Sanofi Pasteur, the vaccines division of sanofi-aventis Group, announced that it is sponsoring a phase II clinical study of a vaccine against Clostridium difficile, which is among the most common causes of hospital-acquired infection in Europe and North America.
The trial currently conducted in the United Kingdom is investigating the safety and efficacy of sanofi pasteur's C. difficile candidate vaccine. While the target indication for the vaccine is primary prevention of C. difficile infection (CDI), this trial in infected patients aims at providing early proof of concept of the vaccine approach.
"Treatment of C. difficile infection includes the use of one of two antibiotics. Non-antibiotic approaches for managing C. difficile infection are badly needed since the alteration of the gut flora associated with antibiotics triggers the infection in the first place. There is also considerable concern about the emergence of antibiotic-resistance in C. difficile and other bacteria. Vaccination has the potential to be a very effective strategy to combat gastrointestinal pathologies caused by C. diff. along with better antibiotic stewardship and infection control practices," said Barry Cookson, director, laboratory of healthcare associated infections, Centre for Infections, Health Protection Agency and the lead investigator of the trial.
Sanofi Pasteur's candidate vaccine uses a toxoid-based approach, which has been used extensively in sanofi pasteur's licensed vaccines against tetanus, diphtheria and pertussis (whooping cough). This candidate vaccine has successfully completed phase I clinical trials in more than 200 participants to evaluate its safety and immunogenicity.
The incidence of CDI has increased significantly in recent years in both North America and Europe. CDI-related treatments in these two regions of the world are estimated to be costing more than $7 billion a year. The emergence of a hyper-virulent strain of C. difficile in 2002 further highlighted the importance of tackling CDI.
The phase IIb trial involves about 600 participants with acute CDI at about 30 centres across the United Kingdom. Participants will be randomized to 4 study groups, where three groups will receive vaccine, while the fourth group will be given a placebo vaccine. All subjects will receive standard of care antibiotics.
C. difficile is an anaerobic spore-forming bacterium, present asymptomatically in approximately 60 per cent of infants but only about 3 per cent of healthy adults. It belongs to the Clostridium family of bacteria, which also includes C. tetani (tetanus) and C. botulinum (botulism). The C. difficile bacteria produce two potent toxins: A and B. When the natural microbial flora of the gut is disturbed, usually as a result of antibiotic treatment, and a patient ingests C. difficile spores, the bacteria can multiply and release the two toxins, which cause gastrointestinal pathologies in humans known collectively as CDI.
Hospital-acquired infections caused by C. difficile bacteria are a considerable problem in many industrialized countries, including the US, Canada, and Europe. It is estimated that C. difficile causes about 500,000 cases in the US alone with annual costs to the healthcare system of $3.2 billion. In the EU, assuming a population of about 460 million people, the healthcare costs of CDI are estimated to be around $4.4 billion per year.
Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provided more than 1.6 billion doses of vaccine in 2008, making it possible to immunize more than 500 million people across the globe. A world leader in the vaccine industry, sanofi pasteur offers the broadest range of vaccines protecting against 20 infectious diseases.