A Study of Gammagard Liquid (Immune Globulin Infusion, 10%) to Prevent Infections in Adults With Multiple Myeloma

Inclusion Criteria:

1. The participants must have a documented diagnosis of Multiple Myeloma (MM) accordingto the guidelines by the International Myeloma Working Group (IMWG) beforeenrollment.

2. Participant who recently started teclistamab within the first 8 weeks of theirplanned treatment schedule and are planned to receive teclistamab for the next 12months.

3. The participant or the participant's legally acceptable representative has providedinformed consent (that is, in writing, documented via a signed and dated InformedConsent Form [ICF]) and any required privacy authorization before the initiation ofany study procedures.

4. The participant is at least 18 years of age at the time of signing the ICF.

5. If a person of childbearing potential engages in sexual relations that carry risk ofpregnancy, they agree to the following for the period from screening until 30 daysafter the last dose of study drug:

6. To use a highly effective contraceptive method.

7. To avoid donating ova.

Exclusion Criteria:

1. The participant has not achieved at least a minimal response to teclistamab within 8weeks during the screening period.

2. The participant has a current serious infection or greater than (>) 1 seriousinfection in the past 3 months before screening.

3. The participant has a documented polyclonal IgG level less than (<) 150 milligramsper deciliter (mg/dL) at the most recent assessment before teclistamab initiation (within 4 weeks) as assessed by the investigator according to the site's standardpractice.

4. The participant is currently receiving immunoglobulin products or has receivedimmunoglobulin products within 16 weeks before screening.

5. The participant has received a hyperimmune or specialty high-titer immunoglobulinproduct (example, cytomegalovirus immune globulin, varicella-zoster immune globulin,hepatitis B immune globulin) within 30 days before screening.

6. The participant has received live viral vaccines within 30 days before screening.

7. The participant has an Eastern Cooperative Oncology Group performance status scoreof >2.

8. The participant has an active viral or bacterial infection or symptoms/signs of suchan infection requiring treatment with anti-infectives within 1 week beforeenrollment.

9. The participant has received other B Cell Maturation Antigen (BCMA)*Cluster ofDifferentiation (CD3)-directed Bispecific Antibody therapy any time beforescreening.

10. The participant is scheduled to undergo plasmapheresis during the course of study orhas undergone plasmapheresis in the last 16 weeks before screening.

11. The participant may be excluded from the study if, in the opinion of theinvestigator, the participant is at high risk for symptomatic hyperviscositysyndrome.

12. The participant has major surgery scheduled during the study, or the participant hasnot fully recovered from a recent major surgery (as judged by the investigator)during screening (participants with planned surgical procedures to be conductedunder local anesthesia may participate).

13. The participant has an active secondary (non-MM) malignancy or other medicalcondition with life-expectancy of less than (<) 2 years.

14. The participant has a known history of hypersensitivity or persistent reactions (urticaria, breathing difficulty, severe hypotension, or anaphylaxis) afterIntravenous Immunoglobulin (IVIG) and/or immune serum globulin infusions.

15. The participant has a known history or current diagnosis of thromboembolic episodessuch as deep vein thrombosis, pulmonary embolism, myocardial infarction, ischemicstroke, transient ischemic attack, peripheral artery disease within 6 months beforescreening.

16. The participant has moderate to severe renal dysfunction based on an estimatedglomerular filtration rate less than or equal to (<=) 30 milliliters per minute per 1.73 square meters (mL/min/1.73 m^2), as defined by kidney disease: Improving GlobalOutcomes Clinical Practice Guideline for the Management of Glomerular Diseases, 2021at the time of screening.

17. The participant has a known history of or is positive at screening for one or moreof the following: hepatitis B surface antigen, Polymerase Chain Reaction (PCR) forhepatitis C virus, PCR for Human Immunodeficiency Virus (HIV) Type 1 and Type 2.Cured participants with a history of hepatitis C infection who have a negative PCRtest at screening are eligible.

18. The participant has a documented diagnosis of a form of primary immunodeficiency (PID) involving a defect in antibody formation and requiring IgG replacement, asdefined according to the International Union of Immunological Societies Committee.

19. The participant has a persistent serum aspartate aminotransferase and alanineaminotransferase >3.0 times the upper limit of normal at screening (may be repeatedonce to determine if it is persistent).

20. The participant has an immunoglobulin A (IgA) deficiency (<0.07 grams per liter [g/L]) with antibodies to IgA and a history of hypersensitivity reaction to IVIG.

21. Participant with a known systemic hypersensitivity to any of the excipients of IGI, 10% in accordance with the investigator's brochure/package insert/Summary of ProductCharacteristics.

22. Known substance abuse including opiates, psychostimulant agents, or other illicitdrugs with the exception of cannabinoids within 12 months of screening.

23. The participant has anemia that would preclude phlebotomy for laboratory studies,according to standard practice at the site, at the discretion of the investigator (may be repeated once to determine if it has resolved).

24. The participant has a medical condition, laboratory finding, or physical examinationfinding that precludes participation or with clinical evidence of any significantacute or chronic disease that, in the opinion of the investigator, may interferewith the successful completion of the study or place the participant at unduemedical risk.

25. The participant is receiving immunosuppressive treatment (other than for MM orcorticosteroids) at screening or plans to receive immunosuppressive treatment afterstudy enrollment.

26. The participant or the participant's legally designated representative is notwilling and able to comply with the protocol requirements.

27. The participant has participated or is scheduled to participate in another clinicalstudy involving an investigational product (IP) or investigational device within 30days before screening and during the course of the study.

28. The participant is a family member or employee of the investigator or theinvestigator's site staff.

29. The participant is pregnant or has a positive pregnancy test or is lactating at thetime of screening or enrollment.