Treatment of hyperphosphatemia with bixalomer in Japanese patients on long-term hemodialysis with gastrointestinal symptoms.

Bixalomer (Bix) is an amine-functional polymer, non-calcium-containing phosphate (P) binder, and has been clinically available in Japan recently. Bix is expected to cause fewer gastrointestinal (GI) side-effects as compared with sevelamer hydrochloride (SH), because of less expansion of Bix in the GI tract. In this prospective observational study, we evaluated changes in GI symptoms by the Gastrointestinal Symptom Rating Scale (GSRS) score in long-term hemodialysis (HD) outpatients with SH-associated GI symptoms who switched to Bix from SH. A total of 114 patients (age 63.7±10.8 year (mean±SD), female 65.5%, HD vintage 11.2±8.6 years, diabetes mellitus 27.4%) were enrolled. The GSRS score was checked at 0 and 12 weeks after the start of Bix. Bix was started at the initial dose of 750 mg/day, and then was titrated. Serum albumin, P and corrected calcium levels did not significantly change during Bix treatment. However, serum low-density lipoprotein-cholesterol and bicarbonate levels significantly increased during Bix treatment (P<0.001). In GSRS scores, total and domain-specific scores, including constipation, diarrhea, reflux and abdominal pain were significantly reduced at 0, 4, 12 and 24 weeks as compared with those at 0 weeks (P<0.05). This study shows that Bix was well tolerated and managed hyperphosphatemia effectively after switching from SH in Japanese patients on long-term HD. In addition, Bix might be less often associated with GI symptoms as compared with SH.