Safety and efficacy of purified clinoptilolite-tuff treatment in patients with irritable bowel syndrome with diarrhea: Randomized controlled trial.

Background: Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder with poor response to treatment. IBS with predominant diarrhea (IBS-D) is accompanied by abdominal pain as well as high stool frequency and urgency. Purified clinoptilolite-tuff (PCT), which is approved by the Food and Drug Administration for use as a dietary supplement with the brand name G-PUR, has previously shown therapeutic potential in other indications based on its physical adsorption capacity.

Aim: To assess whether symptoms of IBS-D can be ameliorated by oral treatment with PCT.

Methods: In this randomized, placebo-controlled, double-blind pilot study, 30 patients with IBS-D diagnosis based on Rome IV criteria were enrolled. Following a 4-wk run-in phase, 14 patients were randomized to receive a 12-wk treatment with G-PUR (2 g three times daily), and 16 patients received placebo. The relief from IBS-D symptoms as measured by the proportion of responders according to the Subject's Global Assessment (SGA) of Relief was assessed as the primary outcome. For the secondary outcomes, validated IBS-D associated symptom questionnaires, exploratory biomarkers and microbiome data were collected.

Results: The proportions of SGA of Relief responders after 12 wk were comparable in both groups, namely 21% in the G-PUR group and 25% in the placebo group. After 4 wk of treatment, 36% of patients in the G-PUR group 0% in the placebo group reported complete or considerable relief. An improvement in daily abdominal pain was noted in 94% 83% ( = 0.0353), and the median number of days with diarrhea week decreased by 2.4 d 0.3 d in the G-PUR and placebo groups, respectively. Positive trends were observed for 50% of responders in the Bristol Stool Form Scale. Positive trends were also noted for combined abdominal pain and stool consistency response and the Perceived Stress Questionnaire score. Only 64% in the G-PUR group compared to 86% in the placebo group required rescue medication intake during the study. Stool microbiome studies showed a minor increase in diversity in the G-PUR group but not in the placebo group. No PCT-related serious adverse events were reported.

Conclusion: In this randomized, double-blind, placebo-controlled study, the PCT product, G-PUR, demonstrated safety and clinical benefit towards some symptoms of IBS-D, representing a promising novel treatment option for these patients.