Immuron’s Travelan® protects against Shigella in primates

Microbiome biopharmaceutical group, Immuron Limited (ASX:IMC | NASDQ:IMRN), this morning updated the market on its collaborative research and development agreements with the US Department of Defense (US DoD).

The US DoD commissioned several studies to characterise the antibodies within Travelan® — IMC’s commercially available flagship over-the-counter gastrointestinal and digestive health supplement.

The Travelan product is an orally administered passive immunotherapy that prophylactically reduces the likelihood of contracting travellers’ diarrhoea.

The aim here was to conduct trials to determine the product’s effectiveness in neutralising pathogenic gastrointestinal bacterial infections as a preventative treatment for US military personnel and civilians stationed or traveling in locations where such infections could be debilitating.

The US Armed Forces Research Institute of Medical Sciences (AFRIMS), an overseas laboratory of the Walter Reed Army Institute of Research (WRAIR), located in Bangkok, conducted the study that evaluated the therapeutic potential of Travelan in a non-human primate (NHP) preclinical challenge model that closely mimics the disease seen in humans.

This study was performed in collaboration with the Department of Enteric Diseases and the Department of Veterinary Medicine, AFRIMS, and the Department of Enteric Infections, Bacterial Diseases Branch, WRAIR.

The placebo-controlled study was carried out in 12 NHPs segregated into two groups: a Travelan treatment cohort of eight and a placebo cohort of four, which were treated with either Travelan or placebo respectively twice daily for a total of 12 doses over a six-day period.

The animals received treatment for three days prior to oral challenge with ~3 x 109 viable Shigella flexneri strain 2a organisms.

All (4 of 4 - 100%) placebo-treated animals displayed acute dysentery symptoms within 24 – 36 hours of Shigella flexneri 2a challenge. A single (1 of 8 – 12.5%) of the Travelan-treated cohort displayed dysentery symptoms at this time point.

The remaining individuals (7 of 8 – 87.5%) in the Travelan treatment cohort remained symptom-free to 4-days post Shigella flexneri 2a challenge. Once the treatment period was concluded, a second individual in the Travelan treatment group developed symptoms (2 of 8 - 25%).

The remainder (6 of 8 - 75%) of the Travelan treated cohort remained symptom-free to the conclusion of the study 11-days post Shigella flexneri 2a challenge.

Of course, it should be noted that Immuron is still a speculative stock and anything can happen. Investors should seek professional financial advice if considering this stock for their portfolio.

The global burden of diarrhoeal diseases outweighs any of the more complex diseases seen in gastroenterology clinics. Every year, there are an estimated 1.5 billion episodes of diarrhoea worldwide. These episodes result in the deaths of approximately 2.2 million people — mostly children in developing countries.

Unsurprisingly, a preventative treatment that protects against enteric diseases — specifically Shigella — is a high priority objective for the US Army.

Shigella is estimated to cause 80 –165 million cases of disease worldwide, resulting in 600,000 deaths each year, and is particularly prevalent in both sub-Saharan Africa and South Asia.

Dr. Jerry Kanellos, Immuron CEO, said: “Travelan was designed to target selected surface antigens from the most common strains of Enterotoxigenic E. coli (ETEC), bacteria which play a dominant and causative role in Traveler’s diarrhea. Previous studies found several of these antigens are shared with bacillary dysentery-causing organisms such as Shigella species.”

“The work completed at AFRIMS highlighted for the first time that in a preclinical NHP challenge model of shigellosis (also known as bacillary dysentery), Travelan protected 75% of the animals from clinical bacillary dysentery. All the placebo-treated animals displayed classic dysentery symptoms after challenge with a virulent strain of Shigella sp. It is also very interesting to note the second case of dysentery in the Travelan cohort developed once the treatment terminated.”

Dr. Robert Kaminski, Chief of Subunit Enteric Vaccines and Immunology, Department of Enteric Infections, Bacterial Diseases Branch, WRAIR, commented: “The results from this study are very exciting and provide a positive signal for future investigations.

“We received funding to evaluate the Immuron Travelan product for cross-reactivity with Campylobacter, other ETEC strains, and Shigella using in vitro and in vivo methodologies. Our in vitro data set clearly indicated that antibodies in the product cross react with all bacterial pathogens tested.”

“More recently, the NHP study completed at AFRIMS demonstrated that Travelan protects against shigellosis/dysentery in the model. All the animals treated with placebo and then challenged with Shigella flexneri 2a, 2457T became infected and had severe dysentery. Only 25% of the animals (2 of 8) treated with Travelan and then challenged with S. flexneri 2a, 2457T had any constitutional/clinical symptoms. The results from this study, in combination with the results from the in vitro assays, suggest that the Travelan product offers protection/cross reactivity from Shigella,” noted Kaminski.

“The results go some way in confirming that Travelan is effective across all strains and species of enteropathogenic bacteria tested. They significantly strengthen and extend previous results that demonstrated the specificity of antibodies incorporated into Travelan cross-react with multiple enteric pathogens, including Campylobacter, ETEC, Klebsiella, Salmonella and Shigella strains.”

“The current study demonstrates that the Travelan product is functionally cross-reactive and prophylactically effective and confirms that Travelan has a substantially broader spectrum of antimicrobial action than previously reported. These results offer a pathway to further testing which could lead to a major new preventative modality for the US DoD,” Kanellos added.