Conference Coverage

Prebiotic in development shows promise for reducing GERD symptoms


A prebiotic therapy in development significantly reduced the number of days per month that people with gastroesophageal reflux disease (GERD) experienced heartburn.

The prebiotic treatment, maltosyl-isomalto-oligosaccharides (MIMO, ISOT-101), under development by ISOThrive, was also associated with reduced symptom severity and improved quality of life, John Selling, MD, chief medical officer at ISOThrive, said during the presentation of his study at the virtual Digestive Disease Week (DDW) 2021.

ISOT-101 is a nondigestible, nonabsorbable prebiotic carbohydrate produced by bacterial fermentation of sucrose and maltose. It was “possibly a staple of the bacterial diet that was present in the human diet during the past 10,000 years,” Dr. Selling said. He is a clinical associate professor of medicine and gastroenterology at Stanford (Calif.) University.

The prebiotic, however, “has been absent in our diet for about 50 to 100 years, driven by changes in agriculture, food production, food preservation, and dietary preferences,” he added.

Acid suppression treatments, such as proton pump inhibitors (PPIs), have long been a staple of treating GERD. However, about 40% of people taking PPIs still have symptoms, Dr. Selling said. He noted that there are concerns about the health risks associated with long-term PPI use.

A prebiotic could work because the distal esophageal microbiome in people with GERD “differs greatly” from that of healthy persons, Dr. Selling said. The prebiotic could help reduce an abnormal increase in gram-negative bacteria in these patients, for example. These bacterial strains express lipopolysaccharides on their outer cell membranes, which, in turn, alter cytokine signaling. This mechanism could lead to the hyperinflammatory state associated with GERD.

Dr. Selling and colleagues hypothesized that this treatment could help resolve GERD symptoms in two ways. The prebiotic could selectively feed the beneficial gram-positive bacteria in the distal esophagus, thereby helping to restore a healthy balance of bacteria. ISOT-101 could also produce bacteriocins that help kill the harmful gram-negative bacteria and control inflammation.

To assess the efficacy and tolerability of ISOT-101, Dr. Selling and colleagues plan to evaluate use of the agent in 110 people with GERD. The data presented at this year’s DDW are based on the first 44 participants to complete the study protocol.

Participants had to have active symptoms four or more days a week. They verbally reported symptoms to investigators and completed a daily ReQuest validated GERD symptom questionnaire.

After a week of baseline screening, participants consumed about a quarter teaspoon of ISOT-101 as the last substance swallowed before bed every night. The investigators asked participants to rate their GI symptoms, general well-being including any sleep disturbances, and quality of life on the Short Form 36 (SF-36) health survey. Participants also recorded use of any other medications during the 4-week study.

“I thought this was a very interesting study, as it proposes an alternative approach to manage patients with GERD,” Richa Shukla, MD, who was not affiliated with the research, said in an interview when asked to comment. “We see many patients with typical GERD symptoms who do not respond to PPI therapy, and perhaps considering an alternative cause and treatment may help with these patients.”

Dr. Shukla shared a couple of caveats. “This is a relatively small study, and it has not yet completed its enrollment target, so it will be helpful to see what the results are with the full study.” Also, it would be useful to know how many participants also took a PPI during the study, she said.

“Essentially, a lot remains unknown, but the study holds promise for patients,” added Dr. Shukla, assistant professor in the section of gastroenterology and hepatology at Baylor College of Medicine, Houston. “I think there is a lot of interest in the microbiome and how modulating it can impact inflammatory conditions.”


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