Streptococcus pneumoniae causes up to a million cases per year of invasive disease in young children and infants, most occurring in developing countries. Pfizer is partnering with WHO and the GAVI alliance to support the developing world on immunization against pneumococcal disease. Prevnar 13™ is currently approved for the prevention of invasive pneumococcal disease in twenty seven countries. If used widely, this pneumococcal conjugate vaccine could prevent hundreds of thousands of additional cases of child mortality each year.
Use of single-dose preservative-free vaccine formulations will raise the overall cost of vaccination programs and may jeopardize the effectiveness of immunization programs in developing countries. Multi-dose vials lower the cost for each vaccination but typically need to include a preservative to prevent contamination that might be introduced during the withdrawal of vaccine doses from such vials. To develop a multi-dose formulation of Prevnar 13™ for the developing world, a preservative effective in meeting antimicrobial efficacy test requirements, that would maintain vaccine stability, and have an established safety record in infants was required.
Multiple preservatives which include phenol, 2-phenoxyethanol (2-PE), meta-cresol, methylparaben and propyl paraben and thimerosal (as a control) were evaluated as potential candidates for a multi-dose formulation of Prevenar 13 based on preservative effectiveness and product stability. 2-PE showed superior antimicrobial effectiveness in Prevnar 13 formulations as per European Pharmacopoeia (EP) requirements and in multiple challenge studies with various organisms, as per WHO Open Vial Policy, to mimic worst case inadvertent microbial contamination that might occur during immunization of subjects when the formulation is presented in multi-dose vials. Prevnar 13 in the presence of 5mg dose of 2-PE is stable for over two years and meets the preservative effectiveness standards based on the EP 5.1.3 as well as WHO multi-organism challenge test. The data support the use of 2-PE as a more effective preservative with the potential to replace thimerosal, the most commonly used preservative in multi-dose vaccine formulations
