Clinical effects of the new phosphorus binder, bixalomer in hemodialysis patients switched from sevelamer hydrochloride.

It has been reported that sevelamer hydrochloride, which is often used as a polymer phosphorus (P) binder for managing serum P concentration in dialysis patients, causes gastrointestinal adverse effects such as constipation, etc. The reason for this is thought to be that sevelamer hydrochloride has high water absorption, causing it to absorb water and swell in the gastrointestinal tract. In June 2012, the new polymer P binder bixalomer was launched in Japan. Since bixalomer has low swelling due to water absorption, it can be expected to alleviate adverse effects in the gastrointestinal system. In our study, for 21 cases of maintenance hemodialysis patients undergoing treatment with sevelamer hydrochloride at our hospital, the P binder was switched from sevelamer hydrochloride to the same dosage of bixalomer, and the concentrations of serum P, corrected calcium (Ca) and whole parathyroid hormone (PTH) before and one month after the switch were compared. In addition, gastrointestinal symptoms (acid reflux, abdominal pain, indigestion, diarrhea and constipation) were evaluated before and after the switch using a questionnaire based on the Japanese version of the Gastrointestinal Symptom Rating Scale (GSRS). By switching to bixalomer, serum P concentration was significantly reduced (P=0.024), but there were no significant changes observed for serum corrected Ca and whole PTH. Furthermore, there were no significant changes observed for all five of the evaluation items of the GSRS, before and after the switch. These results suggest that although bixalomer can more potently reduce the serum P concentration than sevelamer hydrochloride, there were no significant differences in the effects of both P binders on the gastrointestinal symptoms.