United Therapeutics Corporation announced that the U.S. Food and Drug Administration (FDA) has issued new timelines for completion of a required Phase IV postmarketing study to further assess the clinical benefits of Remodulin, United Therapeutics' approved therapy for pulmonary arterial hypertension.

The FDA agreed to allow United Therapeutics an additional eighteen months to submit the final study report which is now due on December 2, 2005. The FDA also agreed to a reduction of the overall sample size of the postmarketing study from 100 to 39 patients. Additionally, an interim analysis of the study results may be performed after only 21 patients have completed the study. If these early results achieve the required interim level of significance, the study will be complete at that time. Seven patients have been enrolled in the study to date.

In May 2002, United Therapeutics agreed with the FDA to conduct the Phase IV study at the time that Remodulin was approved for the treatment of pulmonary arterial hypertension in patients with NYHA Class II-IV symptoms to diminish symptoms associated with exercise. The Phase IV study involves a randomized transition of patients treated with Flolan -- a synthetic form of prostacyclin that is delivered intravenously - to either subcutaneous Remodulin or to placebo. Outcome measures include clinical deterioration, symptoms and exercise performance.