{"entity":{"id":"bcma-expression","kind":"biomarker","name":"BCMA expression","aka":["BCMA","BCMA-positive","B-cell maturation antigen expression","TNFRSF17 expression","soluble BCMA"],"tldr":"BCMA is the plasma-cell antigen behind the myeloma bispecifics and CAR-T cells. None of their labels requires a BCMA test; expression is near-universal, and loss through BCMA gene deletion is a documented escape route.","summary":"Teclistamab, elranatamab and linvoseltamab (BCMA x CD3 bispecifics), idecabtagene vicleucel and ciltacabtagene autoleucel (BCMA CAR-T) and belantamab mafodotin (BCMA ADC) are labelled for relapsed or refractory multiple myeloma by prior lines of therapy, with BCMA named in the mechanism of action only. Biallelic TNFRSF17 loss and extracellular-domain mutations after BCMA-directed therapy are reported in the literature and motivate GPRC5D- and FcRH5-directed alternatives.","asOf":"2026-09-23","links":[{"label":"TECVAYLI prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=54e0f974-ccee-44ea-9254-40e9883cee1e"}],"tags":["biomarker","surface-antigen","no-threshold"],"related":["gprc5d-expression","fcrh5-expression","cd38-expression"],"cancers":["multiple-myeloma","myeloma-relapsed-refractory"],"sections":[],"technologies":[],"targets":[],"drugs":["teclistamab","elranatamab","linvoseltamab","idecabtagene-vicleucel","ciltacabtagene-autoleucel","belantamab-mafodotin"],"companies":[],"institutions":[],"pathways":[],"terms":["antigen-escape"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"bcma","measurement":"ihc-score","scoringRule":{"text":"The label names the antigen in the drug's description but does not require it to be measured before treatment; no approval threshold exists for this readout.","quote":"TECVAYLI is a bispecific B-cell maturation antigen (BCMA)-directed CD3 T-cell engager","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=54e0f974-ccee-44ea-9254-40e9883cee1e","sourceLabel":"TECVAYLI prescribing information (DailyMed)"},"thresholds":[],"tests":[],"assays":[],"companionDiagnostics":[],"forPatient":"No BCMA test is needed before a BCMA bispecific or CAR-T; the antigen is assumed. If myeloma returns after one BCMA-directed treatment, your team may test whether BCMA is still present before choosing another, or move to a drug aimed at GPRC5D."},"route":"/biomarkers/bcma-expression/","neighbours":{"biomarker":[{"id":"cd38-expression","kind":"biomarker","name":"CD38 expression","route":"/biomarkers/cd38-expression/"},{"id":"fcrh5-expression","kind":"biomarker","name":"FcRH5 expression","route":"/biomarkers/fcrh5-expression/"},{"id":"gprc5d-expression","kind":"biomarker","name":"GPRC5D expression","route":"/biomarkers/gprc5d-expression/"}],"cancer":[{"id":"multiple-myeloma","kind":"cancer","name":"Multiple myeloma","route":"/cancers/multiple-myeloma/"},{"id":"myeloma-relapsed-refractory","kind":"cancer","name":"Relapsed or refractory multiple myeloma","route":"/cancers/myeloma-relapsed-refractory/"}],"drug":[{"id":"belantamab-mafodotin","kind":"drug","name":"Belantamab mafodotin","route":"/drugs/belantamab-mafodotin/"},{"id":"ciltacabtagene-autoleucel","kind":"drug","name":"Ciltacabtagene autoleucel","route":"/drugs/ciltacabtagene-autoleucel/"},{"id":"elranatamab","kind":"drug","name":"Elranatamab","route":"/drugs/elranatamab/"},{"id":"idecabtagene-vicleucel","kind":"drug","name":"Idecabtagene vicleucel","route":"/drugs/idecabtagene-vicleucel/"},{"id":"linvoseltamab","kind":"drug","name":"Linvoseltamab","route":"/drugs/linvoseltamab/"},{"id":"teclistamab","kind":"drug","name":"Teclistamab","route":"/drugs/teclistamab/"}],"term":[{"id":"antigen-escape","kind":"term","name":"Antigen escape (antigen loss, lineage switch)","route":"/terms/antigen-escape/"}],"target":[{"id":"bcma","kind":"target","name":"BCMA","route":"/targets/bcma/"}]}}