Effect of MCI-196 (colestilan) as a phosphate binder on hyperphosphataemia in aemodialysis patients: a double-blind, placebo-controlled, short-term trial

Background: MCI-196 (colestilan), an anion exchange resin, is widely used as an anti-hypercholesterolaemic drug in Japan. To evaluate the efficacy and safety of MCI-196 as a phosphate binder, a double-blind, randomized, placebo-controlled prospective trial was conducted in Japanese end-stage renal disease patients with hyperphosphataemia on intermittent haemodialysis treatment.

Methods: Phosphate binders were discontinued during a 2-week washout period. Subsequently, patients whose serum phosphorus levels were > or =6.5 mg/dl, but <10 mg/dl were eligible to enter the treatment protocol. Patients were randomized to either MCI-196 6 g/day or placebo for 2 weeks. The efficacy and safety of MCI-196 were assessed in 33 and 46 patients, respectively.

Results: Serum phosphorus in the placebo group increased by 0.84+/-0.95 mg/dl (mean+/-SD), while serum phosphorus in the MCI-196 group decreased by 0.55+/-1.23 mg/dl. The difference between the two groups was statistically significant (P = 0.002). A reduction of > or =1 mg/dl in serum phosphorus was observed in 43% in the MCI-196 group and 0% of patients in the placebo group (P = 0.0122). Calcium-phosphorus (CA x P) product, intact parathyroid hormone (iPTH) and low-density lipoprotein (LDL)-cholesterol in the MCI-196 group also decreased significantly compared with the placebo group, while serum calcium was unchanged. Adverse reactions were observed in 51.7% of the MCI-196 group and 29.4% of the placebo group (P = 0.2186). The most frequent adverse reactions in the MCI-196 group were gastrointestinal symptoms and signs, including constipation.

Conclusions: The present findings suggest that the short-term administration of MCI-196 is effective in decreasing serum phosphorus in haemodialysis patients. Its long-term efficacy needs to be evaluated.