CD38-Targeted Molecular Imaging Probes for Multiple Myeloma: Advances, Challenges, and Opportunities.

Multiple myeloma (MM), the second most common hematologic malignancy, often presents with a gradual onset and minimal symptoms in its early stages, leading to frequent misdiagnosis and delays in treatment. In recent years, radionuclide-based molecular imaging has emerged as a pivotal tool in the noninvasive evaluation and clinical management of MM, particularly in assessing the expression of CD38─a transmembrane glycoprotein that is robustly expressed on approximately 80-100% of malignant plasma cells. Notably, clinical studies have revealed a negative correlation between CD38 expression levels and treatment outcomes, underscoring the importance of accurate and dynamic measurement of CD38 for diagnostic precision and individualized treatment stratification. Radiolabeled molecular imaging targeting CD38 enables repeated, in vivo assessments of its expression status, allowing clinicians to monitor molecular heterogeneity and temporal changes throughout disease progression or therapeutic intervention. To this end, a variety of CD38-targeted imaging agents have been developed, including monoclonal antibodies, antibody fragments, nanobodies and peptide. Many of these probes are currently undergoing preclinical evaluation or have entered early phase clinical trials. This review summarizes recent advances in the development and application of CD38-targeted molecular imaging probes in MM, highlighting their potential to improve disease characterization, therapeutic monitoring, and personalized management strategies.