B-cell maturation antigen targeted PET/CT imaging in multiple myeloma: a first-in-human study.

B-cell maturation antigen (BCMA)-targeted positron emission tomography/computed tomography (PET/CT) represents a promising tool for the management of multiple myeloma, enabling noninvasive and quantitative evaluation across different disease stages. This novel technique specifically addresses two major diagnostic challenges: the limited specificity of conventional 18F-FDG PET/CT and the focal sampling constraints of bone marrow biopsies. In this prospective study, a 68Ga-labeled nanobody-based BCMA tracer demonstrated improved detection compared with 18F-FDG PET/CT, effectively visualizing para-medullary, extra-medullary and medullary lesions, as well as minimal residual disease (MRD). The tracer also reflected dynamic changes in BCMA expression associated with treatment response, underscoring its potential utility for guiding BCMA-targeted interventions, particularly in the era of chimeric antigen receptor T-cell (CAR-T) treatment. These preliminary findings support the potential of BCMA immunoPET as a comprehensive, noninvasive modality for MM evaluation and warrant validation in larger, prospective clinical trials.