FDA declines United's drug application

SILVER SPRING, Md. -- United Therapeutics Corp. said Tuesday that the U.S. Food and Drug Administration declined its application for an extended-release tablet version of its pulmonary arterial hypertension drug treprostinil.

The company's stock fell 8 percent in after-hours trading following the announcement.

United Therapeutics already sells injected and inhaled versions of treprostinil, which is used in the treatment of pulmonary arterial hypertension, a potentially fatal condition in which patients have abnormally high blood pressure in the arteries of the lungs.

According to the company, the FDA questioned the clinical importance of one of its studies submitted in its application and said it failed to demonstrate a statistically significant effect of oral treprostinil on how far the patients could walk in six minutes, as measured in two studies. The FDA also noted that it was unsure whether an additional clinical study could alter these impressions.

United CEO Martine Rothblatt said that the company will continue to try to gain approval for oral treprostinil and hopes to do so within the next four years.

"We will convene with our experts over the next several weeks to decide which of several paths forward to pursue," Rothblatt said in a statement.

Shares of United Therapeutics fell $4.29 in after-hours trading to $48.99. Its stock closed regular trading at $53.28, down $1.20.