Long-term results of the GIMEMA VEL-03-096 trial in MM patients receiving VTD consolidation after ASCT: MRD kinetics' impact on survival.

Polymerase chain reaction (PCR)-based minimal residual disease (MRD) analysis is a useful prognostic tool in multiple myeloma (MM), although its long-term impact still needs to be addressed. This report presents the updated results of the GIMEMA-VEL-03-096 trial. Thirty-nine MM patients receiving bortezomib-thalidomide-dexamethasone after autologous transplantation were monitored for MRD by both nested and real-time quantitative-PCR until relapse. Our data confirm the strong impact of MRD on survival: overall survival was 72% at 8 years median follow-up for patients in major MRD response versus 48% for those experiencing MRD persistence (P=0.041). In addition, MRD kinetics resulted predictive for relapse: indeed median remission duration was not reached for patients in major MRD response, 38 months for those experiencing MRD reappearance and 9 months for patients with MRD persistence (P<0.001). Moreover: (1) 26 patients achieving major MRD response (67%) benefit of excellent disease control (median TNT: 42 months); (2) MRD reappearance heralds relapse, with a TNT comparable to that of MRD persistence (9 versus 10 months, P=0.706); (3) the median lag between MRD reappearance and need for salvage treatment is 9 months. These results suggest the usefulness of a long-term MRD monitoring in MM patients and the need for maintenance or pre-emptive treatments ensuring durable responses.