A Study of JNJ-79635322 in Participants With Relapsed or Refractory Multiple Myeloma or Previously Treated Amyloid Light-chain (AL) Amyloidosis

Exclusion Criteria23

• For participants with relapsed or refractory multiple myeloma:
• Central Nervous System (CNS) involvement or clinical signs of meningeal involvement of multiple myeloma. If either is suspected, brain magnetic resonance imaging (MRI) and lumbar cytology are required
• Active plasma cell leukemia, Waldenstrom's macroglobulinemia, POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes), or primary light chain amyloidosis
• Received a cumulative dose of corticosteroids equivalent to greater than (\>) 140 mg of prednisone within the 14-day period before the start of study treatment administration
• Prior antitumor therapy as follows, in the specified time frame prior to the first dose of study treatment: (proteasome inhibitor \[PI\] therapy or radiotherapy within 14 days, immunomodulatory drug (IMiD) agent therapy within 7 days, gene-modified adoptive cell therapy within 90 days \[not applicable for Part 2C participants\], or CD3-redirecting therapy within 21 days\[not applicable for Part 2B or 2C participants\])
• Prior allogeneic transplant within 6 months before the start of study treatment administration or autologous transplant within 12 weeks before the start of study treatment administration
• Live, attenuated vaccine within 4 weeks before the first dose of study treatment
• Non-hematologic toxicity from prior anticancer therapy that has not resolved to baseline levels or to Grade less than or equal to (\<=) 1 (except alopecia, tissue post-RT fibrosis \[any grade\] or peripheral neuropathy to Grade \<=3)
• The following medical conditions: pulmonary compromise requiring supplemental oxygen use to maintain adequate oxygenation, human immunodeficiency (HIV) infection, active hepatitis B or C infection, stroke or seizure within 6 months prior to first dose of study treatment, autoimmune disease, serious active viral or bacterial infection, uncontrolled systemic fungal infection, cardiac conditions (myocardial infarction \<=6 months prior to enrollment, New York Heart Association stage III or IV congestive heart failure, et cetera)
• Part 2C: have progressive disease or refractory disease per IMWG after CAR-T administration
• For participants with previously treated AL amyloidosis:
• CNS involvement or clinical signs of meningeal involvement of AL amyloidosis. If either is suspected, whole brain MRI and lumbar cytology are required
• Any form of non-AL amyloidosis, including but not limited to transthyretin (ATTR) amyloidosis
• Active plasma cell leukemia, Waldenstrom's macroglobulinemia, or POEMS syndrome
• Pulmonary compromise requiring supplemental oxygen use
• Any serious medical conditions such as: active viral, bacterial, fungal infection; active autoimmune disease; HIV infection, active hepatitis B or C infection, stroke or seizure within 6 months prior to first dose of study treatment, significant cardiovascular conditions
• Previous or current diagnosis of symptomatic multiple myeloma
• Macroglossia that impairs swallowing difficulty
• Received a cumulative dose of corticosteroids equivalent to \> 140 mg of prednisone within the 14-day period before the start of study treatment administration
• Prior antitumor therapy within 21 days prior to the first dose of study treatment (PI therapy or radiotherapy within 14 days, IMiD agent therapy within 7 days, gene-modified adoptive cell therapy within 90 days, or CD3-redirecting therapy within 21 days)
• Prior allogeneic transplant within 6 months before the start of study treatment administration or autologous transplant within 12 weeks before the start of study treatment administration
• Live, attenuated vaccine within 4 weeks before the first dose of study treatment
• Non-hematologic toxicity from prior anticancer therapy that has not resolved to baseline levels or to \<=1 (except alopecia, tissue post-RT fibrosis \[any grade\] or peripheral neuropathy to Grade \<=3)