The US Food and Drug Administration’s (FDA) Cardiovascular and Renal Drugs Advisory Committee (CRDAC) has recommended Ardelyx’s Xphozah (tenapanor) for the control of serum phosphorus in adult patients with chronic kidney disease (CKD) on dialysis.
The committee voted nine to four in favour of Xphozah – a phosphate absorption inhibitor – to be administered as a monotherapy for treating this patient population, and voted ten to two, with one abstention, for the drug’s use alongside existing phosphate binder treatment.
The submission was supported by findings from a comprehensive development programme including more than 1,200 patients in three phase 3 clinical trials – PHREEDOM, BLOCK and AMPLIFY – evaluating the safety and efficacy of Xphozah, all of which met their primary and key secondary endpoints.
In PHREEDOM, as compared to patients treated with placebo, patients treated with Xphozah showed a statistically significant difference in least square mean serum phosphorus change from the end of the trial’s 26-week treatment period to the endpoint visit in the 12-week randomised withdrawal period.
Meanwhile, BLOCK demonstrated a statistically significant difference in serum phosphorus levels from the end of the trial’s eight-week treatment period to the end of the four-week randomised withdrawal period between the Xphozah-treated group and the placebo-treated group.
Finally, Xphozah-treated patients in AMPLIFY experienced a statistically significant mean reduction in serum phosphorus from baseline to the end of the four-week treatment period as compared to those treated in the binder arm (placebo in combination with phosphate binders).
Elevated levels of serum phosphorus in the blood, or hyperphosphatemia (HP), is a serious condition resulting in an abnormally elevated level of phosphorus in the blood, estimated to affect more than 745,000 dialysis patients in major developed countries.
As the kidney is the organ responsible for regulating phosphorus levels, when its function is significantly impaired, phosphorus is not adequately eliminated from the body. As a result, HP is a nearly universal condition among people with CKD on dialysis. Currently, phosphate binders are the only approved therapy for the condition.
“[The] vote by the CRDAC is a promising development for the CKD community, as patients continue to struggle to control serum phosphorus levels despite use of currently available therapies, which are all limited to the phosphate binder class,” said Mike Raab, president and chief executive officer of Ardelyx.