A Study of JNJ-87562761 in Participants With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria:

• Relapsed, refractory multiple myeloma with measurable disease defined as: (a) Serummonoclonal paraprotein (M-protein) level greater than (>)0.5 grams per deciliter (g/dL); or (b) Urine M-protein level >200 milligrams per 24 hours (mg/24 hours); or (c) Light chain multiple myeloma: serum immunoglobulin free light chain (FLC) >10milligrams per deciliter (mg/dL) and abnormal serum immunoglobulin kappa-lambda FLCratio

• Must have had prior therapy including a proteasome inhibitor, immunomodulatory agentand anti-CD38 therapy

• Have an eastern cooperative oncology group (ECOG) performance status of 0 to 1

• Have an estimated glomerular filtration rate (eGFR), of > 30 millilitres (mL)/min/1.73 meter square (m^2) computed with the online calculator on the chronickidney disease epidemiology collaboration (CKD-EPI) by use of the CKD-EPI serumcreatinine (cr) result

• While on study treatment and for 6 months after the last dose of study treatment, aparticipant must: (a) Not breastfeed or be pregnant; (b) Not donate gametes (thatis, eggs or sperm) or freeze for future use for the purposes of assistedreproduction; (c) Wear an external condom

Exclusion Criteria:

• Active plasma cell leukemia, Waldenström's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes), orimmunoglobulin light chain amyloidosis

• Prior allogeneic transplant within 6 months before the start of study treatmentadministration or autologous transplant within 12 weeks before the start of studytreatment administration

• Live, attenuated vaccine within 4 weeks before the first dose of study treatment

• Central Nervous System (CNS) involvement or clinical signs of meningeal involvementof multiple myeloma. If either is suspected, brain magnetic resonance imaging (MRI)and lumbar cytology are required

• Non-hematologic toxicity from prior anticancer therapy that has not resolved tobaseline level or to less than or equal to (<=) Grade 1 (except alopecia, tissuepost-RT fibrosis, or Grade < 3 peripheral neuropathy)

• Received a cumulative dose of corticosteroids equivalent to greater than (>) 140 mgof prednisone within the 14-day period before the start of study treatmentadministration

• Prior antitumor therapy in the specified time frame prior to the first dose of studytreatment: (Targeted therapy, epigenetic therapy, monoclonal antibody treatment, ortreatment with an investigational drug or an invasive investigational medical deviceor conventional chemotherapy within 21 days, gene-modified adoptive cell therapy ortreatment with anti-CD38 directed therapies within 3 months, proteasome inhibitor [PI] therapy or radiotherapy within 14 days, or immunomodulatory drug (IMiD) agenttherapy within 7 days)

• Following medical conditions: pulmonary compromise requiring supplemental oxygen useto maintain adequate oxygenation, human immunodeficiency (HIV) infection (participants with a detectable viral load or low CD4 count), active hepatitis B orC infection, active autoimmune disease requiring systemic immunosuppressive therapywithin 6 months before start of study treatment, serious uncontrolled ongoing viralor bacterial or systemic fungal infection, cardiac conditions (myocardial infarction <=6 months prior to enrollment, New York Heart Association stage III or IVcongestive heart failure, et cetera [etc.] )