Added by Erik West on November 15, 2011
The U.S. Food and Drug Administration (FDA) released a report on Monday about the suitability of U.S. drug maker Pfizer’s Prevnar 13 for use in protecting adults over age 50 from pneumococcal infections.
Prevnar, known as Prevenar in Europe and other countries, is being reviewed in the FDAs accelerated approval process, a process reserved for drugs that address unmet medical needs.
The need in this case its efficacy on streptococcus pneumonia, responsible for a range of problems including meningitis, pneumonia and ear infections. Pneumococcal pneumonia is common in older adults and kills thousands each year, according to U.S. Centers Disease Control and Prevention. The currently accepted treatment using Pneumovax by U.S. drug maker Merck is effective only against invasive pneumonia.
Prevnar 13, among the world’s biggest selling vaccines, is currently only approved for use in children aged 6 weeks to 5 years old. Pfeizer says using the vaccine for adults would generate more than US$1.5bn in sales.
Prevnar vaccines are a new generation of pneumococcal vaccines known as Pneumococcal conjugate vaccines (PCV) that’s made using 13 variations of pneumococcus bacterium, conjugated or transferred onto a carrier protein. Previous drugs are capsular polysaccharide vaccines which are effective against the less common invasive pneumonia.
Capsular polysaccharide vaccines were a landmark discovery in medicine and was first proven to be effective by Robert Austrian in 1978. Capsular polysaccharides act as a natural camouflage for some invading bacteria to prevent an immune response. Capsular polysaccharide vaccines help the immune system recognize the ‘camouflage’. In contrast, the newer pneumococcal conjugate vaccines like Prevnar 13 are effective against more bacterium because they use a purified form of the ‘camouflage’. The vaccines cannot cause pneumococcal disease since they contain only aspects of the inactivated bacterium’s outer surface.