Acambis plc, (ACAM), a biotechnology company, has commenced a paediatric clinical trial of ChimeriVax-JE, its investigational single-dose vaccine against Japanese encephalitis (JE). The trial is being conducted in India in collaboration with Bharat Biotech International Ltd. ChimeriVax-JE is being developed to provide a safe, affordable, single-dose JE vaccine for travellers and those living in JE-endemic regions. It is a live, attenuated, injectable vaccine and was developed using Acambis' proprietary ChimeriVax technology, which was developed in association with St Louis University.

As per the company information, the paediatric trial of ChimeriVax-JE is a multi-centre randomised, double blind, controlled study and will be conducted in healthy children and infants. The trial aims to evaluate the safety and immunogenicity of one dose of ChimeriVax-JE compared to two doses of inactivated mouse-brain JE vaccine produced in India.

In addition, concurrent vaccination of ChimeriVax-JE and measles vaccine will be investigated in the target age group for immunization. The target group consists of children aged between nine months and two years, a company press release said.

Earlier, in November 2006, Acambis had announced positive safety results from pivotal phase 3 trials of ChimeriVax-JE, as well as promising preliminary results from the phase 3 efficacy trials.

JE is a virus spread by mosquitoes and is the leading cause of childhood encephalitis and viral encephalitis in Asia. The trial will be first of its kind to be tested in children, who are at the greatest risk from JE in endemic regions, a company press release said.

An estimated three billion people live in JE-endemic regions, including Thailand, China, Japan, India and parts of Australia. Yearly, an estimated 30,000 to 50,000 cases of JE are reported, out of which approximately 25-30 per cent of are fatal. More over, a high proportion of survivors are left with serious neurological impairment, the press release noted.

Despite the availability of first-generation JE vaccines for 60 years, the virus continues to cause death and disease. As a result of this significant unmet public health need, both the World Health Organization's initiative for vaccine research and the gates foundation have identified the need for development of a second-generation, affordable JE vaccine that has an acceptable safety profile and requires fewer doses than currently available vaccines.

The company said, to address this need, it has developed ChimeriVax-JE, an affordable, single-dose JE vaccine with a good safety profile. The introduction of a single-dose vaccine could potentially transform the use of vaccines against JE by making it simpler, faster, easier and cheaper for healthcare providers to administer, particularly in regions like India where achieving compliance to multi-dose regimens can be difficult.

"ChimeriVax-JE has already been tested in approximately 2,400 adult volunteers and we are excited to begin our first paediatric trial in India, a country with JE-endemic that is in great need of a safe, single-dose, affordable vaccine to prevent this dreadful disease. We are committed to meeting this need with ChimeriVax-JE and the start of this trial brings us one step closer to achieving this important goal," said Gordon Cameron, chief executive officer of Acambis.

Once approved, Bharat Biotech International Ltd, the company's partner, will market and distribute the ChimeriVax-JE in India and neighbouring countries. Bharat Biotech will also be responsible for end-stage fill/finish processing of ChimeriVax-JE at its facilities in India.

"The JE epidemic in 2005, which claimed the lives of more than 1,300 children in Northern India and Nepal, showed the devastating effects of JE and the need for vaccination. Under our partnership with Acambis, we aim to make it easier for children in the Indian subcontinent to be protected against this terrible disease by providing them with a safer, affordable JE vaccine that requires only one dose for immunity, " said Krishna M Ella, chairman and managing director of Bharat Biotech International Ltd.