{"entity":{"id":"gprc5d-expression","kind":"biomarker","name":"GPRC5D expression","aka":["GPRC5D","GPRC5D-positive","GPRC5D expression myeloma"],"tldr":"GPRC5D is a receptor on myeloma cells and in hair follicles, nails and taste buds. Talquetamab targets it without any test, and the side effects on skin, nails and taste follow from where it is expressed.","summary":"Talquetamab (Talvey) is a GPRC5D x CD3 bispecific labelled for relapsed or refractory multiple myeloma after at least four prior lines; the label names GPRC5D only as the target. Expression on plasma cells is high and independent of BCMA, which is why GPRC5D-directed therapy works after BCMA failure; GPRC5D loss at relapse has been described.","asOf":"2026-09-23","links":[{"label":"TALVEY prescribing information (DailyMed)","url":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9001355e-003d-4d4e-b4ce-337e0fd14952"}],"tags":["biomarker","surface-antigen","no-threshold"],"related":["bcma-expression","fcrh5-expression"],"cancers":["multiple-myeloma","myeloma-relapsed-refractory"],"sections":[],"technologies":[],"targets":[],"drugs":["talquetamab"],"companies":[],"institutions":[],"pathways":[],"terms":["antigen-escape"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"target":"gprc5d","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":"TALVEY is a bispecific GPRC5D-directed CD3 T-cell engager","source":"https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9001355e-003d-4d4e-b4ce-337e0fd14952","sourceLabel":"TALVEY prescribing information (DailyMed)"},"thresholds":[],"tests":[],"assays":[],"companionDiagnostics":[],"forPatient":"Talquetamab is given without a GPRC5D test. Because the same receptor sits in your skin, nails and taste buds, changes in taste, dry mouth, rash and nail problems are expected and are managed rather than treated as a sign the drug is not working."},"route":"/biomarkers/gprc5d-expression/","neighbours":{"biomarker":[{"id":"bcma-expression","kind":"biomarker","name":"BCMA expression","route":"/biomarkers/bcma-expression/"},{"id":"cd38-expression","kind":"biomarker","name":"CD38 expression","route":"/biomarkers/cd38-expression/"},{"id":"fcrh5-expression","kind":"biomarker","name":"FcRH5 expression","route":"/biomarkers/fcrh5-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":"talquetamab","kind":"drug","name":"Talquetamab","route":"/drugs/talquetamab/"}],"term":[{"id":"antigen-escape","kind":"term","name":"Antigen escape (antigen loss, lineage switch)","route":"/terms/antigen-escape/"}],"target":[{"id":"gprc5d","kind":"target","name":"GPRC5D","route":"/targets/gprc5d/"}]}}