A Study of Ciltacabtagene Autoleucel and Talquetamab for the Treatment of Participants With High-Risk Multiple Myeloma

The purpose of this study is to define the safety of Ciltacabtagene Autoleucel (Cilta-cel) and Talquetamab in participants with high-risk multiple myeloma (MM).

Inclusion Criteria: * Documented diagnosis of MM according to the IMWG diagnostic criteria and is defined as a measurable disease at screening * Cohort 1: Received at least 3 prior lines of antimyeloma therapy and have undergone greater than or equal to (\>=) 1 complete cycle of the therapy * Cohort 1: Documented evidence of progression of disease (PD) or failure to achieve a response to the last line of therapy * Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1 * Participant of childbearing potential (POCBP) must have a negative pregnancy test using a highly sensitive β-human chorionic gonadotropin (hCG) serum pregnancy test at screening Exclusion Criteria: * Cohort 1: Prior treatment with chimeric antigen receptor T cell (CAR-T) therapy directed at any target or any prior B cell maturation antigen (BCMA)-directed therapy/prior G protein-coupled receptor family C Group 5 member D (GPRC5D)-directed therapy * Cohort 1: Received either of the following: An allogenic stem cell transplant within 6 months before apheresis/first dose of study drug and no immunosuppressive medications administered before the start of study treatment. And secondly, received an autologous stem cell transplant less than (\<)12 weeks before apheresis/first dose of study treatment * Receive live, attenuated vaccine within 4 weeks of enrollment * Toxicity from previous anticancer therapy not resolved to baseline levels or to Grade 1 or less except for alopecia or peripheral neuropathy * Stroke, transient ischemic attack, or seizure within 6 months of signing informed consent form