FDA declines approval of United Therapeutics PAH drug

SILVER SPRING, Md. — The Food and Drug Administration has declined to approve a drug developed by United Therapeutics Corp. for treating a potentially lethal high blood pressure condition.

The drug maker said it received a complete response letter from the agency for its application for a tablet formulation of the drug treprostinil. The company already markets the drug in injectable and inhaled formulations for pulmonary arterial hypertension, or PAH, a condition that causes high blood pressure in the arteries of the lungs.

The FDA issues a complete response letter when it has finished reviewing a regulatory application for a drug, but questions remain that preclude approval. The FDA's letter called into question the importance of a measure of efficacy called "6-minute walk distance," or 6MWD, and also raised concerns about the inability to show a significant effect on 6MWD in one of the clinical trials and the inability to show an improvement in time to clinical worsening.

"We will continue using our best efforts to gain approval of oral treprostinil, and we will focus on doing so within the next four years," United chairman and CEO Martine Rothblatt said. "We will convene with our experts over the next several weeks to decide which of several paths forward to pursue."

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