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

Inclusion Criteria: * 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 Exclusion …