Selexipag for chronic thromboembolic pulmonary hypertension in japanese patients - A double-blind, randomized, placebo-controlled, multicenter phase II study

Background: Selexipag is an oral prostacyclin receptor (IP receptor) agonist with a non-prostanoid structure. This study examined its efficacy and safety in Japanese patients with non-operated or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH). Methods and Results: This Phase II study was a randomized, double-blind, placebo-controlled parallel-group comparison. The primary endpoint was a change in pulmonary vascular resistance (PVR) from baseline to week 17. The main analysis involved a per-protocol set group of 28 subjects. The change in PVR (mean ±SD) after 17 weeks of treatment in the selexipag group was -104±191dyn·s/cm⁵, whereas that in the placebo group was 26±180dyn·s/cm⁵. Thus, the treatment effect after 17 weeks of selexipag treatment was calculated as -130±189dyn·s/cm⁵(P=0.1553). Although the primary endpoint was not met, for the group not concomitantly using a pulmonary vasodilator the PVR in the selexipag group was significantly decreased compared with placebo group (P=0.0364). The selexipag group also showed improvement in total pulmonary resistance and cardiac index. Conclusions: Selexipag treatment improved pulmonary hemodynamics in Japanese patients with CTEPH, but PVR did not show a significant difference between the selexipag and placebo groups.