Clinical trial results have shown that some strains of the Helicobacter pylori bacteria (H. pylori) are well tolerated in humans and can provide a potential oral delivery platform for vaccines.
Dr. Barry Marshall said the positive results would now see Ondek Pty. Ltd. move to seek approval for another round of clinical trials in which a flu virus gene would be attached to the bacteria. The data also showed which strains of the unique bacteria had the most benign effect on the human stomach while still inducing an immune response.
It may soon be possible to provide a simple oral delivery mechanism for vaccines that can protect against common diseases and be produced, stored and distributed faster and more cheaply. This may one day even make having an annual flu shot as painless as downing a spoon of yogurt.
Researchers at Sir Charles Gairdner Hospital in Perth gave several strains of H. pylori to 30 healthy adults to see how their immune systems responded. The trial had three primary endpoints:
1. Colonization rates (the ideal strain must colonize humans)
a. High colonisation rate for all selected strains
b. Three strains are persistent colonisers
c. Two strains are transient colonisers
2. Safety profile (the ideal strain must have minimal side effects)
a. Generally mild symptoms overall
b. Two strains showed very little / no symptoms
c. One strain showed mild symptoms
d. Two strains associated with clinically significant gastric symptoms
3. Immunogenicity profile
a. All strains induced systemic and mucosal immune responses, sufficient to support a vaccination strategy.
While H. pylori stimulate the body’s immune system to produce antibodies, the bug is capable of evading immune clearance and continues to reproduce in the lining of the stomach.
Ondek plans to use this natural activity as a way of stimulating the human immune system to produce antibodies against diseases such as influenza, where specific antigens can be attached to the H.pylori bacteria by genetic engineering techniques in their labs. They also plan to use this unique approach to develop food-like vaccines that activate an immune response in the body to fight diseases like swine flu, malaria, cholera, hepatitis B and even HIV.
Dr. Marshall was the Australian scientist who identified the cancer-causing stomach bacterium H.pylori and was awarded the 2005 Nobel Prize in Physiology or Medicine along with his research partner Dr. Robin Warren.
Global market background
Dr. Marshall said the global vaccine market was driven by the need to cut the time and cost of making large amounts of vaccines in the face of any potential pandemic.
Current vaccine production methods are expensive and limited by time, volume and capacity. The effectiveness of each new vaccine is also reduced over time due to the changing nature of different viruses.
Governments worldwide spend billions of dollars every year to stockpile drugs and promote pandemic readiness with the global market for vaccines estimated to be worth up to US$40 billion in 2010, according to Pharmaceutical Technology Europe.
Influenza already causes three to five million cases of severe illness each year and up to 500,000 deaths worldwide. The World Health Organisation (WHO) has estimated the annual cost of influenza epidemics in the US economy alone, as up to US$167 billion.
About half of the world’s population is infected with the H. pylori bacteria, according to the WHO. Most people carry the bug without developing symptoms yet it is also the main cause of gastric ulcers and stomach cancers in persons who carry it for 10 and 50 years respectively. Modern science has detected the bacterial factors which cause this risk so that they can be modified or omitted in vaccine strains as required.
