Shares of Ardelyx plunged in after-market trading Tuesday after the AstraZeneca partner conceded failure in a Phase IIa study of its troubled lead drug.
The Fremont, CA-based biotech says that tenapanor flunked the primary endpoint among 154 patients with Stage 3 chronic kidney disease (CKD) and Type 2 diabetes, failing to significantly decrease the urinary albumin-creatinine ratio compared to placebo.
The ratio dropped 16% in the drug arm and 11% in the placebo group. The stock dropped 26% on the news.
Ardelyx ($ARDX) immediately signaled that AstraZeneca ($AZN) has some big decisions to make about the partnership by June 29 and seemed ready to go it alone if necessary. If AstraZeneca does go ahead, then the biotech could be in line for up to $20 million in milestones. But the odds are stacking up against the company.
Just weeks ago Ardelyx claimed a win in a Phase IIb study of tenapanor for irritable bowel syndrome (IBS), but investors were rattled by signs that the drug triggered serious diarrhea in many patients and triggered a rout, with shares plunging 30%.
Tenapanor is an NHE3 sodium transport inhibitor which is designed to force the body to flush sodium through feces rather than urine, sparing kidneys and helping patients with IBS, end-stage renal disease and CKD. NHE3 is a protein needed to absorb sodium in the gut. AstraZeneca signed a $272 million partnership deal on the drug back in 2012 as it launched a frenzy of dealmaking aimed at repairing a damaged pipeline.
"We continue to work with AstraZeneca as they evaluate the data, and we are preparing for the continuation of the development of tenapanor under a variety of different scenarios," said Mike Raab, president and CEO of Ardelyx. "We are preparing for an end of Phase II meeting for IBS-C with the FDA scheduled to occur in June. Should AstraZeneca decide to return the program to us, we seek to be in a position to initiate a Phase III clinical program for tenapanor in IBS-C in the fourth quarter of 2015. Additionally, we intend to be prepared to continue the development of tenapanor for the treatment of hyperphosphatemia in CKD patients on dialysis. We believe that tenapanor can be a best-in-class treatment for IBS-C and hyperphosphatemia and we hope to accelerate the development for these underserved conditions either independently or with AstraZeneca."
- here's the release