We report the final results from a multicenter, open-label phase I study of carfilzomib plus lenalidomide and dexamethasone in Japanese patients with heavily pretreated relapsed and/or refractory multiple myeloma (RRMM). Twenty-six RRMM patients were enrolled and received a median of 4.0 prior regimens; 12/26 patients (46.2%) completed the planned 18 administration cycles (mean number of cycles: 14.5 ± 4.9). The safety profile was consistent with that of previous carfilzomib studies. All patients experienced adverse events (AEs), but no new safety concerns were observed. The most common grade ≥ 3 AEs (incidence: ≥ 10%) were lymphocyte count decreased (46.2%), platelet count decreased (42.3%), and neutrophil count decreased (34.6%). The overall response rate was 88.5% (23/26; 90% confidence interval: 72.8-96.8). Complete response (CR) or better was achieved by 30.8% of patients compared with 3.8% in the interim analysis. The median time to CR or better response was 9.4 months. Median progression-free survival and duration of response were 19.5 months and 20.3 months, respectively. Median overall survival was not reached. Long-term administration of carfilzomib produced deep response and long-term disease control. The combination of carfilzomib plus lenalidomide and dexamethasone was well tolerated and showed promising clinical efficacy for heavily pretreated RRMM patients. CLINICAL TRIAL REGISTRATION: This clinical trial was registered in the database clinicaltrials.jp (clinical trial registration number: Japic CTI 142677).
Keywords: Carfilzomib; Clinical trial; Dexamethasone; Lenalidomide; Multiple myeloma.