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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
15
\[68Ga\]Ga-FAPI PET/CT
\[68Ga\]Ga-MAA PET/CT
Chu Brest
Brest, Finistere, France
Vascular remodeling as assessed by [68Ga] Ga-FAPI uptake of pulmonary arteries on PET/CT imaging.
A positive uptake will be defined as a ratio of the Standardized uptake value (SUV) max of the pulmonary arteries and the SUVmean of the vascular background activity measured at the center of the left ventricle greater than 1.5.
Time frame: at baseline
Change from baseline in [68Ga] Ga-FAPI uptake on pulmonary arteries as assessed by SUVmax at 24 weeks.
\[68Ga\] Ga-FAPI uptake on pulmonary arteries. This will be assessed using a visual scale and the Standardized uptake value (SUVmax).
Time frame: At baseline and at 24 weeks.
Visual assessment of pulmonary artery [68Ga]Ga-FAPI uptake
Change from baseline in regional lung perfusion as assessed by the Pulmonary vascular obstruction index (PVOI) (in %) on \[68Ga\]Ga-MAA lung perfusion PET/CT imaging at 24 weeks.
Time frame: At baseline and at 24 weeks.
[68Ga] Ga-FAPI uptake on the right ventricule (RV) assessed by SUVmax at 24 weeks.
Time frame: At week 24
RV ventricule dysfunction based on Tricuspid annular plane systolic excursion (TAPSE)<17mm at 24 weeks.
Time frame: At 24 weeks.
Change from baseline in [68Ga] Ga-FAPI uptake on the RV as assessed by SUVmax at 24 weeks.
Time frame: At baseline and at 24 weeks.
Mean pulmonary arterial pressure (mPAP) (in mmHg) at baseline.
mPAP will be measured by right Heart catheterism (RHC).
Time frame: At baseline.
Cardiac output (CO) (l/mn) at baseline.
CO will be measured by RHC.
Time frame: At baseline.
Right atrial pressure (RAP) (mmHg) at baseline.
RAP will be measured by RHC.
Time frame: at baseline
Right ventricular pressure (RVP) (mmHg) at baseline.
CO will be measured by RHC.
Time frame: At baseline.
Pulmonary vascular resistance (PVR) (Wood unit) at baseline.
CO will be measured by RHC.
Time frame: At baseline.
Mean pulmonary arterial pressure (mPAP) (mmHg) at 24 weeks.
mPAP will be measured by right Heart catheterism (RHC).
Time frame: At 24 weeks.
Cardiac output (CO) (l/mn) at 24 weeks.
CO will be measured by RHC.
Time frame: At 24 weeks.
Right atrial pressure (RAP) (mmHg) at 24 weeks.
RAP will be measured by RHC.
Time frame: At 24 weeks.
Right ventricular pressure (RVP) (mmHg) at 24 weeks.
CO will be measured by RHC.
Time frame: at baseline
6 minutes walking test result (6MWT) (meters) at baseline.
Time frame: At baseline.
Vascular remodeling on [68Ga]Ga-FAPI PET/CT is correlated with Nt-proBNP measure in PAH patients
\[68Ga\] Ga-FAPI uptake on pulmonary arteries (SUVmax) will be correlated with Nt-proBNP measure in PAH patients
Time frame: at baseline
6 minutes walking test result (6MWT) (meters) at 24 weeks.
Time frame: At 24 weeks.
NYHA functional class at baseline.
The New York heart association (NYHA) scale will be used to classify the severity of the heart failure impact. Classes are defined as I, II, III, IV, with IV indicating severe limitations
Time frame: At baseline.
NYHA functional class at 24 weeks.
The New York heart association (NYHA) scale will be used to classify the severity of the heart failure impact extent of heart failure. Classes are defined as I, II, III, IV, with IV indicating severe limitations.
Time frame: At 24 weeks.
N-terminal pro B natriuretic peptide (NT-pro-BNP) (pg/ml) at baseline
biological mark indicating heart failure and impact on PH prognosis
Time frame: At baseline.
N-terminal pro B natriuretic peptide (NT-pro-BNP) (pg/ml) at 24 weeks.
biological mark indicating heart failure and impact on PH prognosis
Time frame: At 24 weeks.
Quality of life (QOL) assessed by emPHasis-10 scale at baseline.
The emPHasis-10 ranges from 0 to 50, with a higher score indicating a poorer health status and QOL.
Time frame: At baseline.
QOL assessed by emPHasis-10 scale at 24 weeks.
The emPHasis-10 ranges from 0 to 50, with a higher score indicating a poorer health status and QOL.
Time frame: At 24 weeks.
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