FDA grants appeal for Ardelyx chronic kidney disease drug after July 2021 rejection
The FDA bestowed good tidings upon Ardelyx’s experimental chronic kidney disease drug Thursday morning.
Regulators told the biotech they would hear an appeal to its complete response letter, potentially setting Ardelyx up for an approval resubmission in the first half of next year. The move follows a post-CRL advisory committee meeting last month in which the FDA’s Cardiovascular and Renal Drugs panelists voted in favor of both monotherapy and combination regimen approvals.
“To say I’m excited would be an understatement,” president and CEO Mike Raab said on an analyst call Thursday morning. Investors didn’t feel the same, however, as Ardelyx shares $ARDX fell about 8%.
Ardelyx also won’t have to submit new data, Raab said. Some of the analyses submitted for the advisory committee “may very well be part of what they would want us to submit,” he said. “But that’s data that they already have as part of the” drug application.
The news provides new momentum for Ardelyx’s roller-coaster attempt to get its drug, known as tenapanor, across the finish line. FDA originally rejected the drug back in July 2021 despite three positive Phase III readouts. Analysts at the time declared an approval “all but certain.”
Ardelyx originally had focused on treating chronic kidney disease writ large, but narrowed that aim to a subset of patients with an overabundance of phosphate in the blood after earlier, broader studies flopped. That condition, called hyperphosphatemia, occurs in about 80% of patients with end-stage kidney disease on maintenance dialysis.
The FDA wasn’t convinced, and Ardelyx’s stock lost more than 70% of its value, and the company made rounds of job cuts. As the appeal and advisory committee processes played out, regulators eventually said “the magnitude of the treatment effect is unclear.”
When tenapanor was first rejected, the implication of the FDA’s response was that the agency wanted Ardelyx to conduct a new study looking at clinical outcomes, Raab told Endpoints News Thursday. That wasn’t something the biotech was willing to do, he said: “Given the complexity of the disease, the moribund nature and the speed at which they die of many things, makes an outcome study nearly impossible.”
Now, the company will focus on discussions with the FDA, which will likely start with a Type A meeting, Raab added. Ardelyx is being included in discussions for the drug’s potential label, and is expected to be branded as Xphozah.
If the FDA ultimately reverses course and approves tenapanor here, it will be the drug’s second green light after a 2019 thumbs-up for irritable bowel syndrome with constipation in adults.