Long-term outcomes with initial triple oral therapy in pulmonary arterial hypertension (PAH): Insights from TRITON

In the randomized controlled TRITON (NCT02558231) study, both initial triple oral (macitentan, tadalafil, selexipag) and initial double oral (macitentan, tadalafil, placebo) therapy improved PVR (primary endpoint; by 54% and 52%) and 6-minute walk distance (secondary endpoint; by 55 and 56 m) at wk 26 in patients with newly diagnosed PAH, with no difference between groups. We analysed the treatment effect on the secondary endpoint of time to first disease progression event (centrally adjudicated) until end of the observation period +7 days and time to all-cause death (post-hoc) until end of the observation period (Cox regression model). Baseline characteristics were balanced between the initial triple (n=123) and initial double therapy (n=124) groups, median follow-up was 77.6 and 75.8 wks, respectively. There was a 41% reduction in the risk of first disease progression event with initial triple vs initial double therapy (hazard ratio 0.59, 95% CI 0.32–1.09, p=0.087; Figure), driven by PAH-related hospitalisation and all-cause death. Adverse events were consistent with known safety profiles of study drugs. Two patients died in the initial triple therapy group and 9 in the initial double therapy group (hazard ratio 0.23, 95% CI 0.05–1.04). Exploratory analysis indicated a signal for improved long-term outcome with initial triple versus initial double therapy.