Tuesday, October 09, 2012

Trial Suggests Prevnar May Also Protect Ages 18 to 49

(Reuters) Oct 05 - Pfizer Inc said a late-stage trial of its vaccine to protect against pneumococcal pneumonia suggested it would also work in adults aged 18-49, thereby possibly expanding its sales.
The vaccine, Prevnar 13, which already has $3.5 billion in annual sales from its use in adults over age 50 and children under age five, is designed to protect against pneumonia, meningitis and other infections caused by 13 strains of Streptococcus pneumoniae.
Pfizer said Prevnar 13 met the main goal of the late-stage study by showing that the immune response to the vaccine in the 18- to 49-year-old age group was not inferior when compared with the response in the 60-to 64-year-old group.
Pfizer said on Thursday that the favorable results from the study will support both its recent European Union application to market the product for the 18-49 age group, as well as applications it plans to make in other countries.
A competing vaccine from GlaxoSmithKline, Synflorix, protects against 10 strains of S. pneumoniae.
Commentary: It's always good to know about the clinical effectiveness of a vaccine in a defined age-group. However, two notes of caution are warranted....
1) It is very important to know the disease burden in the defined age group, more so in case of an expensive vaccine like Prevenar, since that would help decide the cost-effectiveness. How commonly do these problems occur in 18-49 year old people? Not very often, in my opinion.
2) The study talks about immune response only, which is NOT the same thing as clinical effectiveness. This means that the antibody responses that are measured do not necessarily result in people being actually protected against these illnesses.
Overall, given that the illnesses that are being protected against (pneumonia, meningitis, sepsis) do not occur frequently in the age group of 18-49 years, and the vaccine is prohibitively expensive, I do not think this study  would have a major impact in developing countries including India.


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