Soluble B‐cell maturation antigen in multiple myeloma

Abstract

B‐cell maturation antigen (BCMA) has emerged as a promising immunotherapeutic target in multiple myeloma (MM) management, with the successive approval of antibody‐drug conjugates, bispecific antibodies, and chimeric antigen receptor T‐cell therapies directed to this membrane receptor. Soluble BCMA (sBCMA), a truncated version produced through gamma‐secretase cleavage, can be quantified in serum/plasma samples from patients with MM via electrochemiluminescence, fluorescence, or enzyme‐linked immunosorbent assays, as well as through mass spectrometry‐based proteomics. Besides its short serum half‐life and independence from kidney function, sBCMA represents a reliable and convenient tool for MM monitoring in patients with nonsecretory or oligosecretory disease. Numerous studies have suggested a potential utility of this bioanalyte in the risk stratification of premalignant plasma cell disorders, diagnosis and prognostication of MM, and response evaluation following anti‐myeloma therapies. In short, sBCMA might be the “Swiss army knife” of MM laboratory testing, but is it ready for prime time?

CAR-T Therapy in Multiple Myeloma: Looking Beyond

“…In MM, sBCMA could potentially function as a composite biomarker in virtually all types of MM, including non-secretory MM, due to its direct correlation to disease burden [24]. Several studies evaluating BCMA-directed molecules use sBCMA as a surrogate biomarker to evaluate responses to treatment and the duration of these responses [25]. Unfortunately, the increased expression of sBCMA can potentially reduce BCMA-directed therapy due to the binding of the molecules to sBCMA instead of the membrane-bound domain [26].…”