Inclusion Criteria:

1. ≥18 years of age at the time of consent.
2. ECOG performance status of 0 or 1.
3. Documented diagnosis of MM per IMWG diagnostic criteria.
4. Participant must have received at least 3 prior lines of therapy, which include a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and an anti-CD38 antibody.
5. Have documented evidence of progressive disease per IMWG criteria.
6. Participant must have measurable disease at screening.
7. Participant must have adequate bone marrow and organ function (hematological, hepatic and renal) demonstrated at screening.

Exclusion Criteria :

1. Participant has a history of significant toxicity during prior CAR T-cell therapy and T-cell engaging therapy.
2. Participant has a history of a prior non-hematologic malignancy, unless the participant has been disease-free with no evidence of recurrence for ≥ 2 years. Some exceptions may apply.
3. Participant has significant cardiac, neurological, or psychiatric conditions.
4. Any other significant medical conditions such as:

1. Serious active or uncontrolled infection
2. Active autoimmune disease or a history of autoimmune disease within 2 years
3. Active plasma cell leukemia at the time of screening
4. Clinical evidence of dementia or altered mental status, or stroke, intracranial haemorrhage, or seizure within 6 months before signing informed consent form (ICF).
5. Known active or prior history of central nervous system involvement or exhibits clinical signs of meningeal involvement of MM.

Other protocol-defined Inclusion/Exclusion criteria apply.