A Multicenter, Randomized, Controlled, Open-label, Group-Sequential, Phase 3 Study to Investigate the Efficacy, Safety, and Tolerability of Intravenous Gammagard Liquid (Immune Globulin Infusion, 10%) for Primary Infection Prophylaxis Compared With Secondary Infection Prophylaxis in Adult Subjects With Multiple Myeloma Receiving B-Cell Maturation AntigenxCD3-Directed Bispecific Antibody Therapy
Multiple myeloma is a cancer of the plasma cells in the bone marrow. The main aim of this study is to learn how well the Immune Globulin Infusion (human), 10 percentage (%) (IGI, 10%) can help prevent infections in participants with multiple myeloma receiving B-cell maturation antigen (BCMA) x cluster of differentiation 3 (CD3) directed bispecific antibody therapy. Participants will be randomly assigned to one of two groups: 1. Primary infection prevention group: They will receive IGI, 10% for 12 months. 2. Secondary infection prevention group: They will only receive IGI, 10% if they develop a serious infection during the 12 months study period. During the study, participants will visit their study clinic 15 times (for 4-week dosing interval) or 19 times (for 3-week dosing interval) and their total participation duration will be up to 14 months (including screening period of up to 8 weeks).
• The participants must have a documented diagnosis of Multiple Myeloma (MM) according to the guidelines by the International Myeloma Working Group (IMWG) before enrollment.
• Participant who recently started teclistamab within the first 8 weeks of their planned treatment schedule and are planned to receive teclistamab for the next 12 months.
• The participant or the participant's legally acceptable representative has provided informed consent (that is, in writing, documented via a signed and dated Informed Consent Form \[ICF\]) and any required privacy authorization before the initiation of any study procedures.
• The participant is at least 18 years of age at the time of signing the ICF.
• If a person of childbearing potential engages in sexual relations that carry risk of pregnancy, they agree to the following for the period from screening until 30 days after the last dose of study drug:
‣ To use a highly effective contraceptive method.
⁃ To avoid donating ova.