Dupilumab Phase 2 Trial Shows Significant Improvements for Eosinophilic Gastritis

A phase 2 clinical trial has shown that the monoclonal antibody dupilumab produces significant improvements for patients with eosinophilic gastritis, a rare inflammatory food-allergic disease of the stomach. The study, known as the Dupilumab Eosinophilic Gastritis Study (DEGAS), was published on June 23, 2026, in The Lancet Gastroenterology & Hepatology.

The trial, conducted by the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR), involved 41 teens and adults with active EoG across 11 U.S. medical centers. Participants were randomly assigned to receive dupilumab or a placebo for 12 weeks. After that initial period, all participants received dupilumab during an open-label extension.

Those who received dupilumab instead of a placebo during the first 12 weeks showed significant improvements in objective measures. This included reduced stomach eosinophil counts, improved results from endoscopy exams, and improved scores on pathology of stomach tissue samples. These tissue-level improvements continued through 36 weeks, and the safety profile was consistent with prior studies of dupilumab.

Dupilumab works by stopping signaling from interleukin-4 and interleukin-13, key cytokines involved in type 2 inflammation. The medication was first approved in 2017 as a treatment for adult atopic dermatitis (eczema). Since then, it has been approved for eight more conditions, including eosinophilic esophagitis (EoE). Dupilumab received initial approval for EoE in 2022, which was extended in 2024 to include children as young as 1 year old, weighing at least 15 kilograms.

Eosinophilic gastritis causes severe stomach reactions to common foods, including dairy, wheat, gluten, egg, soy, fish, and nuts. Symptoms include nausea, vomiting, abdominal pain, and fatigue. There are currently no approved medications to slow the inflammatory allergic response in the stomach. The latest data estimate that EoG occurs in an estimated 5 to 7 people in a population of 100,000, making it about 10 times less common than EoE, which affects up to 500,000 people in the U.S.

The study represents a major step forward for potentially helping people with EoG while also illustrating the challenges involved in developing treatments for very rare diseases. For many rare diseases, the small numbers of affected people make it extremely difficult for pharmaceutical companies to conduct the clinical studies needed to secure U.S. FDA approval. However, for some conditions, investigating an already-approved therapy in a new disease setting can become a vital pathway to improved outcomes. This approach could potentially serve as a model to address EoG and other rare diseases.