Part A of the study will be Dose Escalation followed by Part B, an expansion cohort.~Following consent, enrolled subjects will undergo a leukapheresis procedure to collect autologous mononuclear cells for manufacture of investigational drug product (bb21217). Following manufacture of the drug product, subjects will receive lymphodepletion prior to bb21217 infusion. All subjects will then be followed for up to 60 months in Study CRB-402.~All subjects who complete the study, as well as those who withdraw from the study after receiving bb21217 for reasons other than death or meeting the early termination criteria, will be asked to continue to undergo long-term follow-up in a companion study.
Study CRB-402 is a 2-part, non-randomized, open label, multi-site Phase 1 study of bb21217 in adults with relapsed/refractory multiple myeloma (MM).