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 hemodia lysis patients. Patients and methods: We performed a randomized clinical tr ial to compare the efficacy of RenaGel alone and RenaGel with calcium, usin g the serum phosphorus concentration and intact parathyroid hormone (PTH) a s the principal outcomes of interest. Calcium (900 mg elemental) was provid ed 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 st udy period (2 weeks washout, 12 weeks treatment, 2 weeks washout). 49% of s ubjects were taking vitamin D metabolites. Results: Serum phosphorus and PT H rose significantly when patients stopped their phosphate binders during b oth washout periods. RenaGel and RenaGel with calcium were equally effectiv e at reducing serum phosphorus (mean change -2.4 mg/dL vs. -2.3 mg/dL). Ren aGel with calcium was associated with a small increase in serum calcium (me an 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 metabo lites 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). Ad verse events were seen with equal frequency in both groups, being generally mild in intensity, and rarely attributable to the drugs. Conclusion: We co nclude that RenaGel and RenaGel with calcium are similarly effective in the treatment of ESRD-related hyperphosphatemia. Provision of supplemental cal cium or metabolites of vitamin D with RenaGel may enhance control of hyperp arathyroidism.