Study 1 evaluated the immunogenicity of Flublok Quadrivalent as compared to a U.S.-licensed quadrivalent inactivated influenza vaccine (Comparator) (Fluarix Quadrivalent, manufactured by GlaxoSmithKline) in a randomized, observer-blind, active-controlled, multicenter trial conducted during the 2014-2015 influenza season in healthy adults 18-49 years of age. A total of 1350 subjects were enrolled, randomized 3:1, and vaccinated with Flublok Quadrivalent (998 subjects) or Comparator (332 subjects). Subjects were predominantly female (65%), white (60%), black/African American (37%), and of non-Hispanic/Latino ethnicity (84%), with a mean age of 33.5 years. Of the total vaccinated population, 1292 subjects (969 Flublok Quadrivalent and 323 IIV4 recipients, respectively) were evaluable for immune responses (Immunogenicity Population).
Post-vaccination immunogenicity was evaluated on sera obtained 28 days after administration of a single dose of study vaccine. Hemagglutination inhibition (HI) geometric mean titers (GMTs) were determined for the two vaccine groups for each vaccine antigen. Immunogenicity was compared by calculating the difference in seroconversion rates (SCR) and the ratios of GMTs of Comparator to Flublok Quadrivalent. Seroconversion was defined as either a pre-vaccination HI titer of <1:10 and a postvaccination HI titer of ≥1:40, or a pre-vaccination HI titer of ≥1:10 and a minimum 4-fold rise in postvaccination HI titer, at Day 28.
Study 1 had eight co-primary endpoints: Day 28 HI seroconversion rates and GMTs for each of the four antigens contained in the study vaccines. GMTs were compared based on the upper bound of the two-sided 95% CI of the GMT ratio of Comparator to Flublok Quadrivalent. Success in meeting this endpoint was pre-defined as an upper bound (UB) of the two-sided 95% CI of GMTComparator / GMTFlublok Quadrivalent ≤1.5. Flublok Quadrivalent met the success criterion for GMTs for three of the four antigens but not for the B/Victoria lineage antigen (Table 5).
|Antigen||Post-vaccination GMT Flublok QuadrivalentN=969||Post-vaccination GMT ComparatorN=323||GMT Ratio Comparator/Flublok Quadrivalent[95% CI]|
|Abbreviations: CI, confidence interval; GMT, geometric mean titer.|
Success in meeting the seroconversion rate (SCR) endpoint was pre-defined as an upper bound (UB) of the two-sided 95% CI of SCR Comparator – SCR Flublok Quadrivalent ≤10%. Flublok Quadrivalent met the success criterion for SCRs for three of the four antigens but not for the B/Victoria lineage antigen (Table 6). Sub-population analyses of immunogenicity did not reveal significant differences between genders. Sub-analyses according to race and ethnicity were not informative because the sizes of the subsets were insufficient to reach meaningful conclusions. The HI response to the B/Victoria lineage antigen was low in both vaccine groups.
|Antigen||SCR (%, 95% CI)Flublok QuadrivalentN=969||SCR (%, 95% CI)ComparatorN=323||SCR Difference (%)Comparator — Flublok Quadrivalent[95% CI]|
|Abbreviations: CI, confidence interval; SCR, seroconversion rateSeroconversion was defined as a pre-vaccination HI titer <1:10 and a post-vaccination HI titer ≥1:40 or a pre-vaccination HI titer ≥1:10 and a minimum four-fold rise in post-vaccination HI antibody titer.|
|A/H1N1||66.7 (63.6, 69.6)||63.5 (58.0, 68.7)||-3.2 (-9.2, 2.8)|
|A/H3N2||72.1 (69.2, 74.9)||57.0 (51.4, 62.4)||-15.2 (-21.3, -9.1)|
|B/Yamagata||59.6 (56.5, 62.8)||60.4 (54.8, 65.7)||0.7 (-5.4, 6.9)|
|B/Victoria||40.6 (37.4, 43.7)||58.2 (52.6, 63.6)||17.6 (11.4, 23.9)|
Flublok Quadrivalent is supplied as a single-dose, 0.5 mL syringe in a 5 or 10 syringe carton:
|Presentation||Carton NDC Number||Components and NDC Number|
|Single-Dose Prefilled Syringe||49281-720-10||Ten 0.5 mL single-dose prefilled syringes [NDC 49281-720-88]|
- Store refrigerated between 2°C and 8°C (36°F and 46°F).
- Do not freeze. Discard if product has been frozen.
- Protect syringes from light.
- Do not use after expiration date shown on the label.
Inform the vaccine recipient of the potential benefits and risks of vaccination with Flublok Quadrivalent.
Inform the vaccine recipient that:
- Flublok Quadrivalent contains non-infectious proteins that cannot cause influenza.
- Flublok Quadrivalent stimulates the immune system to produce antibodies that help protect against the influenza viruses carrying the proteins contained in the vaccine, but does not prevent other respiratory infections.
Instruct the vaccine recipient to report any adverse events to their healthcare provider and/or to the Vaccine Adverse Event Reporting System (VAERS).
Provide the vaccine recipient with the Vaccine Information Statements which are required by the National Childhood Vaccine Injury Act of 1986 to be given prior to vaccination. These materials are available free of charge at the Centers for Disease Control (CDC) website (www.cdc.gov/vaccines).
Encourage women who receive Flublok or Flublok Quadrivalent while pregnant to notify Sanofi Pasteur Inc. by calling 1-800-822-2463.
Instruct the vaccine recipient that annual vaccination to prevent influenza is recommended.
Manufactured by Protein Sciences Corporation (Meriden, CT).
U.S. license No. 1795.
Distributed by Sanofi Pasteur Inc.
Flublok is a registered trademark of Protein Sciences Corporation.
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