Case Report: Upfront sotatercept-based triple therapy in high-risk systemic sclerosis-associated pulmonary arterial hypertension

Systemic sclerosis-associated pulmonary arterial hypertension (SSc-PAH) carries a poor prognosis, and treatment decisions are often complicated by coexisting left-heart disease, lung disease, chronic thromboembolic disease, or pulmonary veno-occlusive disease-like vasculopathy. The role of sotatercept as part of initial therapy in treatment-naive SSc-PAH has not been established. We report a 60-year-old man with diffuse cutaneous systemic sclerosis, first recognized at referral 3 years after the onset of skin symptoms, and high-risk precapillary PAH. Careful evaluation showed no clinically significant parenchymal lung disease, chronic thromboembolic disease, or post-capillary physiology. Upfront therapy was started with macitentan, tadalafil, and sotatercept, with short-term dobutamine support for low-output hemodynamics. After 3 months, right heart catheterization showed marked improvement: pulmonary vascular resistance decreased from 12.6 to 3.7 Wood units, mean pulmonary arterial pressure decreased from 43 to 30 mmHg, and cardiac index increased from 1.50 to 2.90 L/min/m². World Health Organization functional class improved from III to II, and risk status shifted to low risk by REVEAL Lite 2, COMPERA 2.0, and the Japanese Circulation Society/Japanese Pulmonary Circulation and Pulmonary Hypertension Society 2025 model. No sotatercept-related adverse events were observed. This case documents the short-term course of upfront sotatercept-based triple therapy in carefully selected high-risk precapillary SSc-PAH.