A clinical proof-of-concept study (Clinicaltrials.gov identifier: NCT0302577) is underway to reduce the levels of γ-secretase cleaved soluble BCMA in MM patients by using a γ-secretase inhibitor, because soluble BCMA interferes with the efficacy of both BCMA-directed BiTEs and CAR-T cells [65]. This evidence concerns the gene TNFRSF17 and Miyoshi myopathy.