Despite the fact that the FDA has rejected the marketing application for Xphozah, a therapy developed by Ardelyx for the treatment of chronic kidney disease (CKD), the company’s advisors have a more positive outlook on the medication.
Yesterday, the Cardiovascular and Renal Drugs Advisory Committee (CRDAC) came to the conclusion that the benefits of Xphozah (tenapanor) outweigh its risks when used as a monotherapy to treat high phosphate levels in the blood in adults with CDK who are receiving dialysis treatment. The vote was nine to four in favor of this conclusion.
The panel also decided that it is safe to use in combination with traditional phosphate binder medications, which is the only therapy that has been approved for hyperphosphatemia, by a vote of 10 to 2, with one member abstaining from the voting. Xphoza blocks the body’s ability to absorb phosphate in a different manner than other medications.
Patients who are receiving dialysis are at an increased risk for developing hyperphosphatemia, which is medically referred to as having high phosphate levels in the blood. In severe circumstances, it is capable of causing difficulties with the bones and muscles, in addition to increasing the risk of heart attacks and strokes.
The FDA’s advisors have given the NHE3 inhibitor a good review, which is somewhat at odds with the agency’s own perspective on the substance. According to the briefing documents that were issued in advance of the conference, it appears that it still has reservations about the effectiveness of Xphozah, notably about the fact that the size of its effect is less than that of binder medications such as sevelamer.
Ardelyx submitted an appeal to the Food and Drug Administration (FDA) in response to the FDA’s issuance of a complete response letter (CRL) for Xphozah last year. In the letter, the FDA requested that the company conduct another clinical trial to demonstrate a greater effect on hyperphosphataemia, which is a clinical endpoint associated with excess phosphate in dialysis patients. This appeal led to the convening of the advisory committee.
Ardelyx stated that it is now anticipated that the Office of New Drugs will offer a response to its appeal within the next thirty days.
As an alternative to existing drugs that offer a lower daily pill burden, as well as a combination therapy for patients who are struggling to reduce phosphate despite treatment, analysts have previously projected that Xphozah will reach annual peak sales of several hundred million dollars. Xphozah is intended to be used in both of these capacities.
Irritable bowel syndrome with constipation is an indication that was authorized by the FDA in 2019 and is presently bringing in quarterly revenues of approximately $5 million. Tenapanor is already offered by Ardelyx for this condition under the brand name Ibsrela and is marketed by Ardelyx.
After-hours trading for Ardelyx’s stock, which had been halted the previous day in anticipation of the advisory committee’s deliberations, resulted in a 67% increase in the price of those shares when the news of the favorable CRDAC votes was announced.
“[The] vote by the CRDAC is a promising development for the chronic kidney disease community,” said Mike Raab, President and Chief Executive Officer of Ardelyx. “Patients continue to struggle to control serum phosphorus levels despite the use of currently available therapies, which are all limited to the phosphate binder class,” said Raab. “[The] vote by the CRDAC is a promising development for the chronic kidney disease community.”
“We are optimistic that the evidence from three phase 3 clinical trials involving more than 1,200 patients support the licensing of Xphozah in the US,” he continued. “Xphozah is a treatment for patients who have a condition known as phosphagen hypersensitivity syndrome.”