Real-World Dose-Relativity, Tablet Burden, and Cost Comparison of Conversion Between Sevelamer Hydrochloride/Carbonate and Lanthanum Carbonate Monotherapies

Abstract

PurposeSevelamer hydrochloride/carbonate (SH/C) and lanthanum carbonate (LC) are noncalcium-based phosphate binders used for the management of hyperphosphatemia in patients with end-stage renal disease (ESRD). The objectives of this study were to examine the dose-relativity, tablet burden, and cost difference of bidirectional conversion between SH/C and LC monotherapy in a large cohort of real-world patients with ESRD. MethodsThis retrospective cohort study included three 30-day preconversion periods (days −90 to −61, −60 to −31, and −30 to −1) followed by three 30-day postconversion periods (days 1 to 30, 31 to 60, and 61 to 90); day 0 was the index date of conversion. The full analysis population (FAP) comprised two cohorts: SH/C to LC (S–L) converters and LC to SH/C (L–S) converters. The SH/C:LC dose-relativity ratio was assessed in the dose-relativity subset, defined as patients whose serum phosphate levels fell within a caliper range of ±0.5 mg/dL in the final preconversion (days −30 to −1) and postconversion (days 61 to 90) periods. Tablet burden and phosphate binder costs were assessed in the FAP. Phosphate binder costs were based on average wholesale prices. FindingsThe FAP contained a total of 303 patients, comprising the S–L (128 patients) and L–S (175 patients) converter cohorts. The dose-relativity subset contained 159 patients, 72 from the S–L cohort and 87 from the L–S cohort. The overall mean SH/C:LC dose-relativity ratio was 2.27 (95% CI, 2.04 to 2.52). In SH/C dose strata >800 to 2400, >2400 to 4800, >4800 to 7200, and >7200 mg/d, overall mean dose-relativity ratios were 0.79 (95% CI, 0.57 to 1.10), 1.45 (95% CI, 1.20 to 1.75), 2.05 (95% CI, 1.75 to 2.39), and 3.24 (95% CI, 2.89 to 3.66), respectively. The overall mean tablet burden was 6.6 tablets per day lower with LC monotherapy than with SH/C monotherapy (95% CI, −7.1 to −6.0; P < 0.0001). The overall mean binder cost/patient per month was $1080.40 for SH/C compared with $1006.20 for LC, corresponding to a mean binder cost saving for LC of $74.20/patient per month (95% CI, −141.80 to −6.63; P = 0.032). SH/C >7800 mg/d was the inflection point at which conversion to LC resulted in mean cost savings. Patients requiring SH/C >7800 mg/d comprised 50% of the FAP. ImplicationsConverting patients with ESRD and hyperphosphatemia from SH/C to LC monotherapy offers potential drug cost savings and a significant reduction in the daily tablet burden, without compromising the effective management of serum phosphate levels.