Purpose: The pharmacokinetics (PK) of carfilzomib have been previously studied in multiple myeloma patients with varying degrees of renal impairment (normal, mild, moderate, severe, and end-stage renal disease [ESRD]) at doses of 15 and 20 mg/m2. This study evaluated carfilzomib PK at higher doses of 27 and 56 mg/m2 in normal renal function and ESRD patients.
Methods: Patients received carfilzomib on two consecutive days/week for 3 weeks every 28-day cycle: 20 mg/m2 (cycle 1 day 1-2), escalated to 27 mg/m2 on cycle 1 day 8; if tolerated, 56 mg/m2 starting cycle 2 day 1. The primary objective was PK assessment with safety/tolerability and response rate as secondary and exploratory objectives, respectively.
Results: 26 patients were enrolled (15 normal, 11 ESRD). There was a trend toward higher area under the concentration time curve (AUC) and maximum concentration in ESRD versus normal renal function patients; however, high interpatient PK variability was discerned. Relative to patients with normal renal function, ESRD patients showed 33% higher AUC. Overall response rate was 43% for the normal renal function and 60% for the ESRD groups. Safety findings were generally similar between the two groups and consistent with the known safety profile of carfilzomib in multiple myeloma patients.
Conclusion: There were no meaningful differences in PK between patients with normal renal function and ESRD in light of carfilzomib exposure-response relationships. These results continue to support dosing recommendation that no starting dose adjustment of carfilzomib appears warranted in patients with baseline renal impairment.
Keywords: Carfilzomib; End stage renal disease; Multiple myeloma; Pharmacokinetics; Renal impairment.