Ardelyx, Inc. (Nasdaq: ARDX), a biopharmaceutical company focused on the discovery, development, and commercialization of innovative first-in-class medicines to improve treatment for people with kidney and cardiorenal diseases.
Recently they announced that the Prescription Drug User Fee Act (PDUFA) date for tenapanor for the control of serum phosphorus in adult patients with chronic kidney disease (CKD) on dialysis has been extended by three months.
Following constructive labeling discussions with the U.S. Food and Drug Administration (FDA) that began in early April, the agency made a recent information request that required the company to submit additional analyses to help the agency better understand the clinical data in light of tenapanor’s novel mechanism of action as compared to approved therapies. In response, the company submitted the requested analyses which constitute a major amendment to the New Drug Application (NDA), resulting in an extension of the PDUFA date by three months to July 29, 2021.
“While disappointed in the delay, we understand the impact that the COVID-19 pandemic has had on the operations of the agency,” said Mike Raab, president and chief executive officer of Ardelyx. “We appreciate the constructive labeling discussions with the agency over the past month and believe that the additional analyses submitted in response to recent dialogue with the agency reinforce the extensive clinical evidence we generated on tenapanor. We look forward to continuing to work closely and constructively with FDA during the remainder of the review process. We are confident in the comprehensive data set, are well prepared for the launch of tenapanor upon potential approval and are dedicated to bringing this important medicine to patients.”
The NDA for tenapanor for the control of serum phosphorus is supported by a comprehensive development program involving more than 1,000 patients, including three Phase 3 clinical trials, all of which met their primary and key secondary endpoints.
About Tenapanor for Hyperphosphatemia
Tenapanor, discovered and developed by Ardelyx, is a first-in-class, proprietary, oral medicine for which an NDA is under review by the FDA for the control of serum phosphorus in adult patients with CKD on dialysis. Hyperphosphatemia is a serious condition that is an independent predictor of morbidity and mortality in dialysis patients. Despite treatment with currently available drugs, 40% of patients continue to have phosphorous levels outside of target ranges in any given month. Recent data has shown that 77% of patients are unable to consistently maintain target phosphorus levels over a six-month period. Tenapanor has a unique mechanism of action and acts locally in the gut to inhibit the sodium hydrogen exchanger 3 (NHE3).
This results in a proposed conformational change of the epithelial cell tight junctions, thereby significantly reducing paracellular permeability to phosphate and decreasing phosphate absorption through this primary pathway. Ardelyx is conducting NORMALIZE, an ongoing extension study of the PHREEDOM Phase 3 monotherapy study, which is designed to evaluate the ability of tenapanor, as monotherapy or in combination with sevelamer, to achieve serum phosphorus levels in the normal range (2.5 – 4.5 mg/dL) in patients with chronic kidney disease (CKD) on dialysis.
Planned analyses have demonstrated that the use of tenapanor as a foundational approach, as monotherapy or in combination with sevelamer carbonate, produces a significant phosphorus-lowering effect. Preliminary data from the NORMALIZE trial demonstrates that after ~20 months of treatment with tenapanor alone or with low doses of sevelamer, patients exhibited a mean serum phosphorus reduction of 2.33 mg/dL, from a mean baseline phosphorus of 7.27 mg/dL at the beginning of the PHREEDOM trial to a mean of 4.94 mg/dL.