Identifying potential parameters associated with response to switching from a PDE5i to riociguat in RESPITE

•In RESPITE, 51 patients switched to riociguat from sildenafil or tadalafil.•Exercise capacity, biomarkers & functional class improved from baseline to Week 24.•Sixteen patients (31%) met a combined responder endpoint of clinical improvement.•At baseline, responders had higher REVEAL risk scores and exercise capacity.•Hemodynamic and cardiac function parameters improved in responders at Week 24.