Ardelyx bags its first FDA OK for IBS, setting up a showdown with Allergan, Ironwood
In the first of what it hopes will be a couple of major regulatory milestones for its new drug, Ardelyx has bagged an FDA approval to market Ibsrela (tenapanor) for irritable bowel syndrome.
The drug’s first application will be for IBS with constipation (IBS-C), inhibiting sodium-hydrogen exchanger NHE3 in the GI tract in such a way as to increase bowel movements and decrease abdominal pain. This comes on the heels of two successful Phase III trials.
But Ardelyx, which specializes in cardiorenal diseases, has broader plans for their new trademark drug. Last week, they unveiled across-the-board positive results from their AMPLIFY study, testing the inhibitor on patients with chronic kidney disease (CKD) with high phosphate levels. And they’ve indicated optimism for the results of a second PHREEDOM study on patients with end-stage renal disease.
“With these milestones accomplished, and the PHREEDOM trial reading out in Q4, I have great confidence that we are well-positioned to file our NDA for hyperphosphatemia next year with potential approval and launch in 2021,” Ardelyx CEO Mike Raab said in a statement.
In the Phase III trials that fueled the FDA approval, Ardelyx primarily examined the portion of patients with who responded by the FDA definition: saw at least a 30% reduction in weekly average abdominal pain score and, during the same week, an increase of at least 1 complete spontaneous bowel movement, and did those for at least 6 of the 12 weeks. In the first study, the overall response rate was 37% compared to 24% in the placebo group. In the second study, it was 27% vs 19%.
Diarrhea was the most significant health risk, affecting 16% and 15% of patients in each study, against 4% and 2% in the placebo group.
An analysis from SVB Leerink noted that the placebo-adjusted response rate in these trials was lower than in trials for a key competitor: Linzess, sold by Allergan and Ironwood. But rates of diarrhea were lower and that if you raise the bar and look at if patients responded for 9 (rather than 6) of 12 weeks, Ibsrela outperforms.
“Overall, we believe these differences are minor in the grand scheme of things and puts Ibsrela at a competitive position vs on market IBS-C treatments,” they wrote.
Other, more outside-the-box treatments are in early stages at other companies. That includes Israeli biotech BiomX’s effort to concoct phage cocktails to remove IBS-causing bacteria from the gut, Whole Biome’s probiotic-style approach, and cannabinoid therapies from CB2 Therapeutics.
Ardelyx is still looking for a US partner to license the drug.