CAMBRIDGE, England and CAMBRIDGE, Massachusetts, March 21 /PRNewswire-FirstCall/ -- Acambis plc (Acambis) announces that clinical testing of its investigational West Nile virus vaccine, ChimeriVax(TM)-West Nile, is underway in older adults, those most in need of protection against West Nile virus infection. Acambis' ChimeriVax-West Nile is the most advanced West Nile virus vaccine in development and the first to be tested in older adults.
According to the Centers for Disease Control and Prevention, people over the age of 50 are more likely to develop serious symptoms from West Nile virus infection; however, individuals of all ages living in areas where West Nile virus has been identified are at risk. West Nile virus continues to be a high-profile problem in the US, causing 4,256 cases and 165 deaths in 2006. This is a more than 41% increase in the number of cases and 38% increase in deaths compared with 2005.
Acambis' Chief Executive Officer Gordon Cameron commented: "The significant increase in the number of cases and deaths from West Nile virus last year reinforces the need for a protective human vaccine. Acambis is the leader in developing a West Nile virus vaccine and we've taken another important step by testing ChimerVax-West Nile in older adults, the group most at risk of severe disease from West Nile virus infection."
The trial is designed to evaluate the safety, tolerability and immunogenicity of ChimeriVax-West Nile in older adults and is being conducted in the US. The randomised, double-blind, placebo-controlled study is the second part of a Phase 2 trial evaluating the vaccine.
Previously, Acambis announced encouraging results from the first part of the Phase 2 trial, which involved younger adults aged 18-40 years. Over 97% of subjects who received a single dose of ChimeriVax-West Nile developed neutralising antibodies above the predefined cut-off level 28 days after vaccination. The majority of adverse events were mild in nature.
ChimeriVax-West Nile is being developed to provide a safe, single-dose West Nile virus vaccine for at-risk individuals. There is currently no human vaccine against this disease so efforts to reduce the incidence of infection revolve around preventive measures to protect against mosquito bites, the cause of nearly all human infections of the virus.
While the majority of West Nile infections are mild and asymptomatic, approximately 20% of those infected will develop symptoms such as fever, headache, body aches and swollen glands. The more severe West Nile encephalitis is estimated to occur in one out of every 150 infections. Symptoms include high fever, neck stiffness, stupor, convulsions, coma and sometimes paralysis. Death can occur in the most severe cases when the virus crosses the blood-brain barrier, leading to encephalitis or inflammation of the brain.
Since the West Nile virus emerged in the US in 1999, there have been almost 24,000 cases and 946 deaths.
Notes to Editors:
About ChimeriVax-West Nile
- ChimeriVax-West Nile is being developed to provide a safe, single-dose West Nile virus vaccine for those at risk from the virus.
- Development of Acambis' investigational vaccine, ChimeriVax-West Nile, was supported by a $3m grant from the US National Institutes of Health.
- It is a live, attenuated, injectable vaccine and was developed using Acambis' proprietary ChimeriVax(TM) technology, which was developed in association with St Louis University.
- The level of immune response required for protection against West Nile virus is yet to be determined.
About Acambis
Acambis is a leading biotechnology company targeting infectious diseases with novel vaccines. Acambis' development-stage pipeline includes vaccines that could either offer improvements over existing products or target unmet medical needs. As well as ChimeriVax-JE, Acambis' proprietary ChimeriVax technology has also been used to develop ChimeriVax-West Nile, which is undergoing Phase 2 clinical testing, making it the most advanced investigational vaccine against the West Nile virus. Acambis also has the only vaccine in development against Clostridium difficile bacteria, a leading cause of hospital-acquired infections. Recognised internationally as the leading producer of smallpox vaccines, Acambis is developing an investigational smallpox vaccine, ACAM2000, and is manufacturing emergency-use stockpiles of this investigational vaccine for the US Government and other governments around the world.
Acambis is based in Cambridge, UK and Cambridge, Massachusetts, US, and is listed on the London Stock Exchange (ACM). More information is available at http://www.acambis.com/.
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The statements in this news release that are not historical facts are forward-looking statements that involve risks and uncertainties, including the timing and results of clinical trials, product development, manufacturing and commercialisation risks, the risks of satisfying the regulatory approval process in a timely manner, the need for and the availability of additional capital. For a discussion of these and other risks and uncertainties see "Risk management' in the Company's 2005 Annual Report and "Risk factors' in its Form 20-F, in addition to those detailed on the Company's website and in the Company's filings made with the Securities and Exchange Commission from time to time. These forward-looking statements are based on estimates and assumptions made by the management of Acambis and are believed to be reasonable, though are inherently uncertain and difficult to predict. Actual results or experience could differ materially from the forward-looking statements.
