Ongoing studies will fine-tune Celvapan dose level and dosing schedule.
The European Commission sanctioned Baxter’s Celvapan H1N1 pandemic flu vaccine, produced using its Vero cell technology. The company claims the vaccine is the first cell culture-based, nonadjuvanted pandemic flu vaccine to get EU clearance.
Baxter is currently carrying out clinical trials of Celvapan H1N1 and said that it will supplement the licensure postapproval with additional clinical program data. The company will also provide the EMEA with immunogenicity data from the first vaccination in adults within the next few days.
The current dosing schedule specified in the agency’s mock-up licensure for Celvapan using another virus strain involves two 7.5 microgram doses, given 21 days apart. Baxter said a trial in healthy adults will indicate whether a single dose may be enough for the Celvapan H1N1 vaccine. The trial will also determine whether a lower, 3.75 microgram dose is sufficient to induce the required immune response.
The EMEA implemented its mock-up licensure regulatory pathway for pandemic vaccines in 2004. The pathway allows companies to develop, evaluate, and register a pandemic vaccine candidate using an available influenza strain that has the potential to cause a pandemic. Once a flu pandemic occurs and the responsible strain is isolated, the mock-up licensure process allows for fast-track approval of the vaccine containing the actual pandemic strain.
Baxter was granted mock-up licensure for Celvapan using a different strain earlier this year. This vaccine was tested internationally through five completed clinical trials. The company received the causative pandemic H1N1 strain from the U.S. CDC in May and undertook preproduction testing and evaluation to assess the strain’s growth characteristics in the Vero cell culture technology.
Commercial production was then started in early June, and Baxter initiated its license application for the final Celvapan H1N1 vaccine in July. Bulk Celvapan H1N1 vaccine is now produced at Baxter’s facility in the Czech Republic and is subsequently sent to Austria for final formulation, fill, and finish.