Sotatercept: First experience in Eisenmenger Patients

All articles of this category (opens in new window) Background: Sotatercept, an activin signaling inhibitor, is approved for the treatment of adult patients with pulmonary arterial hypertension since 2024. Monitoring of the platelet levels as well as Hb is mandatory. Increased Hb levels have been observed, which may lead to hyperviscosity syndrome and increased risk for thromboembolic events. Eisenmenger syndrome represents an extreme form of pulmonary hypertension with severe pulmonary vascular disease, which is characterized by a right-to-left shunt, hypoxemia, and erythrocytosis. Although Eisenmenger patients often survive for decades, their physical exercise tolerance is very limited. Other advanced therapies for PAH have been proven to be beneficial in this patient group. Methods: We offered Sotatercept to selected Eisenmenger patients with moderate polycythemia (Hb < 20 g/dL), no history of bleeding or thrombosis. We aimed to assess tolerability and safety. Results: Two patients with Eisenmenger physiology in FC 2 and 3 (both female, aged 29 and 31) have been treated with Sotatercept for 4 and 7 months, respectively. Treatment was well tolerated by both patients. One patient reported a temporary gingival bleed. Hb did not increase significantly in either patient, nor did we observe any other adverse serological changes. Transcutaneous oxygen saturation seemed to improve, as well as the patients’ exercise tolerance. NT-pro BNP decreased, suggestive of less myocardial strain. Conclusion: Sotatercept appears to be well tolerated and leads to improved physiological markers and potential improvement of exercise tolerance, even in Eisenmenger patients. In particular, Hb did not appear to rise significantly in this cohort with a physiologically higher baseline Hb, maybe due to improved pulmonary blood flow. A planned study of Sotatercept in patients with Eisenmenger physiology with structured monitoring will hopefully reveal the long-term benefits of this therapy in this challenging patient cohort. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany