A Study to Evaluate a Novel Gene Therapy in Patients With Relapsed and Refractory Multiple Myeloma

Inclusion Criteria: * Participants must have relapsed and refractory multiple myeloma (RRMM) with measurable disease * Participants must have received at least 3 prior lines of therapy including a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and CD38-directed monoclonal antibody * Participants must have an Eastern Cooperative Group (ECOG) performance status of 0-1 * Participants must have acceptable laboratory values as defined by the protocol Exclusion Criteria: * Participants must not have known central nervous system (CNS) involvement with myeloma * Participants cannot have plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS (polyneuropathy, organomegaly, endocrinopathy, and skin changes) syndrome, or primary light chain amyloidosis * Participants cannot have ongoing acute systemic infection requiring antimicrobial therapy * Participants cannot require systemic steroids for any condition