Clinical trials of a new type of seasonal influenza vaccine, manufactured in cell culture rather than chicken eggs, have got underway in the USA. The manufacturing approach could slash the time it takes to make batches of vaccine from months to weeks.

Sanofi Pasteur, the vaccines unit of France’s Sanofi-Aventis, said the trials would enrol around 100 volunteers and compare the new call-made vaccine with a control made using traditional egg-based technologies.

The US government is backing the study and has thrown its weight behind the development of alternative flu vaccine supplies in the wake of supply problems in the 2004/5 flu season caused by manufacturing problems at a plant operated by Chiron.

That plant was scheduled to supply nearly half the entire flu vaccine requirement of the USA and only a mild flu season and the efforts of other manufacturers to plug the gap prevented the shortages becoming a major problem.

The problems at the plant, now owned by Novartis, have largely been resolved. But with Sanofi itself reporting quality control issues at a plant making its Fluzone product, which makes up around 50% of the USA’s supply, the need for alternative production capacity becomes apparent.

Cell culture production is one way to improve the reliability of supply. Using chicken eggs to cultivate the vaccine leads to long production cycles and restricts capabilities to respond quickly to a crisis. In contrast, cell culture production enables flexible, faster start-up of manufacturing, and is independent of the availability of eggs, an important advantage in the event of an influenza epidemic or pandemic.

Sanofi said the clinical trials have been made possible by the first commercial-scale production of a cell culture-produced flu vaccine, a combined effort between Sanofi and biomanufacturing specialist Lonza using the PER.C6 cell line developed by Crucell.

The clinical study is the first step toward Sanofi Pasteur filing a Biologics License Application for a cell culture-based trivalent split inactivated seasonal influenza vaccine with the US Food and Drug Administration.