By Elizabeth Finkel
MELBOURNE, AUSTRALIA—A warning letter from the U.S. Food and Drug Administration (FDA) to Australian vaccine maker CSL Biotherapies has shaken confidence in the country’s biotech superstar. The 15 June letter accuses CSL of failing to adequately investigate why its Fluvax influenza vaccine last year caused a sharply elevated rate of febrile convulsions in some children under the age of five. “There was no analysis of all critical parameters and critical processing steps to try to determine differences in the 2010 lots associated with Adverse Event reports compared to lots from previous seasons” the letter states. The letter gave CSL 15 days to respond to its concerns or risk losing its license to sell Fluvax in the United States, where it is marketed under the name Afluria.
“We are taking the warning letter very seriously,” said Jeff Davies, executive vice president of CSL Biotherapies, in a prepared statement. “Our technical team is in the process of preparing more substantive detail about our corrective actions to meet the FDA’s requirements.”
CSL Biotherapies is one of Australia’s top biotech performers, with 2010 revenue of $4.8 billion; worldwide sales of Fluvax were $130 million, including $56 million in the United States. Following adverse reactions to the flu vaccine reported in 2010, FDA sent inspectors in June to CSL’s manufacturing plant in Melbourne. After a second visit last March, FDA issued its warning letter, which stated that CSL’s Quality Control Unit had failed to “fulfill its responsibility to assure the identity, strength, quality, and purity of your monovalent influenza bulks and final drug products.”
A recent study by Paul Armstrong at the Department of Health, Western Australia, and colleagues reported that the rate of febrile convulsions among young children was 3.3 per 1000 doses, 200 times that reported in a U.S. influenza vaccine safety study. The same study indicated that febrile convulsions were linked to CSL’s vaccine but not to equivalent vaccines such as Influvac and Vaxigrip.