Long-term treatment of hyperphosphatemia with bixalomer in Japanese hemodialysis patients.

Bixalomer is a nonabsorbable polymer that binds phosphate in the gastrointestinal tract and lowers the serum phosphate level by inhibiting phosphate absorption. The safety and efficacy of long-term bixalomer treatment were assessed in Japanese hemodialysis patients with hyperphosphatemia. This was a multicenter open-label study with a 48-week treatment period. The main efficacy endpoints were the serum phosphate level and rate of achieving the target serum phosphate range (3.5-6.0 mg/dL). Bixalomer was initiated at a dose of 1.5 g/day, which was increased to a maximum of 7.5 g/day depending on the serum phosphate response. Of 248 subjects who started treatment, 179 completed the study. The mean serum phosphate level decreased over time and remained around 5.5 mg/dL from weeks 16 to 48. The target serum phosphate level was reached in >50% of subjects by week 7 and was maintained in 65.2% to 75.9% until week 48. The incidence of adverse events and adverse drug reactions was 94.4% and 29.4%, respectively. There was a potential relationship with the study drug for four serious adverse events (ischemic colitis, hemorrhagic intestinal diverticulum, esophageal ulcer, and acute cholecystitis), which occurred in one patient each. Constipation was the most common adverse drug reaction (21.0%). Most adverse events and adverse drug reactions occurred soon after starting administration, and their incidence did not increase during long-term treatment. Bixalomer did not reduce the bicarbonate level or promote metabolic acidosis. Bixalomer is clinically useful for the long-term treatment of hyperphosphatemia.