Isatuximab, bortezomib, lenalidomide, and dexamethasone for multiple myeloma: dynamics of MRD negativity in the IMROZ study.

abstractQuadruplet therapy with Isa-VRd (isatuximab, Velcade [bortezomib], Revlimid [lenalidomide], and dexamethasone) followed by Isa-Rd in the randomized phase 3 IMROZ study provided a significant progression-free survival benefit to transplant-ineligible patients with newly diagnosed multiple myeloma (NDMM). In the primary analysis, more Isa-VRd/Isa-Rd-treated patients achieved minimal residual disease (MRD) negativity and MRD-negative complete response (CR) at any time point than patients receiving VRd followed by Rd. Here, we report landmark analysis results of MRD negativity over time and its impact on clinical outcomes in IMROZ. Treatment with Isa-VRd/Isa-Rd led to deeper responses, with higher rates of MRD negativity and MRD-negative CR at the end of induction and during maintenance vs VRd/Rd, up to 60 months of follow-up. Benefit with Isa-VRd/Isa-Rd was observed across key patient subgroups, including older (>70 years) and frail patients. Time to progression (TTP) was significantly prolonged with Isa-VRd/Isa-Rd vs VRd/Rd in patients who converted from MRD negative to MRD positive at any time point. In a landmark analysis of the time of conversion to MRD positivity, TTP in patients who converted from MRD negative at the end of induction to MRD positive also favored Isa-VRd/Isa-Rd. Evaluating MRD status of patients at >1 time point may therefore be useful to support decisions on treatment selection and treatment continuation/discontinuation. Our findings on the degree of MRD negativity and MRD-negative CR benefit achieved during induction and maintenance by patients receiving Isa-VRd/Isa-Rd vs VRd/Rd extend the IMROZ primary analyses and further support Isa-VRd as standard of care for frontline treatment of transplant-ineligible patients with NDMM. This trial was registered at www.clinicaltrials.gov as #NCT03319667.