Acambis commences C. difficile vaccine trial
vaccine against Clostridium difficile (C. difficile) - a common
hospital-acquired infection, in which a new virulent strain has
emerged, causing sharp increases in the number of infections and
associated deaths worldwide.
C. difficile caused 43,000 infections in the UK alone in 2004, a 23 per cent increase over the previous year. C. difficile infections also cause approximately 350,000 cases every year in the US and most of these involve elderly individuals who become infected in hospitals and long-term care facilities that have become breeding grounds of this organism.
A highly virulent strain of C. difficile has resulted in outbreaks in 15 hospitals in the UK. At Stoke Mandeville Hospital in Buckinghamshire alone, this strain caused 12 deaths and infected 300 patients. C. difficile infections also reached epidemic proportions in Quebec, Canada, where the number of C. difficile cases doubled and the fatality rate increased by 60 per cent between March 2000 and April 2004.
Results from the CDC and from the Anaerobe Reference Laboratory in the UK confirm that an emerging strain is responsible for recent and ongoing outbreaks associated with severe disease in the UK, Canada, the Netherlands and the US.
The Phase I trial is designed to test safety, tolerability and immunogenicity of Acambis' C. difficile vaccine when administered at different dose levels. The randomised, double-blind, placebo-controlled study in healthy adult subjects is being conducted at two study centres in the US. Acambis also plans to start a second Phase I trial of its C. difficile vaccine in elderly subjects.
Currently, no vaccine exists to protect individuals against C. difficile. Acambis has been developing a C. difficile vaccine for many years and has spent the last two years improving and optimising the formulation of the vaccine. They are the only company known to be developing a vaccine against it. Its investigational toxoid vaccine was developed to provide immunity against toxins A and B, the toxins responsible for the development of C. difficile-associated diarrhoea.
Commenting on the threat of the C. difficile infection, which is characterised by diarrhoea and colitis, Dr Thomas Monath, chief scientific officer of Acambis, said: "C. difficile has long been a problem for hospitals but with the emergence of the new virulent strain the number of outbreaks in hospitals is rapidly increasing, resulting in higher numbers of infection and death."
"There is currently no effective means of preventing future outbreaks of C. difficile. Acambis is the only known company developing a vaccine to protect against C. difficile infection and we are pleased to have entered the important clinical testing development stage," he added.
Gordon Cameron, chief executive officer, said the estimated cost of C. difficile infections costs the UK NHS alone more than £200 million a year because of extended hospital stays, which can be up to three weeks for elderly patients.
"C. difficile is a burden to hospitals and long-term care facilities and a cause of increasing anxiety for patients entering hospitals. There is clearly a substantial need for an effective way to prevent C. difficile infection."
In April, Michel Warny, director of bacterial process development at Acambis, presented findings at the Society for Healthcare Epidemiology of America conference, which revealed this emerging strain produced approximately 20 times more toxins than the majority of clinical isolates.
The news of Acambis' intentions is encouraging. The hospital infections market is growing so this is potentially a very good product to have. Adding to the fact that other companies aren't yet developing rival products. Drugs making it to this stage have 15-18 per cent chance of reaching market. However, its status as an early clinical stage candidate means it will reach the market in 2009 by the earliest.
