CD38 and plasma cell myeloma: In clinical practice and international guidelines such as the National Comprehensive Cancer Network (NCCN) Guidelines for Multiple Myeloma (Version 2.2026), European Hematology Association and European Myeloma Network (EHA-EMN) 2025 guidelines and the International Myeloma Working Group (IMWG) guidelines for MM updated in 2024, RRMM management is more commonly stratified by the number of prior lines of therapy and the patient’s refractory status to specific drug classes, particularly IMiDs, PIs, and anti-CD38 mAbs.19,20