Study design and treatment schema. *Assessment on days 1 and 15 of cycle 1 and day 1 of each subsequent cycle using modified IMWG Uniform Criteria with the addition of nCR. †Patients achieving a PR after cycle 4 underwent SCC and then continued CRd with the option to proceed to ASCT. ‡Initial dose of 20 mg/m² during cycle 1 days 1-2 for all patients regardless of dose cohort. §At the discretion of the investigator, patients could receive 4 mg of dexamethasone orally or intravenously on days 2, 9, and 16 (cycles 1 and 2) before the infusion of carfilzomib if signs of tumor flare-up were present. ¶Or the last tolerated dose. ASCT indicates autologous stem cell transplantation; CRd, carfilzomib, lenalidomide, dexamethasone; LEN, lenalidomide monotherapy; and PR, partial response.