A Study of JNJ-68284528, a Chimeric Antigen Receptor T Cell (CAR-T) Therapy Directed Against B-cell Maturation Antigen (BCMA) in Participants With Multiple Myeloma

The purpose of this study is to evaluate the overall minimal residual disease (MRD) negative rate of participants who receive JNJ-68284528.

Inclusion Criteria: * Cohort A: Received a minimum of 1 to a maximum of 3 prior lines of therapy including a proteasome inhibitor (PI) and immunomodulatory therapy (IMiD), and lenalidomide refractory per International Myeloma Working Group (IMWG) guidelines * Cohort B: Received one line of prior therapy including a PI and an IMiD, and disease progression per IMWG criteria less than or equal to (\=) 1.0 gram per deciliter (g/dL) or urine M-protein level \>=200 milligrams (mg)/24 hours * Light chain multiple myeloma in whom only measurable disease is by serum free light chain (FLC) levels in the serum: Serum immunoglobulin FLC \>=10 mg/dL and abnormal serum immunoglobulin kappa lambda FLC ratio * Cohort A: For participants with neither serum nor urine measurable disease, baseline positron emission tomography/ computed tomography (PET/CT) or whole -body magnetic resonance imaging (MRI) may be used to satisfy the measurable disease criteria. A minimum of one lesion with a bi-dimensional measurement of at least 1 centimeter (cm)\*1 cm is required * Cohorts B, C: For participants with neither serum nor urine measurable disease, baseline positron emission tomography/ computed tomography (PET/CT) or whole body magnetic resonance imaging (MRI) may be used to satisfy the measurable disease criteria * Cohorts A, B, C, D, E, F and Cohort G (for US sites only): Eastern Cooperative Oncology Group (ECOG) performance status grade of 0 or 1 Exclusion Criteria: * Cohorts A, B, D, F: Any therapy that is targeted to BCMA * Cohorts A, B, C, D, F: Prior treatment with chimeric antigen receptor T (CAR-T) therapy directed at any target * Cohorts A, B, C, D, F: * Ongoing toxicity from previous anticancer therapy must resolve to baseline levels or to Grade 1 or less except for alopecia or peripheral neuropathy * Received a cumulative dose of corticosteroids equivalent to \>=70 mg of prednisone within the 7 days (Cohort A, B, C, F) or 14 days (Cohort D) prior to apheresis * Serious underlying medical condition, such as (a) evidence of active viral or bacterial infection requiring systemic antimicrobial therapy, or uncontrolled systemic fungal infection; (b) active autoimmune disease or a history of autoimmune disease within 3 years; (c) overt clinical evidence of dementia or altered mental status; (d) any history of Parkinson's disease or other neurodegenerative disorder * Cohorts A, B, C, D, E, F: Known active, or prior history of central nervous system (CNS) involvement or exhibits clinical signs of meningeal involvement of multiple myeloma * Cohort F and Cohort G (for US sites only): Active malignancies (that is, progressing or requiring treatment change in the last 24 months) other than the disease being treated under study. The only allowed exceptions are: a) non-muscle invasive bladder cancer treated within the last 24 months that is considered completely cured; b) skin cancer (non-melanoma or melanoma) treated within the last 24 months that is considered completely cured; c) non-invasive cervical cancer treated within the last 24 months that is considered completely cured; d) localized prostate cancer (N0M0): with a Gleason score of greater than or equal to (=\>)6, treated within the last 24 months or untreated and under surveillance, with a Gleason score of 3+4 that has been treated more than 6 months prior to full study screening and considered to have a very low risk of recurrence, or history of localized prostate cancer and receiving androgen deprivation therapy and considered to have a very low risk of recurrence, e) breast cancer: adequately treated lobular carcinoma in situ or ductal carcinoma in situ, or history of localized breast cancer and receiving antihormonal agents and considered to have a very low risk of recurrence; f) malignancy that is considered cured with minimal risk of recurrence * Cohort E and Cohort G (for US sites only): Frailty index of \>= 2 according to Myeloma Geriatric Assessment score