Baxter's Cell Culture-Based Pandemic Flu Vaccine Receives EMEA Positive Opinion

Celvapan, the first cell culture-based H5N1 (avian flu) pandemic vaccine, has moved closer to approval in the European Union. On December 18, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMEA), issued a positive opinion, recommending market authorization for the vaccine, made by Baxter International, Inc. (Deerfield, IL).

The positive opinion precedes the licensure of the “mock-up” vaccine, which allows Celvapan to be used if the World Health Organization (WHO) officially declares a pandemic. The positive opinion was based on results from a comprehensive clinical development program, including a Phase 3 clinical trial that demonstrated vaccines for two different H5N1 virus strains were well tolerated and generated a functional immune response.

A “mock up” vaccine is identical to the future pandemic vaccine in composition and manufacturing; however, since the actual pandemic strain is not known, the vaccine contains another influenza strain not yet exposed to the general population. Once a pandemic is declared, licensure of the mock up allows for a fast track approval of the vaccine containing the actual pandemic strain.

Celvapan is made using Baxter’s proprietary Vero cell technology, which offers advantages against conventional egg-based vaccine technology. Baxter’s Vero cell manufacturing process uses the “native” virus that does not need to be modified to grow in chicken eggs, making the process faster than traditional vaccine manufacturing. The shorter time for vaccine production is critical in accelerating vaccine supply in response to an influenza pandemic.

Celvapan is produced in Bohumil, Czech Republic, at one of the largest cell culture vaccine production facilities in the world. Vero cell technology uses a well-established continuous mammalian cell line to produce the pandemic vaccine.

Baxter’s candidate avian flu vaccine is derived from the H5N1 strain A/Vietnam/1203/2004. Its antigen composition and structure are identical to the actual virus circulating in nature. This vaccine formulation alleviates the need to enhance the immune response by including adjuvants that may cause side effects. In the Phase 3 study, Celvapan induced an immune response that is similar to the body’s defense against a natural influenza virus infection.