Teclistamab

The proportion of participants achieving measurable residual disease negativity at a sensitivity level of 10\^-5 together with complete response, assessed according to International Myeloma Working Group (IMWG) criteria at the specified timepoint.

PFS is defined as the time from the date of randomization to the date of first documented disease progression, as defined in the International myeloma working group (IMWG) 2016 response criteria, or death due to any cause, whichever occurs first.

Severity for CRS will be graded as follows: Grade 1: Fever (Temperature greater than or equal to \[\>=\] 38°C); Grade 2: Fever (Temperature \>=38°C) with either: hypotension and/or hypoxia requiring low-flow nasal cannula or blow-by; Grade 3: Fever (Temperature \>=38°C) with either: hypotension and/or hypoxia requiring high-flow nasal cannula, facemask, nonrebreather mask, or Venturi mask; Grade 4: Fever (Temperature \>=38°C) with either: hypotension requiring multiple vasopressors (excluding vasopressin), and/or hypoxia requiring positive pressure and Grade 5: Death.

PFS is defined as the duration from the date of randomization to either progressive disease or death, whichever comes first. Disease progression will be determined according to the International Myeloma Working Group (IMWG) response criteria.

12-month MRD-negative CR is defined as participants who achieve MRD-negative status at 12 months, as determined by next-generation sequencing (NGS) with sensitivity of 10\^-5, prior to progressive disease or subsequent anti-myeloma therapy and who also achieve CR or better, according to IMWG criteria.

Heme-CR will be defined as: involved free light-chain level less than the upper limit of the normal range with negative serum and urine immunofixation; normalization of the uninvolved free light-chain level or free light-chain ratio will not be required to determine a complete response.

Percentage of participants achieving CR or better according to EHA/ISA guidelines

Evaluate the overall incidence of CRS in the first 2 cycles after a single dose of prophylactic tocilizumab given 2 to 4 hours prior to step-up dose 1 of teclistamab or talquetamab or after 3 doses of oral dexamethasone given after each step-up dose and the first full dose of teclistamab.

The complete response rate (CRR) was defined as the proportion of participants achieving complete response (CR) based on International Myeloma Working Group (IMWG) Response criteria. CR defined as requires all of the following: * Disappearance of the original monoclonal protein from the blood and urine on at least two determinations for a minimum of six weeks by immunofixation studies. * \<5% plasma cells in the bone marrow on at least two determinations for a minimum of six weeks. * No increase in the size or number of lytic bone lesions (development of a compression fracture does not exclude response). * Disappearance of soft tissue plasmacytomas for at least six weeks.

ORR is defined as the proportion of participants who have a partial response (PR) or better according to the International Myeloma Working Group (IMWG) criteria.

Cmax is defined as the maximum observed serum concentration of teclistamab (after first treatment dose).

AUCtau is defined as area under the concentration-time curve during dosing interval of teclistamab (after first treatment dose).

Ctrough is defined as observed serum concentration immediately prior to the next study treatment administration.

An AE can be any unfavorable and unintended sign (including an abnormal finding), symptom, or disease temporally associated with the use of a medicinal (investigational or non-investigational) product, whether or not related to that medicinal (investigational or non-investigational) product.

Number of participants with AEs by severity will be reported.

Number of participants with abnormalities in laboratory values (such as serum chemistry, hematology) will be reported.

The Dose Limiting Toxicities (DLTs) are based on drug related adverse events and defined as any of the following events: hematological / non hematological toxicity of Grade 3 or higher.

An AE is any untoward medical occurrence in a clinical study participant administered a pharmaceutical (investigational or non investigational) product. An AE does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal finding), symptom, or disease temporally associated with the use of a medicinal (investigational or non investigational) product, whether or not related to that medicinal (investigational or non investigational) product.

A SAE is any untoward medical occurrence that at any dose: results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability/incapacity; is a congenital anomaly/birth defect; is a suspected transmission of any infectious agent via a medicinal product; is medically important.

Number of participants with DLT will be assessed. The DLTs are specific adverse events and are defined as any of the following: high grade non-hematologic toxicity, or hematologic toxicity.

ORR is defined as the percentage of participants who have a partial response (PR) or better according to the 2016 International Myeloma Working Group (IMWG) response criteria.

The Dose Limiting Toxicities (DLTs) are based on drug related adverse events and defined as any of the following events: hematological / non hematological toxicity of Grade 3 or higher.

An AE is any untoward medical occurrence in a participant participating in a clinical study that does not necessarily have a causal relationship with the pharmaceutical/biological agent under study.