Sevelamer reduces calcium load and maintains a low calcium-phosphorus ion product in dialysis patients

Background. Sevelamer HCl, a non-aluminum, non-calcium containing hydrogel, has proved an effective phosphate binder in North American hemodialysis pa tients. This single-center, open-label, dose titration study assessed the e fficacy of sevelamer in a cohort of European hemodialysis patients with dif ferent dietary habits, in particular with lower phosphate intake. The aim o f the study was to obtain a calcium x phosphate product lower than 60 mg(2) /dL(2) in all patients. Methods. Administration of calcium- or aluminum-based phosphate binders was discontinued during a two-week washout period. Nineteen patients whose ser um phosphate level at the end of washout was greater than 5.5 mg/dL (1.78 m mol/L) qualified to receive sevelamer for six weeks. Based on the degree of hyperphosphatemia during washout, patients were started on 403 mg sevelame r capsules with a dose schedule different front previous studies. Only one capsule was administered at breakfast, and the rest of the phosphate binder was divided equally at die two main meals. Sevelamer could be increased by two capsules per day every two weeks, if necessary. A second two-week wash out period followed. Results. Mean serum phosphorus rose from a baseline of 5.3 +/-1.0 to 7.4 +/ -1.4 mg/dL at the end of washout, then declined to 5.4 +/-0.8 mg/dL (p < 0. 001) by the end of the six-week treatment period and rebounded significantl y to 7.1 +/-1.1 mg/dL after the second two-week washout. Calcium x phosphat e product showed a similar pattern, decreasing significantly from 64.1 +/- 14.1 to 46.9 +/-7.4 mg(2)/dL(2) (p < 0.001) after six weeks of sevelamer. A level of less than 50 mg(2)/dL(2) was reached by 68% of patients, and 95% had less than 60 mg(2)/dL(2). The mean dose of sevelamer at the end of trea tment was 3.1 +/- 0.6 g per day. As expected, calcium declined from 9.2 +/- 0.5 to 8.7 mg/dL (p <0.01) during the initial washout after stopping calciu m-based phosphate binders, but remained stable thereafter. Ionized calcium did not change significantly throughout the washout and sevelamer treatment . However, interruption of calcium salts led to a 81% reduction of total ca lcium intake. Conclusions. We confirmed in an European sample of hemodialysis patients th at sevelamer can reduce phosphate levels without inducing hypercalcemia. Th e drug can also be successfully used to reduce mean calcium x phosphate lev els below 50 mg(2)/dL(2), closer to normal values. Although similar results can be obtained with other phosphate binders, a concomitant accumulation o f aluminum, calcium or magnesium could be detrimental to patients.