First-in-Human Evaluation of 18FAldoView: A Highly Selective PET Tracer for Aldosterone Synthase Imaging in Primary Aldosteronism

OBJECTIVES: Aldosterone synthase (CYP11B2) is overexpressed in primary aldosteronism (PA), making it a promising target for imaging. This first-in-human study evaluates the safety and feasibility of 18 FAldoView, a highly selective PET tracer targeting CYP11B2, for PA subtyping. METHODS: Biodistribution and dosimetry of 18 FAldoView were assessed in 3 healthy volunteers using whole-body PET/CT. Fifteen patients with adrenal lesions (13 with PA, 1 with Cushing's syndrome, and 1 with a nonfunctional adenoma) were enrolled. PET/CT scans were performed 60 minutes postinjection. Lesions were considered positive if tracer uptake exceeded normal adrenal tissue. Semi-quantitative analyses included maximum standardized uptake value (SUVmax), lesion-to-liver ratio (LLR), and lesion-to-adrenal ratio (LAR). Ten PA patients with positive imaging findings and 1 with Cushing's syndrome underwent adrenalectomy, and resected specimens were analyzed for CYP11B2 expression. This ongoing study is registered with the Chinese Clinical Trial Registry (ChiCTR2400093214). RESULTS: 18 FAldoView was well-tolerated, with no adverse events. The effective dose was 0.012±0.0022 mSv/MBq. PET/CT identified positive lesions in all 10 PA patients, with a mean SUVmax of 15.73±8.57, LAR of 8.02±4.06, and LLR of 10.24±1.48. No positive lesions were observed in patients with idiopathic hyperaldosteronism, Cushing's syndrome, or nonfunctional adenomas. Positive lesions showed strong CYP11B2 staining on pathology, confirming aldosterone-producing adenomas (APA) or nodules (APN). CONCLUSIONS: 18 FAldoView PET/CT is safe and feasible for the imaging of APAs and APNs in PA patients. These results highlight its potential for noninvasive in vivo detection of CYP11B2, supporting its use in PA subtyping.