Daratumumab-bortezomib-thalidomide-dexamethasone for newly diagnosed myeloma: CASSIOPEIA minimal residual disease results

Previous results from CASSIOPEIA demonstrated superior progression-free survival (PFS) and minimal residual disease (MRD) negativity with the addition of daratumumab to bortezomib, thalidomide, and dexamethasone (VTd) induction/consolidation and with daratumumab maintenance vs observation in transplant-eligible, newly diagnosed multiple myeloma. Here, we present long-term MRD status and PFS outcomes after a median follow-up of 80.1 months. Patients were randomly assigned (1:1) to daratumumab plus VTd (D-VTd) or VTd induction/consolidation; patients remaining on study were rerandomized to daratumumab maintenance or observation for ≤2 years. MRD status was assessed at predefined time points during each study phase. D-VTd improved overall MRD-negativity rates (10-5) after induction (34.6% vs 23.1%) and consolidation (63.7% vs 43.7%) and provided PFS benefit, regardless of postinduction MRD status, vs VTd alone. Daratumumab maintenance improved overall MRD-negativity rates over observation, regardless of induction/consolidation treatment (D-VTd/daratumumab vs D-VTd/observation, 10-5 [77.3% vs 70.7%] and 10-6 [60.7% vs 52.0%]; VTd/daratumumab vs VTd/observation, 10-5 [70.9% vs 51.2%] and 10-6 [48.4% vs 30.7%]) and improved MRD-negativity rates, regardless of risk status, as defined by cytogenetic abnormalities or the revised International Staging System score. Furthermore, daratumumab maintenance provided PFS benefit vs observation, regardless of induction/consolidation treatment and postconsolidation MRD status. D-VTd followed by daratumumab maintenance consistently produced the highest landmark, cumulative, and sustained MRD-negativity rates (10-5 and 10-6), translating to superior long-term PFS outcomes. These results demonstrate that daratumumab-based induction/consolidation followed by daratumumab maintenance resulted in the deepest and most durable MRD negativity, leading to superior PFS outcomes. This trial was registered at www.clinicaltrials.gov as #NCT02541383.