Dose/schedule-adjusted Rd-R vs continuous Rd for elderly, intermediate-fit patients with newly diagnosed multiple myeloma

Lenalidomide-dexamethasone (Rd) is standard treatment for elderly patients with multiple myeloma (MM). In this randomized phase 3 study, we investigated efficacy and feasibility of dose/schedule-adjusted Rd followed by maintenance at 10 mg per day without dexamethasone (Rd-R) vs continuous Rd in elderly, intermediate-fit newly diagnosed patients with MM. Primary end point was event-free survival (EFS), defined as progression/death from any cause, lenalidomide discontinuation, or hematologic grade 4 or nonhematologic grade 3 to 4 adverse event (AE). Of 199 evaluable patients, 101 received Rd-R and 98 continuous Rd. Median follow-up was 37 months. EFS was 10.4 vs 6.9 months (hazard ratio HR, 0.70; 95% confidence interval CI, 0.51-0.95; P = .02); median progression-free survival, 20.2 vs 18.3 months (HR, 0.78; 95% CI, 0.55-1.10; P = .16); and 3-year overall survival, 74% vs 63% (HR, 0.62; 95% CI, 0.37-1.03; P = .06) with Rd-R vs Rd, respectively. Rate of ≥1 nonhematologic grade ≥3 AE was 33% vs 43% (P = .14) in Rd-R vs Rd groups, with neutropenia (21% vs 18%), infections (10% vs 12%), and skin disorders (7% vs 3%) the most frequent; constitutional and central nervous system AEs mainly related to dexamethasone were more frequent with Rd. Lenalidomide was discontinued for AEs in 24% vs 30% and reduced in 45% vs 62% of patients receiving Rd-R vs Rd, respectively. In intermediate-fit patients, switching to reduced-dose lenalidomide maintenance without dexamethasone after 9 Rd cycles was feasible, with similar outcomes to standard continuous Rd. This trial was registered at www.clinicaltrials.gov as #NCT02215980.