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Abstract: PO1732

Long-Term Safety of Tenapanor for the Control of Serum Phosphorus in Patients with CKD on Dialysis: Serum Electrolytes and Albumin

Session Information

Category: Health Maintenance, Nutrition, and Metabolism

  • 1300 Health Maintenance, Nutrition, and Metabolism

Authors

  • Pergola, Pablo E., Renal Associates PA, San Antonio, Texas, United States
  • Fogli, Jeanene, Ardelyx Inc, Fremont, California, United States
  • Yang, Yang, Ardelyx Inc, Fremont, California, United States
  • Spiegel, David M., Ardelyx Inc, Fremont, California, United States
Background

Tenapanor, an investigational first-in-class phosphate absorption inhibitor (PAI), blocks the paracellular absorption of phosphate in the gastrointestinal tract by local inhibition of the sodium-hydrogen exchanger (NHE3). Tenapanor is being studied as a non-binder approach for the management of hyperphosphatemia in patients on dialysis and it is dosed as one pill (10, 20, or 30 mg) twice daily. Due to its novel mechanism of action, it is important to understand its safety profile, including any potential effects on serum electrolytes and albumin.

Methods

This report evaluates the effects of tenapanor on serum electrolyte and albumin concentrations using data from 3 pivotal trials in which tenapanor met its primary phosphorus-lowering endpoint. Trials included a 12-week monotherapy study (BLOCK), a 52-week monotherapy study (PHREEDOM), and a 4-week tenapanor + phosphate binder combination study (AMPLIFY). Serum electrolytes and albumin were measured per study protocol in central research laboratories.

Results

Tenapanor was generally well tolerated, with diarrhea being the only adverse event reported by >5% of patients. Diarrhea was typically mild to moderate in severity, was transient, and resolved with continued treatment. Data from all 3 trials showed that tenapanor treatment, either alone or in combination with phosphate binders, resulted in no clinically meaningful changes in measured serum electrolytes or albumin at any time point. Data from patients treated with tenapanor continuously for 52 weeks in the longest trial, PHREEDOM, are shown in the table.

Conclusion

In these clinical trials, tenapanor inhibited paracellular absorption of phosphate and decreased serum phosphorus with an acceptable safety profile, with no observed effect on serum electrolytes or albumin in patients on maintenance dialysis with hyperphosphatemia.

Laboratory parameterBaseline
(mean ± SD)
Week 26
(mean ± SD)
Week 52
(mean ± SD)
Bicarbonate (mmol/L)23.6 ± 3.124.4 ± 2.924.5 ± 3.2
Calcium (mg/dL)8.2 ± 0.88.4 ± 0.88.7 ± 0.7
Chloride (mmol/L)96.9 ± 4.097.2 ± 3.797.1 ± 3.8
Magnesium (mg/dL)2.5 ± 0.32.5 ± 0.32.5 ± 0.3
Potassium (mmol/L)4.8 ± 0.84.9 ± 0.74.8 ± 0.7
Sodium (mmol/L)136.4 ± 3.8136.1 ± 3.4136.3 ± 3.2
Albumin (g/dL)4.0 ± 0.34.0 ± 0.33.9 ± 0.3

Funding

  • Commercial Support