Acambis starts Phase I trial of C. difficile vaccine in elderly subjects

29-11-2005: Acambis plc announced that it has started a Phase I clinical trial of its investigational vaccine against Clostridium difficile (C. difficile) in healthy elderly subjects. This follows an initial Phase I safety and immunogenicity trial in healthy young adults that commenced in July and is the next step in the Company's clinical development plan for this vaccine candidate. C. difficile infection, which is characterised by diarrhoea and colitis, is one of the most common hospital-acquired infections around the world. A hyper-virulent, hyper-toxigenic strain of C. difficile has recently emerged and is believed to be responsible for sharp increases in the number of infections and deaths associated with the infection in countries including the UK, Canada and the US.

The Phase I trial is designed to obtain information on the safety, tolerability and immunogenicity of Acambis' C. difficile vaccine when administered at different dose levels. The randomised, double-blind, placebo-controlled study in healthy elderly subjects is being conducted in the US. Acambis is the only company with a vaccine against C. difficile in clinical development. Its vaccine is designed to provide protective immunity against toxins A and B, the toxins responsible for the development of C. difficile-associated disease (CDAD). The primary market for the vaccine is those most at risk of CDAD, such as the elderly, individuals entering nursing homes and chronic disease sufferers at risk of hospitalisation, and relapsers.