Oral Treprostinal (United Therapeutics) attracts Complete Response Letter from FDA

A Complete Response Letter was received by United Therapeutics from the FDA declining to approve its new drug application (NDA) for treprostinil diethanolamine extended release tablets (oral treprostinil) for the treatment of Pulmonary Arterial Hypertension (PAH).

The FDA letter questioned the clinical importance of the 6 Minute Walk Distance (6MWD) effect size shown in the FREEDOM-M study, the inability to demonstrate an improvement in time to clinical worsening in all three Phase III studies of oral treprostinil, and the inability to demonstrate a statistically significant effect on 6MWD in the two FREEDOM-C studies as reasons for being unable to approve the NDA in its current form. The FDA noted that it was unsure whether an additional clinical study could alter these impressions, but if United Therapeutics did undertake an additional study it should consider, among other things, a fixed dose design and more frequent dosing.