Isatuximab in Combination With Lenalidomide and Dexamethasone in High-risk Smoldering Multiple Myeloma

Primary Objectives: * Safety run-in Part: To confirm the recommended dose of isatuximab when combined with lenalidomide and dexamethasone in participants with high-risk smoldering multiple myeloma (SMM) * Randomized Phase 3 Part: To demonstrate the clinical benefit of isatuximab in combination with lenalidomide and dexamethasone in the prolongation of progression-free survival when compared to lenalidomide and dexamethasone in subjects with high-risk SMM Secondary Objectives: Safety run-in Part: * To assess overall response rate (ORR) * To assess duration of response (DOR) * To assess minimal residual disease (MRD) negativity in participants achieving very good partial response (VGPR) or complete response (CR) * To assess time to diagnostic (SLiM CRAB) progression or death * To assess time to first-line treatment for multiple myeloma (MM) * To assess the potential immunogenicity of isatuximab * Impact of abnormal chromosomal subtype on participant outcome Randomized Phase 3 Part: Key Secondary Objectives: To compare between the arms * MRD negativity * Sustained MRD negativity * Second progression-free survival (PFS2) * Overall survival Other Secondary Objectives: To evaluate in both arms * CR rate * ORR * DOR * Time to diagnostic (SLiM CRAB) progression * Time to biochemical progression * Time to first-line treatment for MM * Impact of abnormal chromosomal subtype on participant outcome * Safety and tolerability * Pharmacokinetics (PK) * Potential of isatuximab immunogenicity * Clinical outcome assessments (COAs)