The San Diego based biopharmaceutical company (Vical Inc) recently published a couple of articles (1,2) in a special edition of the Journal "Vaccine" regarding the company's patented adjuvant Vaxfectin (R). They managed to demonstrate in mice that when commercially acquired Sanofi-Pasteur Fluzone (R) - a seasonal trivalent influenza vaccine (TIV) - is formulated with Vaxfectin(R) it managed to produce antibody responses that are 200-fold higher than unadjuvanted seasonal (TIV). Furthermore they also successfully registered a remarkable 10-fold dose-sparing effect. The publication of these data came less than a week after information emerged about apparent hiccups in the manufacturing process of the H1N1 vaccine, during a meeting of experts on the Advisory Committee on Immunization Practices, which makes recommendations to CDC. Production of H1N1 vaccine lagged behind schedule due to vaccine immunogen harvested from chicken eggs falling short of expected yields, with some manufacturers experiencing a 3-to-4-fold yield, less than expected. CDC director Thomas Frieden MD,MPH emphasized at a press conference that the agency, despite the shortage of vaccine, will not be switching H1N1 vaccine production techniques from the traditional "antiquated" chicken egg approach, to a more modern - and touted as a faster means of production - "cell culture" method. His reasoning which makes sense to me was that the H1N1 pandemic has a level of severity similar to the seasonal flu, even though the age-specific risk categories are strikingly different. Therefore while the publication of Vical Inc's results is indeed exciting, the US Food and Drug Admisnitration (FDA) is yet to approve the addition of adjuvant and subsequent modification of vaccine in order to amplify immune response. It is also important to note that these were preclinical data of studies conducted in mice.
(1) Hartikka Jet al. Vaxfectin(R), a cationic lipid-based adjuvant for protein-based influenza vaccines. Vaccine 2009;27:6399-6403
(2) Shlapobersky M et al. Vaxfectin(R)-adjuvanted seasonal influenza protein vaccine: Correlation of systemic and local immunological markers with formulation parameters. Vaccine 2009; 27:6404-6410
(3) Lowes, R. CDC defends reliance on "antiquated" H1N1 vaccine production despite shortages. http://www.medscape.com/viewarticle/711245
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That is fascinating. I wonder whether Vaxfectin is closely related to the squalene-derived adjuvant that has been licensed overseas for at least 10 years. And why the FDA seems to be so slow in approving adjuvants. Does anyone think it might have to do with the thimerosal scare of a few years ago, and no one at FDA wants to deal with a new storm of crazies?
ReplyDeleteI don't see how the FDA can dismiss the use Vaxfectin so quickly in their production of H1N1 vaccines. I recently read how certain people have no opportunity to get the vaccine due to their allergies to egg.
ReplyDeletehttp://www.cbc.ca/health/story/2009/10/28/ottawa-h1n1-egg-allergies-vaccine.html
I understand that population at greatest risk for H1N1 and allergic to eggs is probably very small, but none the less every person left untreated is one more person able to contract and spread the disease. A second option would prove very useful in reaching the greatest amount of people possible. There will never be a one-size fit all vaccine and we should carry a second option to provide the greatest amount of immunization if we hope to gain the greatest amount of "control".