OBJECTIVES: The phosphate binders sevelamer hydrochloride (SH) and lanthanum carbonate (LC) will be included in the Medicare bundled reimbursement scheme from 2016. The aim of this study was to evaluate the cost implications of switching patients from SH to LC monotherapy. METHODS: A post hocanalysis of the cost implications of switching from SH to LC monotherapy was performed using data from a 16 week, phase 4, real-world clinical study (n = 953). Daily LC doses were titrated to maintain the level of phosphate control achieved with SH at baseline. Costs of mean daily drug doses were calculated using the average wholesale price (LC 1000 mg: $8.82; SH 800 mg: $3.71). Analyses were performed by baseline SH dose group (per mean daily dose) and by real clinical doses of SH and LC. RESULTS: Mean (SD) serum phosphate levels were 5.88 (1.69) mg/dL at baseline and 5.93 (1.85) mg/dL after 16 weeks of LC treatment. Mean doses and associated costs by baseline SH dose group were as follows: SH 2400–4800 mg/day: 4051 mg/day ($18.79/day) versus LC 2445.4 mg/day ($21.57/day); SH >4800–7200 mg/day: 7047 mg/day ($32.68/day) versus LC 2823 mg/day ($24.90/day); SH >7200–9600 mg/day: 9253 mg/day ($42.91/day) versus LC 3018 mg/day ($26.62/day); SH >9600 mg/day: 13 150 mg/day ($60.98/day) versus LC 3156 mg/day ($27.84/day). Analysis by real clinical doses revealed that LC 3000 mg/day ($26.46/day) is less costly than SH 6400 mg/day ($29.68/day) and 7200 mg/day ($33.39/day), but not SH 5600 mg/day ($25.97/day). At baseline, 65% of patients were receiving SH ≥6400 mg/day. CONCLUSIONS: Our analysis showed that LC is more cost-effective than SH in patients taking SH ≥6400 mg/day (65% of patients at baseline). Switching these patients to LC 3000 mg/day would offer cost savings, a reduced daily pill burden (3 vs >8/day) and effective maintenance of phosphate control.