A single-arm prospective phase I trial of 68Ga-PFBC01 PET/CT for multiple myeloma B cell maturation antigen imaging

BACKGROUNDB cell maturation antigen (BCMA) is a key therapeutic target in multiple myeloma (MM), yet its whole-body in vivo distribution and role in disease assessment remain incompletely defined. We aimed to evaluate the safety, diagnostic performance, and clinical utility of a novel BCMA-targeted PET tracer, 68Ga-PFBC01, in patients with plasma cell disorders.METHODSWe conducted a single-center, prospective, single-arm phase I trial (ClinicalTrials.gov NCT06717113). Fifty patients underwent 68Ga-PFBC01 PET/CT, including 40 with paired 18F-FDG PET/CT for head-to-head comparison. Primary outcomes included diagnostic performance (sensitivity, specificity, PPV, NPV, and interreader agreement). Secondary outcomes included correlations with clinical biomarkers, treatment response assessment, impact on clinical decision-making, and safety.RESULTS68Ga-PFBC01 PET/CT demonstrated superior diagnostic performance compared with 18F-FDG PET/CT (sensitivity 96.9% versus 84.6%; specificity 71.4% versus 60.0%). Quantitative PET-derived tumor burden correlated with M protein (R = 0.325, P = 0.026), free light chains (R = 0.340-0.437, P ≤ 0.015), soluble BCMA (R = 0.433, P = 0.050), and bone marrow plasma cells (R = 0.682, P < 0.001). Imaging findings altered clinical management in multiple cases, enabling both therapy escalation and deescalation. Blood-pool uptake strongly correlated with soluble BCMA (R = 0.899, P < 0.001) and overall disease burden (R = 0.736, P < 0.001). No serious tracer-related adverse events were observed; 2 patients (4%) experienced mild events.CONCLUSION68Ga-PFBC01 PET/CT provides biologically specific, whole-body assessment of MM, outperforming 18F-FDG and enabling integrated evaluation of tumor burden and systemic disease activity, with direct implications for clinical decision-making.TRIAL REGISTRATIONClinicalTrials.gov NCT06717113.FUNDINGNational Natural Science Foundation of China (82472018, 82402320), Beijing Nova Program (20240484725), National High Level Hospital Clinical Research Funding (Interdisciplinary Research Project of Peking University First Hospital, 2024IR07, Scientific and Technological Achievements Transformation Incubation Guidance Fund Project of Peking University First Hospital, 2025CX38, 2024CX18). Research Achievement Transformation Project of Peking University First Hospital, 2025ZH02), Clinical Medicine Plus X - Young Scholars Project of Peking University, the Fundamental Research Funds for the Central Universities (PKU2026PKULCXQ038).