Carfilzomib vs bortezomib in patients with multiple myeloma and renal failure: a subgroup analysis of ENDEAVOR

In ENDEAVOR, carfilzomib (56 mg/m²) and dexamethasone (Kd56) demonstrated longer progression-free survival (PFS) over bortezomib and dexamethasone (Vd) in patients with relapsed/refractory multiple myeloma (RRMM). Here we evaluated Kd56 vs Vd by baseline renal function in a post hoc exploratory subgroup analysis. The intent-to-treat population included 929 patients (creatinine clearance [CrCL] ≥15 to <50 mL/min, n = 85 and n = 99; CrCL 50 to <80 mL/min, n = 186 and n = 177; and CrCL ≥80 mL/min, n = 193 and n = 189 for Kd56 and Vd arms, respectively). In these respective subgroups, median PFS was 14.9 vs 6.5 months (hazard ratio [HR], 0.49; 95% confidence interval [CI], 0.320-0.757), 18.6 vs 9.4 months (HR, 0.48; 95% CI, 0.351-0.652), and not reached (NR) vs 12.2 months (HR, 0.60; 95% CI, 0.434-0.827) for those receiving Kd56 vs Vd, respectively; median overall survival (OS) was 42.1 vs 23.7 months (HR, 0.66; 95% CI, 0.443-0.989), 42.5 vs 32.8 months (HR, 0.83; 95% CI, 0.626-1.104), and NR vs 42.3 months (HR, 0.75; 95% CI, 0.554-1.009). Complete renal response (ie, CrCL improvement to ≥60 mL/min in any 2 consecutive visits if baseline CrCL <50 mL/min) rates were 15.3% (95% CI, 8.4-24.7) and 14.1% (95% CI, 8.0-22.6) for those receiving Kd56 vs Vd, respectively. In a combined Kd56 and Vd analysis, complete renal responders had longer median PFS (14.1 vs 9.4 months; HR, 0.805; 95% CI, 0.438-1.481) and OS (35.3 vs 29.7 months; HR, 0.91; 95% CI, 0.524-1.577) vs nonresponders. Grade ≥3 adverse event rates in the respective subgroups were 87.1% vs 79.4%, 84.4% vs 71.8%, and 77.1% vs 65.9% for those receiving Kd56 vs Vd, respectively. Thus, Kd56 demonstrated PFS and OS improvements over Vd in RRMM patients regardless of their baseline renal function. The ENDEAVOR trial was registered at www.clinicaltrials.gov as #NCT01568866.