Wellcome Trust support for Drinkable Typhoid Vaccine Programme
Mar 31, 2005, 21:22, Reviewed by: Dr.
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�Typhoid is almost untreatable in parts of Viet Nam because of drug resistance. Therefore an easy-to-use vaccine like this could be of tremendous value in preventing infection in parts of the world where typhoid remains such an important disease.�
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By Wellcome Trust, UK,
Microscience PLC announces that it has been awarded a Wellcome Trust Strategic Translation Award (STA) of �1.95 million to advance the clinical development of Microscience's drinkable typhoid vaccine programme. This is the largest single STA ever made by the Wellcome Trust.
Wellcome Trust STAs aim to provide vital financial bridging for important healthcare programmes and are awarded to researchers in fields of strategic importance to the Wellcome Trust and that address major unmet healthcare needs. The Microscience single-dose drinkable vaccine targets a significant medical need for both travellers to typhoid-endemic areas and the endemic population in large areas of the developing world.
Beginning in early 2005, Microscience, with this financial support from the Wellcome Trust, will undertake the next stage of the Phase II clinical development programme of its oral typhoid vaccine, set up a surveillance programme to determine demographics and disease prevalence in the region and prepare the field-site for the Phase III efficacy study. As the incidence of disease in typhoid endemic regions tends to be most prevalent in children, this population will form a key element of the Phase III efficacy study.
The programme will be undertaken in conjunction with the Hospital for Tropical Diseases in Ho Chi Minh City, Viet Nam and Oxford University, UK. This long-standing collaboration focusing on infectious diseases important in Viet Nam has been funded by the Wellcome Trust since 1991.
The first study will evaluate safety and immunogenicity in adult volunteers in a controlled setting in Ho Chi Minh City and is planned to commence during the first half of 2005. Following the completion of this study, a series of age-descending Phase II studies will be carried out prior to the large-scale Phase III field study.
Previous trials with this drinkable vaccine in over 100 subjects in the US and UK showed it to be highly immunogenic at a single dose with a good safety profile.
Rod Richards, Chief Executive Officer of Microscience, commented:
"The sizeable grant awarded to Microscience by the Wellcome Trust is a clear recognition of the need for a new and effective typhoid vaccine and a significant endorsement of our proprietary approach. The STA investment and collaboration gives us the momentum needed to move into large-scale field studies. It will enable us to pursue a clear path to commercialisation for our typhoid vaccine, with the potential to address healthcare needs for both tourists and business travellers from Europe and North America as well as the needs of the developing world."
Dr. Jeremy Farrar, Director of the Oxford University-Wellcome Trust Clinical Research Unit in Viet Nam, said:
�Typhoid is almost untreatable in parts of Viet Nam because of drug resistance. Therefore an easy-to-use vaccine like this could be of tremendous value in preventing infection in parts of the world where typhoid remains such an important disease.�
Dr Ted Bianco, Director of the Wellcome Trust�s Technology Transfer Division said:
�Our ultimate goal is to translate research into better healthcare and to facilitate the dissemination of new technologies to maximise the benefit to society globally. This vaccine trial is an excellent example of how we can assist in the development of a promising new product with a view to exploring its usefulness in areas beyond the main commercial markets but where the disease is a particular problem.� 
- Wellcome Trust, UK
www.wellcome.ac.uk
Typhoid is caused by the Salmonella typhi bacterium and is transmitted via contaminated drinking water or food. Infection typically causes sustained fever, headache, constipation, malaise, stomach pains, anorexia and myalgia. In severe cases, patients experience confusion, delirium and intestinal perforation, leading to death in some cases.
According to World Health Organisation estimates, between 17 and 33 million cases of typhoid fever occur annually worldwide. Travellers to endemic typhoid areas contract the disease and require urgent medical treatment on their return home (each year approximately 400 US citizens return to the US with typhoid). It is estimated that 600,000 deaths occur annually worldwide, of which 70% occur in Asia.
Current Treatment
Antibiotics are used to treat the disease and usually lead to recovery commencing within four days. Without antibiotic therapy, the mortality rate is up to 30 per cent. In recent years, strains exhibiting resistance to some of the antibiotics have emerged, driving demand for an effective prophylactic vaccine for travellers to "high-risk" areas. There are currently injectible vaccines available however, there is an unmet need and significant opportunity for an efficacious oral, single dose vaccine that would prevent the need for injection.
Microscience Drinkable Typhoid Vaccine
The advent of modern molecular biology techniques has led to the identification of several genes that are essential for the in vivo growth and survival of the organism. This has provided new gene targets for attenuation, leading to the concept that introducing defined non-reverting mutations into selected genes known to be involved in virulence can �rationally� attenuate future vaccine strains. This has facilitated the development of an improved vaccine, particularly in terms of increasing the immunogenicity and therefore reducing the number of doses that have to be administered.
Microscience's new single-dose, drinkable, typhoid vaccine contains independently attenuating deletions in two genes, aroC and ssaV. The aroC gene encodes chorismate synthase, an enzyme involved in the biosynthesis of aromatic compounds. aro mutations are well described as being attenuating for Salmonella in humans. The ssaV gene is encoded on Salmonella Pathogenicity Island 2 (SPI-2). SPI-2 encodes a type III secretion system and ssaV is a structural gene encoding part of the secretion apparatus. The deletion of the ssaV gene prevents the bacteria replicating inside the antigen presenting cell.
The Microscience vaccine stimulates not only a systemic antibody response but also unlike injectible typhoid vaccines stimulates an immune response at the mucosal surface in the gut. This is important as this is the first line of defence following exposure to typhoid.
Clinical Development to Date
To date, three clinical studies involving over 100 healthy adult volunteers have been conducted. These studies showed the vaccine to be highly immunogenic, generating both systemic and mucosal responses, at a single dose with a good safety profile. In trials it has been administered in a stable presentation suitable for commercialisation.
Strategic Translation Awards (STAs)
The WT seek collaborations with industry or academia that can achieve commercialization of new technologies and products. Technology Transfer at the Wellcome Trust proactively seek applications from development scientists conducting research in strategic areas who wish to work in partnership with the Trust to achieve the commercial translation of targeted technologies. Collaborating researchers benefit from access to the Wellcome Trust's considerable expertise and networks.
About Microscience
Microscience is a vaccine company which discovers and develops innovative, preventative and therapeutic vaccines through its proprietary technology platforms. The company has a broad portfolio of five clinical stage vaccines that target infectious diseases. These include oral vaccines to protect against Typhoid (Phase II), ETEC Travellers Diarrhoea (completed Phase I), and a therapeutic vaccine to treat Hepatitis B (completed Phase I). Early stage clinical trials for an injectable Meningitis B vaccine and a neonatal Group B Streptococcus vaccine are ongoing. A further oral vaccine programme against the bioterror threat Anthrax is currently completing pre-clinical development. The Company is based in Wokingham, UK.
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