United vows to file NDA on PAH drug after it flunks Ph3

United Therapeutics' late-stage oral drug for pulmonary arterial hypertension flunked a Phase III study, failing to add any significant improvement in walking distance after 16 weeks of therapy. But the company ($UTHR) says it nevertheless has all the data it needs to win an FDA approval, which it plans to seek early next year.

Investors weren't quite as sanguine about the trial failure. Soon after the news was released its stock plunged more than 20%.

United's investigators have been working on an oral formulation of treprostinil, a synthetic form of prostacyclin which is already available in subcutaneous, intravenous and inhaled formulations. In the Freedom-M study researchers recruited 310 patients and divided them into two groups, either getting a standard therapy plus treprostinil or a placebo. But after more than three months of treatment, preliminary data indicated that the drug combo arm saw a placebo-corrected improvement of only 10 meters for a 6 minute walk, short of statistical significance.

"While we did not achieve a statistically significant result for this trial, we believe the positive results from our previously-announced Freedom-M study support an NDA filing of oral treprostinil in treatment naive patients," said United President and COO Roger Jeffs. "Given that treprostinil is already approved for use in PAH by subcutaneous, intravenous and inhaled routes of administration, we believe the data obtained from all Freedom trials support an NDA for oral treprostinil in this indication. We will now focus on completing the NDA for filing by the first half of 2012."

- here's the United release