Introduction 

A recent, single-site, randomised, double-blind, placebo-controlled, phase 2 trial has been conducted to assess the efficacy and safety of benralizumab, an eosinophil-depleting monoclonal antibody, in patients with eosinophilic gastritis.

Eosinophilic gastritis is characterised by a high count of eosinophils, a type of white blood cell in the stomach lining. Understanding the impact of eosinophils in the pathogenesis of eosinophilic gastrointestinal diseases and their effect on patient outcomes has been a key area of study.

Similar studies have been conducted earlier, supporting the conclusion the reduction of eosinophils alone, i.e. histological remission, does not necessarily lead to symptom improvement in some patients.

Beginning of phase 3 trial on Fasenra in EoE

First UK Patient on Messina Trial

The update on Messina Trial

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Trial Design and Methods

The phase 2 trial was conducted at Cincinnati Children's Hospital Medical Centre, focusing exclusively on individuals aged between 12 and 60 years with symptomatic, histologically active eosinophilic gastritis.

The 26 participants (19 males (73%) and 7 females (27%), with an average age of 19.5 years) were randomly assigned to receive either a 30 mg dose of benralizumab or a placebo.

The assignments were stratified by the use of glucocorticoids for gastric disease, ensuring a balanced representation of disease severity in both the treatment and control groups.

Treatments were administered subcutaneously once every four weeks for a 12-week double-blind period (three total injections), after which patients were eligible for two open-label extension periods where all patients received benralizumab.

Key Findings

The study's primary endpoint was the proportion of patients who achieved histological remission at week 12, defined as a peak gastric eosinophil count of fewer than 30 eosinophils per high-power field. 

The trial found that 77% of patients receiving benralizumab achieved histological remission at week 12, compared to 8% in the placebo group.

Moreover, significant changes were observed from baseline to week 12 in peak gastric eosinophil counts, eosinophilic gastritis histology total score, inflammatory histology score, and blood eosinophil count in the benralizumab group compared to the placebo group.

But changes were not significantly different between the groups for eosinophilic gastritis histology structural score, EG-REFS score, or in the symptoms etc., in patient-reported outcomes (SODA and PROMIS).

Safety and Adverse Events

Throughout the double-blind period, treatment-emergent adverse events occurred in 85% of patients in the benralizumab group and 46% in the placebo group. The most common adverse events were headache, nausea, and vomiting.

Interpretation and Future Directions

The trial concluded that benralizumab treatment induced histological remission in most patients with eosinophilic gastritis, demonstrating its potential as a promising therapeutic strategy for some patients.

However, the persistence of histological, endoscopic, and other disease features post-treatment suggests an eosinophil-independent pathogenic mechanism. This is due to the recognition that eosinophils, while significant, may not definitively signal a patient's remission. 

This underscores the need for more research on different immunity pathways in future research and treatment strategies.

There is an urgent need for other biomarkers beyond eosinophils. This could provide a more nuanced understanding of the disease's progression and treatment response and enable more personalised and effective treatment strategies.

Funding

AstraZeneca and the Division of Intramural Research of the National Institute of Allergy and Infectious Diseases, US National Institutes of Health, funded this trial.

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