TGFB1 and pulmonary arterial hypertension: High affinity ligands of ACTR2A include Activin A, GDF8, and GDF11,49 which levels are all increased in PAH.89,90,101 Due to the promiscuous role of ACTR2A in complex formation and binding capacity to many other ligands (also e.g. BMP10),49 we stress that Sotatercept’s success might rely on its unspecific targeting of TGFβ ligands.