Up-front carfilzomib, lenalidomide, and dexamethasone with transplant for patients with multiple myeloma: the IFM KRd final results

Bortezomib, lenalidomide, and dexamethasone plus transplant is a standard of care for eligible patients with multiple myeloma. Because responses can deepen with time, regimens with longer and more potent induction/consolidation phases are needed. In this phase 2 study, patients received eight 28-day cycles of carfilzomib (K) 20/36 mg/m2 (days 1-2, 8-9, 15-16), lenalidomide (R) 25 mg (days 1-21), and dexamethasone (d) 20 mg (days 1-2, 8-9, 15-16, 22-23). All patients proceeded to transplant after 4 cycles and received 1 year of lenalidomide maintenance (10 mg, days 1-21). The primary objective was stringent complete response at the completion of consolidation. Overall, 48 patients were screened and 46 enrolled; 21% had adverse cytogenetics. Among 42 evaluable patients after consolidation, 26 were in stringent complete response (CR; 61.9%), 27 were at least in CR (64.3%): 92.6% had undetectable minimal residual disease according to flow cytometry (≥2.5 × 10-5) and 63.0% according to next-generation sequencing (10-6). Median time to CR was 10.6 months. According to multiparametric flow cytometry and next-generation sequencing, 69.0% and 66.7% of patients, respectively, had undetectable minimal residual disease at some point. With a median follow-up of 60.5 months, 21 patients progressed, and 10 died (7 of multiple myeloma). Median progression-free survival was 56.4 months. There were no KRd-related deaths. Four patients discontinued the program due to toxicities; 56 serious adverse events were reported in 31 patients, including 8 cardiovascular events (2 heart failures, 5 pulmonary embolisms or deep vein thrombosis). Common grade 3/4 adverse events were hematologic (74%) and infectious (22%). In summary, 8 cycles of KRd produce fast and deep responses in transplant-eligible patients with newly diagnosed multiple myeloma. The safety profile is acceptable, but cardiovascular adverse events should be closely monitored. This clinical trial is registered at www.clinicaltrials.gov as #NCT02405364.