General Information

Flucelvax/Quadrivalent is an inactivated cell-culture-derived vaccine for influenza A and B. Cell-culture manufacturing technology provides an alternative production method to traditional egg-based production, utilizing a well-characterized mammalian cell line rather than chicken eggs to grow virus strains.

Flucelvax is specifically indicated for the active immunization in adults aged 18 years and older for the prevention of influenza disease caused by influenza virus subtypes A and type B contained in the vaccine.

Flucelvax Quadrivalent is specifically indicated for active immunization for the prevention of influenza disease caused by two influenza virus subtypes A and two influenza virus subtypes B in patients 6 months of age and older.

Flucelvax is supplied as a solution for intramuscular injection. The recommended dose is a single 0.5 mL intramuscular injection preferably in the region of the deltoid muscle of the upper arm.

Clinical Trial Results

The FDA approval of Flucelvax was based on the following study results:

Efficacy against Culture-Confirmed Influenza
A multinational (US, Finland, and Poland), randomized, observer-blinded, placebo-controlled trial was performed to assess clinical efficacy and safety of Flucelvax during the 2007-2008 influenza season. A total of 11,404 adults aged 18 through 49 years were enrolled to receive Flucelvax, Agriflu or placebo. Efficacy was assessed by the prevention of culture-confirmed symptomatic influenza illness caused by viruses antigenically matched to those in the vaccine and prevention of influenza illness caused by all influenza viruses compared to placebo. Antigenically Matched Strains: Flucelvax: 7 subjects with influenza (0.19% attack rate); placebo: 44 subjects with influenza (1.14% attack rate); 83.8% efficacy rate for Flucelvax. All Culture-Confirmed Influenza: Flucelvax: 42 subjects with influenza (1.11% attack rate); placebo: 140 subjects with influenza (3.64% attack rate); 55% efficacy rate for Flucelvax.
Immunogenicity in Adults 18 through 64 Years of Age
Data evaluating immunogenicity in adults 18 through 64 years of age were derived from 3 clinical studies, including 1,353 subjects that received Flucelvax. Immune responses measured by hemagglutination inhibition (HI) antibody titers to each virus strain in the vaccine were evaluated in sera obtained 21 days after administration of Flucelvax. Flucelvax demonstrated comparable immunogenicity to Agriflu for all three strains post-vaccination.
Non-inferiority in Adults 18 through 64 Years of Age
Non-inferiority of Flucelvax to Agriflu was demonstrated for HI antibody responses to all three strains for both post-vaccination geometric mean titer (GMT) ratios and seroconversion rates (i.e. the lower limit of the two-sided 95% CI for the ratio of the GMTs (Flucelvax/ Agriflu was >0.67; and the lower limit of the two-sided 95% CI for the difference between the seroconversion rates was >-10%).

The FDA approval of Flucelvax Quadrivalent was based on the following:

Flucelvax Quadrivalent is an evolution of Flucelvax trivalent influenza vaccine. Because both vaccines are manufactured using the same process and have overlapping compositions, the clinical efficacy and safety data from clinical trials with Flucelvax is relevant to Flucelvax Quadrivalent.

In clinical studies of adults aged 18 to 49 years, Flucelvax was shown to be efficacious against influenza caused by vaccine-like strains (83.8%) and by all circulating influenza strains (69.5%). Its quadrivalent formulation was also shown to be immunogenic against the flu in adults aged 18 years and older (Study 1) and children aged 4 through 17 (Study 2). Flucelvax Quadrivalent produced stronger antibody responses to the influenza B virus strain, which was not contained in the trivalent comparator flu vaccine.