GPRC5D and Miyoshi myopathy: In addition to BCMA, many other investigational CAR T-cell therapies for MM are being studied, including cell products targeting SLAMF7, CD19, CD38, TACI (transmembrane activator and CAML interactor), GPRC5D (G protein-coupled receptor, class C, group 5, member D), and CD138.282,289–291 However, the application of CAR-T therapy has been limited by relapse, resistance and toxicity.292–298 Researchers have used diverse approaches to improve CAR-T therapy.