Shares of Ardelyx dropped in after-market trading earlier this week after the AstraZeneca partner acknowledged that its lead drug tenapanor was unimpressive in a Phase IIa study.
Ardelyx, based in California, says that tenapanor missed the primary endpoint among 154 patients with Stage 3 chronic kidney disease (CKD) and Type 2 diabetes, and was unable to markedly decrease the urinary albumin-creatinine ratio compared to a placebo, according to FierceBiotech.
Ardelyx signaled AstraZeneca that it has to make choices about the partnership by June 29. If AstraZeneca does stay with Ardelyx, then the company could be in line for up to $20 million in milestones, notes FierceBiotech.
While Ardelyx claimed a victory in a Phase IIb study of tenapanor for irritable bowel syndrome (IBS) a few weeks ago, investors were troubled by signs that the drug caused serious diarrhea in many patients and backed off, with shares plunging 30 percent.
Tenapanor is an NHE3 sodium transport inhibitor 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 stomach. In 2012 AstraZeneca signed a $272 million partnership deal on the drug as it worked 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,” says 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,” Raab adds. “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.”