LB14. Safety and Immunogenicity of High-Dose Quadrivalent Influenza Vaccine Administered by Intramuscular Route in Subjects Aged 65 Years and Older
Session: Oral Abstract Session: Late Breaker Oral Abstracts: Influenza and Vaccines
Saturday, October 6, 2018: 10:30 AM
Room: S 152-154
Background: Older adults (≥65 years of age) remain at increased risk of influenza because they do not respond to standard dose influenza vaccines as well as younger adults. A high dose, inactivated trivalent influenza vaccine, IIV3-HD, containing four times the antigen content (60 µg hemagglutinin per influenza strain) of standard-dose influenza vaccines has been available in the US since 2010. Two distinct B influenza lineages (Victoria and Yamagata) have co-circulated for over a decade, making it difficult to predict which will predominate the next season. IIV4-HD has been developed to address the frequent influenza B strain mismatches by incorporating a strain from each B lineage. This pivotal Phase III study evaluated the safety and immunogenicity of IIV4-HD as compared to two IIV3-HD vaccines.

Method: A randomized, modified double blind, multicenter study (NCT03282240) was conducted in 2670 healthy subjects in the United States, who were randomly assigned to receive IIV4-HD, a licensed IIV3-HD, or an IIV3-HD with the alternate B influenza strain. Using the hemagglutinin inhibition (HAI) assay at baseline and 28 days after vaccination, post-vaccination geometric mean titers and seroconversion rates were measured. Safety data were collected through six months post-vaccination.

Result: IIV4-HD was non-inferior to the licensed IIV3-HD and the investigational IIV3-HD (containing the alternate B strain) for all 4 influenza strains as assessed by HAI GMTs and seroconversion rates. Moreover, IIV4-HD induced a superior immune response (HAI GMTs and seroconversion rates) compared to the immune response induced by the IIV3-HD that does not contain the corresponding B strain. Reactogenicity profiles were comparable across all study groups. Most unsolicited adverse events were of Grade 1 or Grade 2 intensity. One serious adverse event considered related by the Investigator was reported in the IIV4-HD group.

Conclusion: Vaccination of adults 65 years of age and older with IIV4-HD was found to be non-inferior to two IIV3-HD vaccines with a similar safety profile. The addition of a second B lineage strain does not adversely affect the safety or immunogenicity profile of IIV4-HD compared with IIV3-HD.

Lee-Jah Chang, MD1, Ya Meng, PhD1, Helene Janosczyk, MA1, Victoria Landolfi, MSc, MBA1, H. Keipp Talbot, MD, MPH2 and the QHD00013 Study Team, (1)Sanofi Pasteur, Swiftwater, PA, (2)Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN

Disclosures:

L. J. Chang, Sanofi Pasteur: Employee , Salary .

Y. Meng, Sanofi Pasteur: Employee , Salary .

H. Janosczyk, Sanofi Pasteur: Employee , Salary .

V. Landolfi, Sanofi Pasteur: Employee , Salary .

H. K. Talbot, Sanofi Pasteur: Investigator , Research grant . Gilead: Investigator , Research grant . MedImmune: Investigator , Research grant . Vaxinnate: Safety Board , none . Seqirus: Safety Board , none .

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