Alternating bortezomib-dexamethasone and lenalidomide-dexamethasone in patients with newly diagnosed multiple myeloma aged over 75 years.

More than 40% of Japanese patients with multiple myeloma (MM) are over 75 years of age at diagnosis. Regardless of the treatment benefits, complications and relapses obstruct long-term survival. We conducted a phase II, open-label, single-arm, multicenter clinical trial to assess the efficacy and safety of alternating bortezomib-dexamethasone (Bd) and lenalidomide-dexamethasone (Ld) (Bd/Ld) treatment in MM patients aged over 75 years (MARBLE trial). Patients received Bd therapy from days 1 to 35 and Ld therapy from days 36 to 63. For Bd therapy, patients were administered bortezomib 1.3 mg/m2 and oral dexamethasone 20 mg on days 1, 8, 15, and 22. For Ld therapy, they were administered lenalidomide 15 mg from days 36 to 56 and dexamethasone 10 mg on days 36, 43, 50, and 57. They underwent six treatment cycles in total, each consisting of a 63-day regimen. In total, 10 patients were enrolled, with a median age of 81 years. Efficacy was not evaluated because the patients were fewer than planned. The overall response rate was 80.0% and complete response rate 40.0%. Seventy percent of patients completed the study treatment. Progression-free survival and overall survival at 2 years were 40.0% and 80.0%, respectively. Adverse events of grade 3 or higher, including anemia, decreased lymphocyte count, neutropenia, and hypokalemia, were observed in eight patients. Alternating chemotherapy with Bd/Ld might be feasible, but its efficacy should be verified further.