Pomalidomide will be administered orally.

Bortezomib will be administered subcutaneously.

Dexamethasone will be administered orally in PVd and intravenously or orally in Kd.

Carfilzomib will be administered intravenously.

CR or better response is defined as participants who achieve a CR or better response prior to subsequent antimyeloma therapy in accordance with the IMWG 2016 criteria.

DOR is defined as the time interval between the date of initial documentation of a response (PR or better) to the date of first documented evidence of progressive disease according to the IMWG 2016 response criteria or death due to any cause, whichever occurs first.

TTNT is defined as the time from randomization to the start of subsequent antimyeloma treatment.

PFS2 is defined as the time interval between the date of randomization and date of event, which is defined as progressive disease as assessed by investigator on the first subsequent line of antimyeloma therapy, or death from any cause, whichever occurs first.

OS is defined as the time from the date of randomization to the date of the participant's death due to any cause.

Number of participants with AEs by Severity will be reported.

Number of participants with SAEs by Severity will be reported.

Number of participants with abnormal laboratory results (such as hematology and chemistry) will be reported.

Serum concentrations of teclistamab will be reported.

Number of participants with ADAs to teclistamab will be reported.

Change from baseline in symptoms, functioning, and overall HRQoL assessed by EORTC QLQ-C30 score version 3 will be reported. The EORTC- QLQ-C30 Version 3 includes 30 items that make up 5 functional scales (physical, role, emotional, cognitive, and social), 1 global health status scale, 3 symptom scales (pain, fatigue, and nausea/vomiting), and 6 single symptom items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). The item and scale scores are transformed to a 0 to 100 scale. A high scale score represents a higher response level. Thus, a high score for a functional scale represents a high/healthy level of functioning and a high score for the global health status represents high HRQoL, but a high score for a symptom scale/item represents a high level of symptomatology/problems.

Change from baseline in symptoms, functioning, and overall HRQoL assessed by MySIm-Q will be reported. The MySIm-Q is a disease-specific PRO assessment complementary to the EORTC-QLQ-C30. It includes 17 items resulting in a symptom subscale and an impact subscale. The recall period is the "past 7 days", and responses are reported on a 5-point verbal rating scale.

Change from baseline in symptoms, functioning, and overall HRQoL assessed by PRO-CTCAE will be reported. The National Cancer Institute's (NCI's) PRO-CTCAE is an item library of common adverse events experienced by people with cancer that are appropriate for self-reporting of treatment tolerability. Each symptom selected for inclusion can be rated by up to 3 attributes characterizing the presence/frequency, severity, and/or interference of the AEs. It ranges from 0 to 4 with higher scores indicating higher frequency or greater severity/impact.

Change from baseline in symptoms, functioning, and overall HRQoL assessed by EQ-5D-5L will be reported. The EQ-5D-5L is a generic measure of health status. The EQ-5D-5L is a 5-item questionnaire that assesses 5 domains including mobility, self-care, usual activities, pain/discomfort, and anxiety/depression plus a visual analog scale rating "health today" with anchors ranging from 0 (worst imaginable health state) to 100 (best imaginable health state).

Time to worsening in symptoms, functioning, and overall HRQoL will be measured as the interval from the date of randomization to the start date of meaningful change.

PFS in participants in high-risk molecular features will be reported. PFS is defined as the time from the date of randomization to the date of first documented disease progression, as defined in the IMWG 2016 response criteria, or death due to any cause, whichever occurs first.

Depth of response in participants in high-risk molecular features will be reported.