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

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 (<=) 12 months after treatment with autologous stem cell transplantation (ASCT) or <=12 months from the start of anti-myeloma therapy for participants who have not had an ASCT
Cohort C: Previously treated with a PI, an IMiD, an anti-CD38 monoclonal antibody and B-cell maturation antigen (BCMA)-directed therapy
Cohort D: Newly diagnosed multiple myeloma per IMWG with a history of 4 to 8 total cycles of initial therapy, including induction, high-dose therapy, and ASCT with or without consolidation
Cohort E: Have newly diagnosed multiple myeloma without prior therapy (one cycle of prior therapy before enrollment is acceptable) and classified as high risk defined as either: 1) International Staging System (ISS) stage III criteria, Beta 2 microglobulin greater than or equal to (>=) 5.5 milligrams per liter (mg/L) (via local or central laboratory assessment) or 2) high risk cytogenetic features del(17/17p), t (14;16), t(14;20), 1q amplification (at least 4 total copies) in at least 20 percent (%) of the total plasma cell population
Cohort F:
Participant must have a documented efficacy response of very good partial response (VGPR) or better, without progressive disease prior to enrollment, as assessed per IMWG 2016 criteria
Received initial therapy as specified below. The dose/schedule of cycles administered will be as per standard of care. It is acceptable for up to 1 cycle of the protocol-specified regimens to be missing one of the listed agents (example, held due to toxicity). Acceptable combinations include: At least 5 to 8 cycles of initial therapy with daratumumab, bortezomib, lenalidomide and dexamethasone (D-VRd). The dose/schedule of cycles administered will be as per standard of care or; at least 4 to 8 cycles of initial therapy with daratumumab, lenalidomide and dexamethasone (D-Rd) or; at least 4 to 8 cycles of initial therapy with a carfilzomib-based triplet or quadruplet regimen
Cohort G: Not considered for high-dose chemotherapy with autologous stem cell transplantation (ASCT) due to: a) Ineligibility due to advanced age; or b) Ineligibility due to presence of comorbid condition(s) likely to have a negative impact on tolerability of high-dose chemotherapy with ASCT; or c) Subject refusal of high-dose chemotherapy with ASCT as initial treatment
Cohort H: Considered a candidate for high-dose chemotherapy with ASCT as initial treatment
Cohorts A, B, C, E, G, H:
Serum monoclonal paraprotein (M-protein) level greater 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, G, H: 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
Cohorts F, G, and H: 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
Cohorts E, G, and H: Frailty index of >= 2 according to Myeloma Geriatric Assessment score