FDA Approves Irritable Bowel Syndrome Drug Ibsrela for Adults

According to a press release from the California-based biotechnology company Ardelyx, the US Food and Drug Administration (FDA) recently approved the company’s irritable bowel syndrome drug candidate Ibsrela (generic name tenapanor) for market use in the United States.

About Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is pretty self-explanatory as far as names go. It’s characterized by discomfort of varying levels originating in the large intestine and possibly radiating to surrounding tissues. Other symptoms include excess gas, constipation, or consistently loose stool.

The causes of IBS aren’t clearly defined. However, several factors are presumed to play a role – including nervous system abnormalities (abnormally sensitive nerves near the large intestine possibly being over-stimulated as it expands or contracts), inflammation of the intestines (some IBS patients have elevated levels of immune cells in their intestines), changes in microflora (the “good” bacteria that live in intestines and aid digestion), and abnormal muscle contractions.

Certain factors can aggravate existing symptoms of IBS, like stress or “trigger” foods (though food allergies are rarely the cause of IBS). Hormones are also thought to play a role. Women are twice as likely as men to develop the condition; increased discomfort around menstrual periods is also frequently reported.

About Ardelyx and the FDA Approval

Ibsrela, orally administered as a 50mg twice-a-day pill, is intended to combat constipation and decrease abdominal pain associated with irritable bowel syndrome. This is a small molecule therapy – drugs in this class are based on molecules that have low molecular mass, which allows them to enter and exit cells with relative ease.

The drug is designed to inhibit the activity NHE3, a sodium-hydrogen transporter protein found in high concentrations in intestinal cells. The primary function of NHE3 is to balance sodium levels, which can, of course, have implications in digestion.

The FDA approval of the drug earlier this month was based on impressive results from two randomized, placebo-controlled phase 3 trials of the drug’s efficacy in adult IBS patients with constipation. In these trials, the drug was found to bring about statistically significant improvements in patients’ constipation and abdominal pain when compared to placebo. In the first trial, 37% of participants in the Ibsrela group enjoyed significantly improved bowel movement regularity and reduced frequency of abdominal pain versus only 24% of the placebo group. In the second trial, 27% in the active group improved similarly, versus only 19% of the control group.

“[The FDA approval] represents the culmination of years of dedication to advancing our discoveries and medicines in an effective and rigorous manner.,” said Ardelyx CEO Mike Raab. The new therapy offers physicians and IBS patients a novel way of treating the condition.


Ardelyx is another possible treatment for the over 11 million Americans that have IBS. What do you think of this exciting announcement? Share your thoughts with Patient Worthy!

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