Effect of tenapanor on bowel movements in hemodialysis patients with hyperphosphatemia based on a pooled post hoc analysis of three clinical trials

Hyperphosphatemia is a common complication in patients receiving dialysis. It is often managed with phosphate binders (PBs), which contribute to constipation and diarrhea. Tenapanor, a selective sodium/hydrogen exchanger 3 inhibitor, reduces intestinal phosphate absorption and can affect bowel movements. This pooled post hoc analysis of three Japanese phase 3 trials examined tenapanor’s effects on bowel movements and laxative prescribing by patient background. Outcomes included diarrhea incidence, changes in Bristol Stool Form Scale (BSFS) score, daily stool frequency, and laxative prescribing. These were evaluated across patient background and baseline PB type. Overall, 166 placebo- and 379 tenapanor-treated patients were included. Younger age, higher body mass index, presence of diabetic nephropathy, baseline laxative use, absence of probiotic use, and lower baseline bowel movement frequency were associated with lower diarrhea incidence by tenapanor within 8 weeks. In the tenapanor group, mean BSFS score and daily stool frequency increased from baseline to Week 1 across all background subgroups. The proportion of patients prescribed laxatives and the number of tablets prescribed tended to decrease over time compared with baseline in the tenapanor group. Tenapanor affected bowel movements and reduced laxative use across diverse patient backgrounds, supporting its use in patients with hyperphosphatemia receiving dialysis.