Sanofi Pasteur's High-Dose Flu Vaccine Shows Superior Clinical Benefit in Older Adults

Results of a large-scale, multi-center efficacy trial in people 65 years of age and older showed a superior clinical benefit of Fluzone High-Dose (Influenza Virus Vaccine) relative to the standard dose of Fluzone vaccine in preventing influenza, Sanofi Pasteur, the vaccines division of Sanofi, announced in a press release.

Further data analyses of secondary endpoints are ongoing, including an evaluation of the relative efficacy based on the match of the vaccine strains to circulating influenza virus strains. Sanofi Pasteur anticipates submitting the full clinical study report to the FDA for review by early 2014 and will seek a modification to the label for Fluzone High-Dose vaccine reflecting the superior efficacy data in adults 65 years of age and older.

In the study, Fluzone High-Dose vaccine was approximately 24% more effective in preventing influenza in adults 65 years of age and older than Fluzone vaccine. The results met the prespecified primary objective of the study, demonstrating statistically superior efficacy for Fluzone High-Dose vaccine. Additionally, the study results suggested consistent clinical benefit across the study years, influenza virus types, clinical illness definitions, and laboratory methods of influenza confirmation. This large, multi-year trial also reaffirmed the safety of Fluzone High-Dose vaccine as demonstrated in previous studies.

Research has shown that the immune system weakens as people age. Older adults are more susceptible to infections and less responsive to vaccination. When infected with the influenza virus, they are less able to mount an effective immune response to neutralize the attack. “Influenza vaccines have been shown to offer public health benefits in preventing influenza and its complications in all age groups; however, older adults still have the highest rates of influenza-related hospitalization and death despite having high immunization rates,” said John Shiver, senior vice-president, research and development, Sanofi Pasteur, in the press release. “This led Sanofi Pasteur to develop Fluzone High-Dose vaccine, which this trial has confirmed provides better protection against influenza compared to Fluzone vaccine in people 65 years of age and older.”

Fluzone High-Dose vaccine contains 60 mcg of hemagglutinin antigen per strain of influenza virus in the vaccine as compared to 15 mcg of influenza virus hemagglutinin antigen per strain of influenza virus in standard dose Fluzone vaccine. Fluzone High-Dose vaccine was licensed by the FDA under an accelerated approval process to address the medical need in older adults. As a requirement of the accelerated approval pathway, Sanofi Pasteur embarked on this large-scale, two-season, confirmatory efficacy trial, involving more than 30,000 participants 65 years of age and older, to evaluate the clinical benefit of Fluzone High-Dose vaccine compared to Fluzone vaccine in the prevention of influenza disease.