In the study, the patients were optimized on an endothelin receptor antagonist, a phosphodiesterase-5 inhibitor, or both.
The trial involved around 310 patients.
United Therapeutics’ president and chief operating officer Roger Jeffs said while they did not achieve a statistically significant result for this trial, they believe the positive results from their previously-announced Freedom-M study support an NDA filing of oral treprostinil in treatment naive patients.
"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," Jeffs said.
"We will now focus on completing the NDA for filing by the first half of 2012."