PW: What was the purpose of the phase 3 T3MPO-2 study?
Dr. Chey: This was a phase 3 trial for the novel agent tenapanor, which blocks sodium reabsorption from the small intestine, leading to net secretion of water and electrolytes, which offers benefits to constipation-related symptoms. There is also preliminary evidence to suggest that tenapanor improves abdominal symptoms like pain and bloating through effects on calcitonin gene-related peptide-dependent pain mechanisms.
Can you explain more about the study?
This was an adequately powered, rigorously designed phase 3 registration trial using accepted FDA endpoints for patients with IBS-C. Thes T3MPO studies were used as the key evidence of tenapanor’s efficacy for the symptoms of IBS-C in the FDA approval process.
What are the most important findings?
The studies showed that a statistically significantly larger proportion of patients receiving tenapanor achieved the FDA primary endpoint for trials in patients with IBS-C. This endpoint required that patients experience prespecified improvements in abdominal pain and stool frequency. Patients in the trials reported a greater likelihood in improvement of a wide range of constipation and abdominal symptoms with tenapanor compared with placebo.
What are the implications of these findings?
Tenapanor is the first NHE3 inhibitor to be FDA-approved for the treatment of patients with IBS-C and adds to the list of highly effective, evidence-based medical treatments for this challenging-to-treat population of patients.
How does the side-effect profile of tenapanor compare with that of other IBS-C treatments?
The most common side effect was diarrhea, occurring in around 15% of study participants. Most patients reported the diarrhea to be of mild severity.
What do the study findings mean for patients with IBS-C?
It is exciting to have a medication that improves both constipation and abdominal symptoms in patients with IBS-C and does so by a novel mechanism of action.