Immuron Announces Publication Of Data From Its Phase 2 Clinical Trial Of Once-Daily Oral Travelan In 'Scientific Reports'; Statistically Significant 50% Reduction In ETEC Challenge-Related Adverse Events Versus Placebo

Immuron Limited ((ASX: IMC, NASDAQ:IMRN) today announced that data from its Phase 2 clinical trial of once-daily oral Travelan® has been published in the Nature Journal, Scientific Reports.

A copy of the publication can be accessed here: https://doi.org/10.1038/s41598-026-70974-9

The article titled, "A phase 2, randomized, placebo-controlled study to evaluate once-daily oral Travelan for the prevention of Travellers' Diarrhoea," describes clinical data previously announced to the ASX on March 7, 2024.

The clinical study, partially funded by the U.S. Department of Defense (MTEC Award 21010.13), demonstrated that Travelan® was safe and well tolerated, with a statistically significant 50% reduction in ETEC challenge-related adverse events versus placebo (P=0.0001).

Although the study did not meet its primary efficacy endpoints, a lower than anticipated placebo attack rate (33% versus 70%) materially reduced statistical power. Notwithstanding this limitation, efficacy results consistently trended in favour of Travelan® across multiple clinically meaningful endpoints, supporting the potential protective benefit of the once-daily formulation against ETEC-associated disease.

Key findings

Statistically significant 50% reduction in ETEC challenge-related adverse events versus placebo (P=0.0001)
40% reduction in moderate-to-severe diarrhoea
50% reduction in severe diarrhoea
44% reduction in all diarrhoea
71% reduction in early antibiotic use
Travelan recipients showed attenuated mucosal inflammation four days post-challenge, with lower fecal myeloperoxidase (p=0.04) and calprotectin (p=0.06) than placebo
More than 80% of subjects in both arms seroconverted (IgG/IgA anti-ETEC) by day 15–29, indicating Travelan did not impair natural adaptive immunity to the challenge strain

A further manuscript describing Travelan's effects on the gut microbiome is currently in preparation. Study data demonstrated that Travelan recipients had lower relative abundance of E. coli, enrichment of beneficial bacteria, and greater microbiome richness and diversity compared with placebo. These observations support the potential for Travelan® to enhance gut microbiome resilience during pathogenic challenge and antibiotic exposure, representing an additional mechanism by which the product may contribute to gastrointestinal health.

Immuron is advancing Travelan® as a next-generation, non-antibiotic oral immunoprophylactic for the prevention of bacterial diarrhoeal disease. The program aims to deliver a military-ready, once-daily formulation capable of providing broad-spectrum protection against key pathogens responsible for travellers' diarrhoea and military deployment related gastrointestinal infections.Building on the encouraging findings from the US Government supported clinical study, including a reduction in diarrhea severity and consistently favourable efficacy trends, Immuron has developed a next-generation, delayed-release capsule formulation optimized for once-daily dosing. This novel formulation enables delivery of a substantially higher payload and may be investigated in the larger, adequately powered clinical studies as recommended by the investigators, to further assess its potential to protect against ETEC-associated disease and broader bacterial gastrointestinal infections.

The Naval Medical Research Command and the Walter Reed Army Institute of Research, in collaboration with Immuron, are also progressing the development of novel vaccines targeting Campylobacter jejuni and Shigella sonnei.

Immuron continues to recommend a dose of 1-2 Travelan tablets, three times daily, based on the clinical efficacy observed in previous studies using this regimen, with protection rates of 58.3% (p=0.02), 76.7% (p=0.007) and 90.9% (p=0.0005) (Otto et al., 2011).