Ardelyx IBS drug edges closer to the market
- Tenapanor, which has been in development with Fremont, CA-based Ardelyx for quite a number of years, may finally be heading towards the market after a Phase 3 trial in irritable bowel syndrome with constipation (IBS-C) hit statistical significance for its primary and all its secondary endpoints.
- In the pivotal T3MPO-2 study, more treated patients than placebo patients had a 30% improvement in abdominal pain and an increase of one or more spontaneous bowel movements in the same week for at least six of the 12 weeks of treatment (36.5% vs 23.7%). Tenapanor was well-tolerated, but 16% of treated patients reported diarrhea, compared with 3.7% of patients on placebo.
- The company plans to submit a New Drug Application in the second half of 2018, including data from the T3MPO-3 one-year open-label study. Ardelyx shares climbed over 36% after hours on Wednesday.
Treating constipation isn't the most glamorous of indications, but for the 11+ million people in the U.S. who have irritable bowel syndrome with constipation (IBS-C), any move that would help this embarrassing and lifestyle-limiting disorder would be more than welcome.
"These results are a game-changer for patients with IBS-C, their treating physicians and for Ardelyx as a company," said Mike Raab, president and CEO of Ardelyx. "They demonstrate the significant benefit tenapanor can have for patients with IBS-C, importantly, leading to a normalization of bowel movements for many patients."
The next step will be to find a new partner for the project and try to push through to the market, completing what has been a long journey so far. And at the moment, Ardelyx needs all the good news it can get.
Since February 2015 shares of Ardelyx have been down about 80%. The drop was due to partner AstraZeneca reporting higher than expected levels of diarrhea in patients treated with tenapanor in a Phase 2 study of the drug in dialysis patients with hyperphosphatemia in chronic kidney disease. This slump wasn't helped by AstraZeneca terminating its partnership in June 2015, and Sanofi pulling out of an option and license agreement in September 2015.
Tenapanor, which remains in the gut, reduces the absorption of dietary sodium and so relieves constipation by increasing the fluid in the gut. It also relieves abdominal pain in IBS-C, but the mechanism isn't quite clear.
In renal disease, the sodium uptake blocking reduces the amount of phosphate that can be absorbed, so reducing hyperphosphatemia. Tenapanor is also in Phase 3 for hypophosphatemia in end-stage renal disease, a different population to the earlier kidney disease study, and in February this year, Ardelyx reported positive data from the study. However, diarrhea was still an issue and critics have suggested that there was cherry-picking of data.
- Ardelyx Statement
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