Impact of Sotatercept on Pulmonary Artery and Right Ventricle Remodeling Imaging Assessed With 68Ga-FAPI PET/CT in Patients With PAH

Pulmonary arterial hypertension (PAH) is a rare, progressive disease characterized by structural changes in the pulmonary arteries, leading to increased pulmonary vascular resistance and elevated pulmonary arterial pressure and, if untreated, right heart failure. Diagnosis requires a comprehensive evaluation, including right heart catheterization performed in specialized centers. Despite advances in the understanding and management of the disease, PAH remains a severe condition. Current approved therapies primarily target three key pathways involved in endothelial dysfunction: the endothelin, nitric oxide, and prostacyclin pathways. Pulmonary arterial remodeling is characterized by alterations in endothelial cells, smooth muscle cells, and fibroblasts, with fibroblast activation and macrophage involvement contributing to disease progression. Two positron emission tomography/computed tomography (PET/CT) imaging approaches are currently under investigation in PAH. \[⁶⁸Ga\]Ga-FAPI PET/CT targets activated fibroblasts and enables noninvasive assessment of fibroblast activity and tissue remodeling. \[⁶⁸Ga\]Ga-MAA lung perfusion PET/CT is an emerging imaging technique that provides higher spatial resolution and sensitivity than conventional lung perfusion imaging and allows evaluation of regional pulmonary perfusion. Sotatercept is a novel fusion protein that modulates signaling within the transforming growth factor-beta (TGF-β) superfamily by binding select ligands involved in vascular remodeling. Its mechanism of action is distinct from that of currently approved PAH therapies. Sotatercept has been evaluated in clinical development programs, including the PULSAR and STELLAR studies. Reported adverse events include epistaxis, dizziness, increased hemoglobin levels, and changes in blood pressure. This study is designed with the following objectives: Primary objective: To assess pulmonary vascular remodeling in patients with PAH using \[⁶⁸Ga\]Ga-FAPI PET/CT imaging. Secondary objectives: To evaluate \[⁶⁸Ga\]Ga-FAPI uptake and regional lung perfusion using \[⁶⁸Ga\]Ga-MAA lung perfusion PET/CT imaging at predefined study time points.

NCT Number	NCT07357974
Lead Sponsor	University Hospital, Brest
Conditions	Pulmonary Arterial Hypertension (PAH)
Enrollment	15 participants
Start Date	2026-07-15
Primary Completion	2028-01-01 (estimated)
Study Completion	2028-01-01 (estimated)
Updated on ClinicalTrials.gov	2026-06-16