Comparative Analysis of Survival in Pulmonary Arterial Hypertension for Patients Treated with Selexipag in Clinical Practice (EXPOSURE Study).
Background: In pulmonary arterial hypertension (PAH), comparative assessment of treatment effect on survival in randomized controlled settings of contemporary patients has not been feasible.
Objective: The aim of this study was to use EXPOSURE, the ongoing, real-world, post-authorization safety study, and commitment to the European Medicines Agency to perform pre-specified comparative survival analyses between patients that newly initiated selexipag versus other PAH-specific therapies by applying statistical methods to account for population differences.
Methods: EXPOSURE (EUPAS19085) is an observational study comprising patients with PAH who initiated selexipag or other PAH-specific therapy. To balance characteristics of patients in the other PAH therapy cohort with the selexipag cohort at PAH therapy initiation (baseline), propensity score weighting was applied. Mortality rate ratios (MRRs) were calculated.
Results: 2014 patients were available for analysis. Prior to applying propensity score weighting, patients in the selexipag cohort were more likely to have longer time from diagnosis, less functional impairment, and treatment with combination background therapy versus the other PAH therapy cohort. Following weighting, baseline variables for both cohorts were well balanced. Weighted treatment exposure was 827.9 and 840.5 person-years for the selexipag and modelled other PAH therapy cohort, respectively. Weighted proportion of deaths was lower in the selexipag versus modelled other PAH therapy cohort; MRR showed a higher survival rate for selexipag-treated patients (MRR [95% confidence interval]: 0.55 [0.31-0.99]).
Conclusions: Survival analyses in EXPOSURE suggest a reduced risk of mortality among the cohort of patients newly initiated on selexipag compared with the modelled cohort newly initiated with other PAH-specific therapies. Further research is needed to confirm this observation. Background: Trial registration: EUPAS19085.