Activin pathway inhibition and rapid progression of malignancy in pulmonary arterial hypertension: A case series and hypothesis.

The increased risk of malignancy in PAH and the immunologic duality of activin raise important questions about the long-term implications of activin signal inhibitors, particularly in patients with preexisting or latent malignancies. Emerging real-world observations raise questions regarding potential associations between sotatercept exposure and malignancy development or progression. We describe a series of malignancies that occurred in patients treated with sotatercept. While these cases do not establish causality, they highlight the need for vigilance and further study.