CD38 and cancer: The rationale is supported by (a) CAR T cell therapies in MM are approved for the treatment of multi-relapsing patients of which the majority have progressed after anti-CD38 based therapies; (b) CD38 remains targetable on the surface of cancer cells in multi-relapsing MM patients [12] and continued clinical targeting of CD38 can further increase the therapeutic options and survival of Dara treated patients.