Inclusion Criteria:

          -  Documented diagnosis of multiple myeloma according to International Myeloma Working
             Group (IMWG) diagnostic criteria

          -  Measurable multiple myeloma that is relapsed or refractory to established therapies
             with known clinical benefit in relapsed/refractory multiple myeloma or be intolerant
             of those established multiple myeloma therapies, and a candidate for Teclistamab
             treatment in the opinion of the treating physician. Prior lines of therapy must
             include a proteasome inhibitor, an immunomodulatory drug and anti-CD38 monoclonal
             antibody in any order during the course of treatment. Participants who could not
             tolerate a proteasome inhibitor or immunomodulatory drugs and an anti-CD38 monoclonal
             antibody are allowed

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1

          -  Women of childbearing potential and fertile men who are sexually active must agree to
             use a highly effective method of contraception (less than [<] 1%/year failure rate)
             during the study and for 90 days after the last dose of study drug. Contraception must
             be consistent with local regulations regarding the use of birth control methods for
             participants participating in clinical trials. When a woman is of childbearing
             potential the following are required: A woman using hormonal contraceptives must use
             an additional barrier method (failure rate of <1% per year when used consistently and
             correctly). Examples of highly effective contraceptives for women include
             user-independent methods (for example, implantable progestogen-only hormone
             contraception associated with inhibition of ovulation; intrauterine device;
             intrauterine hormone-releasing system; vasectomized partner) and user-dependent
             methods (for example: combined [estrogen- and progestogen-containing] hormonal
             contraception associated with inhibition of ovulation [oral/intravaginal/
             transdermal]; progestogen-only hormone contraception associated with inhibition of
             ovulation [oral/injectable]. In addition to the highly effective method of
             contraception, a man who is sexually active with a woman of childbearing potential
             must agree to use a barrier method of contraception (for example a condom with
             spermicidal foam/gel/film/cream/suppository). Additionally, a man who is sexually
             active with a woman who is pregnant must use a condom. Women and men must agree not to
             donate eggs (ova, oocytes) or sperm, respectively, during the study and for 90 days
             after the last dose of study drug

          -  Participants must sign an informed consent form (ICF) indicating that he or she
             understands the purpose of and procedures required for the study and is willing to
             participate in the study. Consent is to be obtained prior to the initiation of any
             study-related tests or procedures that are not part of standard-of-care for the
             participant's disease

        Exclusion Criteria:

          -  Prior treatment with any B cell maturation antigen (BCMA) targeted therapy

          -  Prior antitumor therapy as follows, before the first dose of study drug: Targeted
             therapy, epigenetic therapy, or treatment with an investigational drug or used an
             invasive investigational medical device within 21 days or at least 5 half-lives,
             whichever is less; Monoclonal antibody treatment for multiple myeloma within 21 days;
             Cytotoxic therapy within 21 days; Proteasome inhibitor therapy within 14 days;
             Immunomodulatory agent therapy within 7 days; Gene modified adoptive cell therapy
             (example, chimeric antigen receptor modified T cells, natural killer [NK] cells)
             within 3 months; Radiotherapy within 14 days or focal radiation within & days

          -  Toxicities from previous anticancer therapies that have not resolved to baseline
             levels or to Grade 1 or less except for alopecia or peripheral neuropathy

          -  Received a cumulative dose of corticosteroids equivalent to >= 140 milligram (mg) of
             prednisone within the 14-day period before the first dose of study drug (does not
             include pretreatment medication)

          -  Known active central nervous system (CNS) involvement or exhibits clinical signs of
             meningeal involvement of multiple myeloma