Weekly carfilzomib, lenalidomide, and dexamethasone in relapsed or refractory multiple myeloma: A phase 1b study

Twice‐weekly carfilzomib (27 mg/m2) with lenalidomide‐dexamethasone (KRd) is a standard‐of‐care in relapsed or refractory multiple myeloma (RRMM). This phase 1b study evaluated KRd with once‐weekly carfilzomib in RRMM. Patients received carfilzomib (30‐minute infusion; 56 or 70mg/m2) on days 1, 8, and 15; lenalidomide 25 mg on days 1‐21; and dexamethasone 40 mg on days 1, 8, 15, and 22 (day 22 omitted for cycles 9+) of 28‐day cycles. Primary objective was safety/tolerability; efficacy was a secondary objective. Fifty‐six RRMM patients enrolled: 22 during dose evaluation (56‐mg/m2, n = 10; 70‐mg/m2, n = 12) and 34 during dose expansion (all initiated dosing at 70 mg/m2). After 2 fatal adverse events (AEs) during 70‐mg/m2 dose expansion, dosage reduction to 56 mg/m2 was permitted. Results are presented for carfilzomib 56‐mg/m2 (n = 10) and 70‐mg/m2 groups (dose evaluation/expansion; n = 46). Median carfilzomib dose was 53.2 mg/m2 (56‐mg/m2 group) and 62.4 mg/m2 (70‐mg/m2 group). Grade ≥3 AE rates were 70.0% (56 mg/m2) and 69.6% (70 mg/m2). Overall response rates were 90.0% (56 mg/m2) and 89.1% (70 mg/m2); ≥very good partial response rates were 50.0% (56 mg/m2) and 73.9% (70 mg/m2). Once‐weekly KRd was active with acceptable toxicity in RRMM, supporting further evaluation of this regimen.