A randomized trial of sevelamer hydrochloride (RenaGel) with and without supplemental calcium. Strategies for the control of hyperphosphatemia and hyperparathyroidism in hemodialysis patients.

OBJECTIVE: We have previously shown sevelamer hydrochloride (RenaGel) to be an effective and well-tolerated treatment for hyperphosphatemia in hemodialysis patients.

PATIENTS AND METHODS: We performed a randomized clinical trial to compare the efficacy of RenaGel alone and RenaGel with calcium, using the serum phosphorus concentration and intact parathyroid hormone (PTH) as the principal outcomes of interest. Calcium (900 mg elemental) was provided as a once-nightly dose on an empty stomach. 71 patients were randomized and included in the intent-to-treat population; 55 completed the 16-week study period (2 weeks washout, 12 weeks treatment, 2 weeks washout). 49% of subjects were taking vitamin D metabolites.

RESULTS: Serum phosphorus and PTH rose significantly when patients stopped their phosphate binders during both washout periods. RenaGel and RenaGel with calcium were equally effective at reducing serum phosphorus (mean change -2.4 mg/dL vs. -2.3 mg/dL). RenaGel with calcium was associated with a small increase in serum calcium (mean change 0.3 mg/dL vs. 0.0 mg/dL in RenaGel group, P = 0.09) that was not statistically significant. During the treatment phase, the reduction in PTH tended to be greater in the RenaGel with calcium group (median change -67.0 vs. -22.5 pg/mL in RenaGel group, P = 0.07). Non-users of vitamin D metabolites treated with RenaGel with calcium experienced a significant decrease in PTH (median change -114.5 vs. -22 pg/mL in RenaGel group, P = 0.006). Adverse events were seen with equal frequency in both groups, being generally mild in intensity, and rarely attributable to the drugs.

CONCLUSION: We conclude that RenaGel and RenaGel with calcium are similarly effective in the treatment of ESRD-related hyperphosphatemia. Provision of supplemental calcium or metabolites of vitamin D with RenaGel may enhance control of hyperparathyroidism.