Helicobacter pylori

Helicobacter pylori (H. pylori) is a Gram-negative, microaerophilic bacterium adapted to survive in the stomach of humans. It is estimated that approaching 50% of the world’s population may be infected. Most of these infections are not associated with clinical disease. However, a significant proportion of those infected will go on to develop a range of common problems, including gastritis, peptic ulcer disease, and gastric cancer. Although less than one percent of those infected will develop gastric cancer, it is the fourth most prevalent malignancy in the world. These strong disease associations establish H. pylori as a leading gastroenterological public health problem.

For symptomatic infections, eradication is usually achieved by triple therapy; a combination of two antibiotics, typically clarithromycin, amoxicillin or metronidazole, combined with a proton-pump inhibitor. There are regional guidelines which recommend specific combinations, some of which are directed towards cost issues. However, low-cost options may not be as effective as more expensive regimes and may necessitate repeat treatment, leading to higher costs overall. Metronidazole is also used to treat common enteric infections such as amoebiasis and giardiasis, often empirically. Metronidazole resistance is an increasing problem worldwide, although eradication of infection may be affected more by clarithromycin resistance. Antibiotic resistance is the main reason for treatment failure. Re-infection rates post eradication can be as low as 1% in western countries. However, in developing countries, re-infection rates are markedly higher. Studies from Chile and Bangladesh have found re-infection rates of around 13%.

There are identified needs for both preventative and therapeutic vaccines, with the preventative vaccine aimed primarily at young children from high prevalence areas. ImmBio has an ImmBioVax programme which addresses both the prophylactic and disease management vaccine requirements. ImmBio is collaborating with the Centre for Animal Biotechnology, University of Melbourne, Australia.