HEME-18

This is a phase II study where patients will undergo isatuximab and lenalidomide-based maintenance if they are MRD-positive after ASCT. Patients may have received equal to or less than 2 lines of induction therapy prior to ASCT. Patients will be enrolled at any time prior to ASCT or up to day 180 after ASCT.Patients will undergo disease reassessment per standard of care including BM examination and MRD testing by NGS at day 90 (+/- 30 days) of ASCT. All patients in MRD-negative (defined as 10-5) CR will be treated off study with lenalidomide monotherapy and all patients who are MRD-positive will begin treatment with isatuximab and lenalidomide, starting any time after MRD results are obtained (treatment must commence before day 180 of ASCT).Patients will be monitored for disease response and every 12 months for BM MRD status, for a total of 3 years, or until disease progression or unacceptable toxicity meeting criteria for protocol removal.