• This is a multi-center, open-label, Phase 2 treatment extension study in participants with multiple myeloma who are still benefitting from isatuximab based therapy following completion of a Phase 1, 2, or 3 parental study.
• This Treatment Extension study has the purpose to provide continued access to isatuximab. Adult participants with multiple myeloma who have enrolled on an isatuximab parental study for which study objectives are completed will be eligible to be enrolled in this Treatment Extension study.
• The primary objective of the study is to assess long-term safety of isatuximab as study treatment.

Participants can continue the treatment until disease progression, unacceptable adverse events, participant wish to discontinue study treatment, study treatment is commercially available and reimbursed in participant's country, or for any other reason, whichever comes first. The overall study duration will be of approximately 42 months.

Inclusion Criteria:

• Participant must be ≥18 years of age (or the legal age of consent in the jurisdiction in which the study is taking place), at the time of signing the informed consent.
• Participants of a parental Phase 1, 2, or 3 clinical study assessing isatuximab monotherapy or in a combination regimen with all the study objectives completed.
• Participants still receiving isatuximab at the time of the parental study closure, who are continuing to benefit from isatuximab as monotherapy or in combination, as determined by the treating physician, and who meet the criteria to initiate a subsequent cycle of therapy as described in the parental study protocol. A participant not receiving isatuximab at the end of the parental study who does not have access locally to the ongoing treatment may also be included.
• Contraception (with double contraception methods) for male and female participants; not pregnant or breastfeeding for female participants; no sperm donation for male participants.
• Capable of giving signed informed consent.

Exclusion Criteria:

• Participant has evidence of progressive disease during or at the time of the parental study closure.
• Participant has not recovered to ≤Grade 2 from nonhematologic AEs (as per NCI CTCAE v5.0) related to any anticancer therapy received prior to signing informed consent on the extension study.
• As the latest line of treatment participant received an antimyeloma therapy other than the isatuximab-based therapy in the parental study before the first IMP in this study.
• Individuals accommodated in an institution because of regulatory or legal order; prisoners or participants who are legally institutionalized.
• Participant not suitable for participation, whatever the reason, as judged by the Investigator, including medical or clinical conditions, or participants potentially at risk of noncompliance to study procedures.
• Participants are employees of the clinical study site or other individuals directly involved in the conduct of the study, or immediate family members of such individuals.
• Any country-related specific regulation that would prevent the participant from entering the study.

The above information is not intended to contain all considerations relevant to a potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org