REPAIR: long-term effects of macitentan on the right ventricle (RV) in pulmonary arterial hypertension (PAH)

Introduction: In a study of patients (pts) with PAH (REPAIR), macitentan improved RV stroke volume (RVSV) and measures of RV function at Week 26. Aims and objectives: To assess if effects of macitentan at Week 26 were maintained at Week 52. Methods: REPAIR (NCT02310672) was a 52-week, multicentre, open-label, single-arm phase 4 study. Macitentan 10mg was initiated in treatment-naive PAH pts, in pts receiving stable background phosphodiesterase type-5 inhibitor (PDE5i) at baseline (BL), or in initial combination with PDE5i. RV MRI variables, 6-minute walk distance (6MWD) and WHO functional class (FC) were assessed at Weeks 26 and 52. Results: Analyses included 71 pts (80% female; BL: median age 45 years, median 6MWD 395 [Q1, Q3: 323, 483] m, 98.6% FC II/III. At Weeks 26 and 52, mean (95% CL) change from BL in 6MWD was 36 (19, 52) and 38 (19, 57) m; FC improved in 40/70 (56%) and 34/65 (48%) pts; no pts worsened. The table shows RV parameter changes at Weeks 26 and 52. Conclusions: Improvements in RV mass, volume and function observed with macitentan at Week 26 were maintained at Week 52.