Dr. Mayo noted that the GI side effects were “consistent with the mechanism of action and localized exposure of the drug in the gut.” Despite having looser stools, she observed that “very few patients wanted to stop treatment for it”.
As for the high placebo response, this is not uncommon in trials, with rates of 20% being previously seen in studies evaluating pain or itching. “There are some interesting theories about what goes on with the placebo effect, it is real and physiologic,” she said.
The study was funded by Lumena (part of the Shire Group of Companies). Dr. Mayo disclosed receiving honoraria or research funding from Gilead Sciences, Intercept Pharmaceuticals, Lumena, NGM Biopharmaceuticals, and Salix Pharmaceuticals.