Ardelyx tanks as FDA sees deficiencies in tenapanor NDA

Shares of California, USA-based cardiorenal specialist Ardelyx (Nasdaq: ARDX) plunged more than 70% to $2.28 in after-hours trading on Monday, as the company revealed the US regulator is not ready to approve its tenapanor for dialysis patients.

Ardelyx said yesterday it received a letter from the US Food and Drug Administration on July 13, 2021, stating that, as part of its ongoing review of the company's New Drug Application (NDA) for the control of serum phosphorus in adult patients with chronic kidney disease (CKD) on dialysis, the FDA has identified deficiencies that preclude discussion of labeling and post-marketing requirements/commitments at this time.

The letter stated that the notification does not reflect a final decision on the information under review. The company immediately requested a meeting to discuss the deficiencies and was notified by the FDA today that the request for a meeting was denied. While the FDA has not provided specific details regarding the deficiencies, the agency noted that a key issue is the size of the treatment effect and its clinical relevance.