VacZine Analytics: Clostridium Difficile - Vaccines Must Be Part Of Future Action Plan, UK

Main Category: MRSA / Drug Resistance
Also Included In: Immune System / Vaccines
Article Date: 07 Dec 2007 - 1:00 PDT

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New studies released by research consultancy, VacZine Analytics suggest that a vaccine could be the most effective weapon against Clostridium difficile, the dangerous hospital "superbug". The development of a vaccine, along with other non-antibiotic approaches must be prioritized as part of any future action plan. The new research puts forward a possible vaccination strategy and confirms there is enough economic incentive for manufacturers to fund development.

Clostridium difficile (C.diff) is a Gram-positive bacterium, which causes gastrointestinal infections in vulnerable hospitalized patients. Outcomes range from mild uncomplicated diarrhea to severe-complicated disease with fever, tachycardia and psuedomembranous colitis. Mortality rates can reach 6-30% however; in patients with toxic megacolon who require surgery rates increase to 35-50%. In the UK, C.diff has been a factor in the death of over 3000 people in 2005 (ONS Figures).

When interviewed, leading experts agreed that C.diff had joined MRSA in being one of the most serious hospital infections they faced. Major concerns were the dramatic yearly rises (10-20%) in incidence and increases in disease severity. These observations reflected official trends stated by US CDC and UK Health Protection Agency (HPA). Although some experts were hopeful C.diff incidence could be reduced, others saw little reason why the problem would decrease without radical developments in prevention. An aging population, insufficient infection control, continued high use of antibiotics and a new strain of C.diff (027/Nap1) were cited as key drivers behind the current "epidemic".

C.diff disease is treated with two antibiotics, either vancomycin or metronidazole. Both treatments are mostly effective but around 20% of patients suffer disease recurrence and need retreatment. Failure rates after retreatment increase to 30-50% with some patients then suffering multiple relapses. Experts agreed that the need for new strategies was highest in this group but when questioned about emerging drug treatments did not expect any great changes in the coming years. They also suggested that biotherapeutics rather than new antibiotics were the way forward.

Inability to prevent disease is also key challenge with C.diff, hence notable hospital outbreaks in the UK and US. If a prevention measure were effective it would importantly reduce reliance on therapy and rates of recurring disease. Experts indicated future possibilities with the toxin-binding agent; Tolevamer (Genzyme) or probiotic agents but a new prophylatic vaccine appeared the strongest option. Scientific evidence has suggested an immunological approach is feasible. However, a vaccine could only be effective if individuals are protected before the greatest risk of C.diff infection e.g. hospitalization.

Dr John Savopoulos who led the research commented, "after modelling different scenarios with experts, the most logical option would be to vaccinate people at highest risk in community so when they enter the hospital they are protected or further boosted. This could be done alongside pneumococcal or influenza vaccines". Dr Savopoulos further stated, "Because the number of vulnerable people is growing, even taking conservative estimates of coverage we estimate the peak opportunity to be around 20 million doses in the seven major markets. Everything points to this being an attractive commercial as well as medical opportunity."

Currently UK-based Acambis have the only C.diff vaccine in development (Phase I). Although there have been technical difficulties with the program VacZine Analytics believes these are not insurmountable. Based on the high profile and unmet medical need associated with C.diff other companies are advised consider this option and begin further C.diff research programs.

http://www.vacZine-analytics.com