The FDA has denied Ardelyx’s new drug application (NDA) for tenapanor as a treatment for chronic kidney disease in adults on dialysis, citing concerns over the treatment’s effectiveness.

The agency had previously extended its Prescription Drug User Fee Act (PDUFA) decision date on the NDA from April to July 29, to gather more data.

Ardelyx said it conducted weeks of label discussions with the FDA in early April and that it submitted robust data from three trials with 1,000 participants that showed all three studies met their primary endpoints.

The California-based company said it requested a meeting to discuss the matter but was denied. However, it believes that the FDA’s notification “does not reflect a final decision” on the therapy.