Sanofi’s C diff vaccine fast tracked by FDA
A new vaccine aimed at preventing C difficile infections has been fast tracked by the FDA.
The regulator’s decision signals that the treatment, being developed by Sanofi Pasteur, could be a breakthrough in an area of unmet medical need.
Cases of Clostridium difficile infections (CDI) have surged in recent years in North America and Europe, and are the most common cause of hospital-acquired infection.
Current treatment of C. diff infection involves the use of one of the two antibiotics recommended for CDI management, but the emergence of virulent and drug resistant strains are a major cause for concern.
There are an estimated 500,000 cases of CDI in the US every year, with annual costs to the healthcare system of $3.2 billion. In the EU the healthcare costs of CDI are estimated to be around $4.4 billion per year.
Deaths caused by hospital acquired infections have hit the headlines in the UK in recent years, and NHS trusts must now keep a record of cases and have a plan to prevent infections. Around 12,000 cases were recorded in England in the 12 months to August 2010.
The new vaccine uses a ‘toxoid’ or weakened version of the C difficile bacterial toxin to stimulate an immune defense against a future infection. The approach is a well-established technique in vaccines, which could help the FDA approve the drug speedily.
Because the vaccine is not an antibiotic, it also avoids the increasing problem of antibiotic-resistance in the C difficile.
“Our C. difficile vaccine candidate is in phase II,” according to Michel DeWilde, senior vice president, Research and Development at Sanofi Pasteur.
“The FDA fast-track designation recognises that a C. difficile vaccine could address an important unmet medical need. Under this programme,” he explained, “the FDA can accept for review completed portions of the licensing application prior to receipt of the entire application.”
Other companies are also pursuing new treatments for the infection. Medarex and Massachusetts Biologic Laboratory are currently collaborating with Merck on an antibody treatment for C. difficile infection.
C diff and antibiotic treatment
Clostridium difficile is an anaerobic spore-forming bacterium, and is present asymptomatically in approximately 60% of infants but only around 3% of healthy adults.
Infection occurs when the natural microbial flora of the gut are disturbed, usually as a result of antibiotic treatment for other infections, and a patient ingests C difficile spores.
The bacteria can multiply and release the two toxins which cause a broad range of gastrointestinal symptoms in humans known collectively as CDI.