The drug, PRX-08066, is a novel 5-HT2B antagonist that the company believes represents a new mechanism of action for treating pulmonary hypertension (PH). Epix said that PRX-08066 resulted in statistically significant reductions in systolic pulmonary artery pressure (SPAP); responder (greater than or equal to 4mmHg drop in SPAP) rates were 45% on 400mg once-daily vs. 14% on placebo.
The Massachusetts-based biopharmaceutical company said that the therapy was also well-tolerated, with potential for co-administration with other therapies.
The phase IIa study was a randomized, double-blind, placebo-controlled trial of 71 patients with PH associated with chronic obstructive pulmonary disease (COPD). Patients were randomized to one of three arms: 200mg of PRX-08066 once-daily; 400mg of PRX-08066 once-daily; or placebo.
In a population where decreases of 3mmHg to 4mmHg in a post-exercise SPAP are considered clinically significant, 45% of the patients in the 400mg group had a reduction in post-exercise SPAP of 4mmHg or more versus 14% on placebo. As observed in prior trials, PRX-08066 had no effect on systemic blood pressure, further demonstrating its selective pulmonary vasodilatory action.