Since the Food and Drug Administration turned down InterMune's (Nasdaq: ITMN) idiopathic pulmonary fibrosis (IPF) drug, pirfenidone, last May, investors have been waiting to hear how the company planned to respond. In October, management said it would let investor know near the end of the year, and 10 days into 2011, we have an answer.

It isn't pretty.

InterMune has decided to run a new trial to gain U.S. approval. There were other options, including using data from a trial run by Shionogi, which owns the rights to pirfenidone in Japan, or applying for an accelerated approval. Either would have resulted in a much faster approval stateside, but InterMune has decided they're not viable options.

The previous trials testing pirfenidone measured patients' breathing ability after 72 weeks of treatment. Assuming the same trial length and that the company meets its goal of enrolling the first patient in the first half of this year, the earliest the trial could be done is near the end of 2012. Add in a few months to enroll all the patients, a few more to process the data, and another six-month review by the FDA, and it could be three years before InterMune sees any U.S. revenue from pirfenidone.

InterMune just moved onto my list of potential 2011 takeout targets. The obvious choice would be Gilead Sciences (Nasdaq: GILD), since Letairis just failed a phase 3 trial as a treatment for IPF. GlaxoSmithKline (NYSE: GSK) has also said it's interested in drugs treating rare diseases, and IPF certainly fits the bill. Glaxo is also well-equipped to market pirfenidone in the EU, where it recently gained a positive recommendation from regulators.

Be careful betting on a buyout though; there's always a possibility that potential suitors will let the company flounder for a while before stepping in. InterMune looks eerily similar to Encysive Pharmaceuticals, which gained EU approval for its pulmonary arterial hypertension drug, Thelin, but had a horrible time getting the FDA to sign off. Pfizer (NYSE: PFE) eventually bought the company, but not until it had dropped into penny stock land.

Today's announcement came in the form of an 8-K filing -- not a press release -- which surprises me a little given how much a U.S. approval means to InterMune. It didn't even lead with the announcement; instead, the need for a new trial was tucked in behind an announcement that it was transferring the rights to pirfenidone to a Swiss subsidiary to help lower its tax rate.

InterMune is presenting at the J.P. Morgan Healthcare Conference on Wednesday, so investors will likely get more color at the conference. Anyone want to guess how many more questions management gets about the new trial than it does about the Swiss subsidiary?

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Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.