First-line therapy with either bortezomib-melphalan-prednisone or lenalidomide-dexamethasone followed by lenalidomide for transplant-ineligible multiple myeloma patients: a pooled analysis of two randomized trials.

Bortezomib-melphalan-prednisone and continuous lenalidomide-dexamethasone represent the standard treatment of transplant-ineligible, newly diagnosed, multiple myeloma patients. To date, no randomized trial has compared bortezomib-melphalan-prednisone to lenalidomide-dexamethasone, and there is no evidence of the optimal treatment for newly diagnosed multiple myeloma, particularly in high-risk cytogenetic patients (del(17p), t(4;14) or t(14;16)). We pooled together data from newly diagnosed myeloma patients treated with bortezomib-melphalan-prednisone or lenalidomide-dexamethasone induction followed by lenalidomide maintenance 10 mg enrolled in the GIMEMA-MM-03-05 and EMN01 trials, to evaluate their efficacy in different patient subgroups, focusing on standard and high-risk cytogenetics. Overall, 474 patients were analyzed (bortezomib-melphalan-prednisone: 257 patients; lenalidomide-dexamethasone followed by lenalidomide maintenance: 217 patients). No difference in progression-free survival (Hazard Ratio: 0.96) and overall survival (Hazard Ratio: 1.08) was observed between bortezomib-melphalan-prednisone and lenalidomide-dexamethasone followed by lenalidomide in standard-risk, while a reduction in the risk of progression (Hazard Ratio: 0.54) and death (Hazard Ratio: 0.73) was seen in high-risk patients treated with bortezomib-melphalan-prednisone vs. lenalidomide-dexamethasone followed by lenalidomide. In particular, standard risk patients >75years benefited less from bortezomib-melphalan-prednisone than lenalidomide-dexamethasone followed by lenalidomide (Hazard Ratio for progression-free survival: 0.96; Hazard Ratio for overall survival: 1.81). In this non-randomized analysis, bortezomib-melphalan-prednisone and lenalidomide-dexamethasone followed by lenalidomide were equally effective in younger (≤75years), standard-risk patients, while older ones (>75years) benefited more from lenalidomide-dexamethasone followed by lenalidomide. In high-risk patients, bortezomib-melphalan-prednisone improved progression-free survival and overall survival irrespective of age. The source trials are registered at ClinicalTrials.gov (NCT01063179 and NCT01093196).