A Study Comparing Teclistamab Monotherapy Versus Pomalidomide, Bortezomib, Dexamethasone (PVd) or Carfilzomib, Dexamethasone (Kd) in Participants With Relapsed or Refractory Multiple Myeloma

Prior treatment

• Received any prior B cell maturation antigen (BCMA)-directed therapy
• A participant is not eligible to receive PVd as control therapy if any of the following are present: (1) Received prior pomalidomide therapy, (2) Does not meet criteria for bortezomib retreatment (3) Contraindications or life-threatening allergies, hypersensitivity, or intolerance to pomalidomide or bortezomib, (4) Grade 1 peripheral neuropathy with pain or Grade greater than or equal to (\>=) 2 peripheral neuropathy as defined by National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) Version 5.0, (5) Received a strong cytochrome P (CYP) 3A4 inducer within 5 half-lives prior to randomization; A participant is not eligible to receive Kd as control therapy if any of the following are present:(1) Received prior carfilzomib therapy, (2) Uncontrolled hypertension, defined as an average systolic blood pressure greater than (\>)159 millimeters of mercury (mmHg) or diastolic blood pressure \>99 mmHg despite optimal treatment (3) Grade 2 peripheral neuropathy with pain or Grade \>=3 peripheral neuropathy as defined by NCI-CTCAE Version 5.0, (4) Contraindications or life-threatening allergies, hypersensitivity, or intolerance to carfilzomib (intolerance defined as prior therapy discontinued due to any adverse event \[AE\] related to carfilzomib)
• Received a maximum cumulative dose of corticosteroids of \>=140 mg of prednisone or equivalent within 14 days prior to randomization
• Received a live, attenuated vaccine within 4 weeks before randomization

Other illness

• Plasma cell leukemia at the time of screening, Waldenstrom's macroglobulinemia, polyneuropathy, organomegaly, endocrinopathy, M-protein (POEMS) syndrome and skin changes, or primary amyloid light chain amyloidosis

Other

• Central nervous system (CNS) involvement or clinical signs of meningeal involvement of multiple myeloma

• Documented diagnosis of multiple myeloma as defined by the criteria below: (a)Multiple myeloma diagnosis according to International Myeloma Working Group (IMWG) diagnostic criteria (b) Measurable disease at screening as defined by any of the following: (1) Serum M-protein level greater than or equal to (\>=)0.5 grams per deciliter (g/dL) (central laboratory); or (2) Urine M-protein level \>=200 milligrams (mg)/24 hours (central laboratory); or (3) Serum immunoglobulin free light chain \>=10 milligrams per deciliter (mg/dL) (central laboratory) and abnormal serum immunoglobulin kappa lambda free light chain ratio
• Received 1 to 3 prior lines of antimyeloma therapy including a minimum of 2 consecutive cycles of an anti- cluster of differentiation 38 (CD38) monoclonal antibody at the approved dosing regimen in any prior line and 2 consecutive cycles of lenalidomide in any prior line
• Documented evidence of progressive disease or failure to achieve a response to last line of therapy based on investigator's determination of response by International myeloma working group (IMWG) criteria
• Have an Eastern Cooperative Oncology Group (ECOG) performance status score of 0 to 2
• A female participant must agree not to be pregnant, breast-feeding, or plan to become pregnant while enrolled in this study or within 6 months after the last dose of study treatment
• Must be willing and able to adhere to the lifestyle restrictions specified in this protocol