Efficacy and safety of GPRC5D-based monotherapies for relapsed/refractory multiple myeloma: A systematic review and meta-analysis.

Abstract

e19503 Background: G protein-coupled receptor family C group 5 member D (GPRC5D), a highly expressed receptor in myeloma cells, is one of the novel emerging targets for relapsed/ refractory (R/R) multiple myeloma (MM). Among the GRPC5D therapies, currently one agent talquetamab has been approved while CAR-T therapies are under development. Methods: A literature search using electronic databases Pubmed, Embase, Scopus, Web of Science and Cochrane, including major conference abstracts was conducted from inception to December 31, 2023 focusing on GPRC5D therapies in MM. For multiple reports of the same study, the latest available report of the study describing the efficacy or safety was selected. Only GPRC5D based monotherapies were included, and combination regimens were excluded for this review. Data on safety and efficacy were extracted, evaluated and systematically analyzed using Comprehensive Meta-analysis 3.3. The study protocol was registered with PROSPERO (CRD42024497933). Results: After screening 562 articles, and removing duplicates, total seven studies with 581 patients were included (5 GPRC5D-CAR T studies with 137 patients and 2 GPRC5D-BsAb studies with 444 patients). The pooled overall response rate (ORR) for GRPC5D therapies in this cohort was 77.4%, with best response rate [very good partial response (VGPR) or better] of 59.2%. The pooled incidence rate of cytokine release syndrome (CRS), any grade and Immune effector cell-associated neurotoxicity syndrome (ICANS), any grade, was 78.8% and 9.6% respectively. Grade 3/4 hematological adverse events included neutropenia being the most common (69.6%), followed by thrombocytopenia (36.8%) and anemia (34.2 %). Subgroup analysis was performed for GPRC5D therapies- CAR T and BsAb as shown in the table. Conclusions: GPRC5D based therapies showed high response rates in R/R MM with distinct side effect profile including CRS and cytopenias. Further studies along with follow up of the ongoing trials is needed to understand the long-term outcomes. [Table: see text]