- Adding tenapanor to phosphate binders significantly reduced serum phosphorus in a phase 3 trial of dialysis-dependent patients with refractory hyperphosphataemia, according to a company news release.
Why this matters
- Minimally absorbed tenapanor reduces phosphorus uptake by inhibiting intestinal sodium/hydrogen exchanger 3 (NHE3).
- AMPLIFY double-blind, randomised trial of 236 dialysis-dependent patients with hyperphosphataemia (5.5-10 [mean, 6.8] mg/dL) despite a stable phosphate binder regimen.
- Participants received add-on placebo or tenapanor (30 mg twice daily, titrated based on need and tolerance).
- Funding: Ardelyx.
- Primary endpoint: mean reduction in serum phosphorus at 4 weeks was significantly greater with tenapanor vs placebo (−0.84 vs −0.19 mg/dL; P=.0004).
- Weekly decreases ranged from −0.84 to −1.21 mg/dL (P≤.0004).
- Secondary endpoints:
- 49.1% of tenapanor-treated patients achieved serum phosphorus
- FGF23 levels, associated with cardiovascular risk, were reduced by 22%-24% with tenapanor vs placebo (P≤.0027).
- Discontinuation rates were 4.3% with tenapanor vs 2.5% with placebo.
- Discontinuation for loose stools/diarrhea: 2.6% vs 0.8%.
- Loose stools/diarrhoea were the most common adverse event (placebo-adjusted rate, 36%).
- Cases occurred primarily in the first 5 days and were transient in nature.
- The source of these data is a news release issued by Ardelyx, Inc. of Fremont, California. Results of the AMPLIFY study have not been published in a peer-reviewed journal.