FDA issued another approvable letter again in July with one more unresolved issue in question.

The class 2 review that Encysive received for Thelin yesterday is usually reserved for companies that file substantially new information about their drug in regulatory review. Getting this review is bad in the sense that the wait is going to be a couple months longer than hoped for, but good in the sense that it likely means a thorough review that may help finally get Thelin approved this go-round.

The date by which the FDA plans to make a decision on Thelin is set for June 15 of next year. The lead for Encysive's launch of Thelin in the U.S. is now at a couple of months at most over its rival, Ambrisentan, made by Gilead Sciences (NASDAQ:GILD) if Gilead can get Ambrisentan approval on the first go-round.

Thelin has been on the market in the United Kingdom since November and in Germany for a couple of weeks, so the drug should bring in a couple of million dollars to Encysive this quarter. Nonetheless, with a 50-person U.S. sales force sitting idle for nearly a year and cash levels running low, Encysive will definitely need to raise yet more cash via an equity financing now that the wait has been longer than expected for Thelin's approval.

Who here is at fault for all these delays? It really doesn't matter whether it's the FDA's or Encysive's fault. The fact is that Encysive has lost its expected nearly two-year lead over Ambrisentan in the U.S. The worst part of all this waiting is that Encysive hasn't revealed what the holdup has been at this point. Encysive has no good reason not to tell investors what the problem and delay related to gaining Thelin marketing approval has been related to.

Now that Gilead has submitted an application to market Ambrisentan, revealing what the holdup is with Thelin's approval will not bring any major competitive disadvantages to Encysive since Gilead isn't going to be going back and redoing its New Drug Application all over again. Regardless, with shares of Encysive down more than 20% yesterday, investors can only hope that the third time is the charm for Thelin's approval from the FDA.

Encysive Pharmaceuticals is a Rule Breakers recommendation.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article.