Macitentan use was associated with improvements in right ventricular (RV) function in pulmonary arterial hypertension (PAH), according to research presented at the 68th Annual Scientific Session and Expo of the American College of Cardiology held March 16-18 in New Orleans, Louisiana.

Researchers conducted a 52-week open-label multicenter study (Right Ventricular Remodeling in Pulmonary Arterial Hypertension [REPAIR]; ClinicalTrials.gov Identifier: NCT02310672) to evaluate the effect of macitentan on RV remodeling and function, either as monotherapy or in combination with a phosphodiesterase-type 5 inhibitor.

Changes in RV stroke volume (RVSV) as determined by pulmonary artery flow MRI and pulmonary vascular resistance (PVR) via right heart catheterization from baseline to week 26 served as the 2 primary end points.

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A total of 42 patients (mean age, 46.3 years; 31 women) were evaluated. The median 6-minute walk distance was 376 meters, and 19 patients were considered WHO functional class II and 23 patients were considered WHO functional class III.

At week 26, the RVSV was significantly increased (mean change, 50.7 vs 67.3 mL) and PVR (mean change, 900 vs 540 dyn.sec.cm-5) was significantly decreased. Study enrollment ended as a result of the primary end points being met.

In a primary efficacy analysis, the model-adjusted least squares mean change in RVSV was 15.2 from baseline to week 26 (2-sided P <.0001), and the model-adjusted geometric mean ratio in PVR was 0.63 (37% reduction; 2-sided P <.0001).

The researchers concluded that REPAIR is the first PAH study to use an MRI variable as a primary end point that demonstrated improved RV function with macitentan treatment.

Reference

Rosenkranz S, Galiè N, Channick R, et al. Effects of macitentan on right ventricular remodeling in pulmonary arterial hypertension: results from the REPAIR study interim analysis. Presented at: the 68th Annual Scientific Session and Expo of the American College of Cardiology; March 16-18, 2019; New Orleans, LA. Abstract 902-06.