FluGen’s investigational intranasal M2SR flu vaccine, in combination with Sanofi’s Fluzone High Dose, demonstrates superior protection and antibody response in adults aged 65-85.
RT’s Three Key Takeaways:
- Enhanced Immunological Response: The study demonstrated that co-administering FluGen’s intranasal M2SR vaccine with the high-dose flu shot significantly increased mucosal and serum antibodies against both matched and drifted strains of the influenza virus in older adults compared to the high-dose flu shot alone.
- Superior Protection for Seniors: Older adults aged 65-85, a population highly vulnerable to flu-related mortality, showed superior protection and improved immune responses when given the combination of intranasal and high-dose flu vaccines.
- Potential Pandemic Defense: The combined approach of intranasal and high-dose vaccines could offer a robust defense against mutating influenza strains, providing not only enhanced protection against seasonal flu but also a powerful tool in the event of a future influenza pandemic, according to researchers.
FluGen’s intranasal M2SR flu vaccine, when co-administered with the high-dose flu shot, has shown superior results in older adults ages 65-85 years compared to the flu shot alone, according to a new study published in the Lancet Infectious Diseases.
The study evaluated the safety, tolerability, and immunological response to FluGen’s investigational supra-seasonal, live, single-replication, intranasal influenza vaccine when administered with Sanofi’s Fluzone High Dose inactivated influenza vaccine (IIV).
There is a demonstrated unmet need for improved flu vaccine options, as current injectable vaccines primarily generate hemagglutinin antibodies and have shown only modest efficacy in most flu seasons. Funded by the US Department of Defense, this study evaluated M2SR and Fluzone High Dose alone, and dosed concomitantly, in healthy adults 65-85 years of age, a population considered highly vulnerable to mortality from flu.
“Influenza continues to be a major cause of seasonal respiratory epidemics with significant morbidity and mortality, especially in older adults. Current vaccines fall short in three main areas—they don’t last long enough, they don’t protect against viruses that mutate, and they don’t block the initial infection in the upper respiratory tract,” says Robert Belshe, MD, founder of Saint Louis University’s Center for Vaccine Development and recipient of the 2023 American College of Physicians James D. Bruce Memorial Award for Distinguished Contributions in Preventive Medicine, in a release. “The results from this study represent a potential solution that might save millions of older adults from getting sick or worse.”
Advantages of Intranasal Vaccines
Intranasal vaccines are known to provide a wall of defense at the site of infection to help prevent influenza viruses from entering the nasal mucosa. Intranasal M2SR has shown the ability to elicit mucosal antibodies and also protect against drifted strains while being durable.
Standard flu shots on the other hand, generate antibodies in the blood to help fight off the virus after it has already entered the body. Combining the benefits of both nasally delivered vaccines and the standard shot provide the best of both worlds, according to researchers.
The study demonstrated M2SR’s ability to statistically significantly raise mucosal antibodies in the nasal passages, serum antibodies against matched and drifted strains of the influenza virus, and cellular immune responses in subjects when compared to Fluzone High Dose and placebo.
Prior Study
In a prior phase 2 drifted H3N2 challenge trial, M2SR demonstrated efficacy against infection and illness across seven years of flu virus drift. Previous studies have also demonstrated that while currently licensed influenza vaccines administered by intramuscular injection generate tremendous antibody responses, only intranasal M2SR stimulates mucosal and cellular immunity as well as serum antibodies.
“The idea of delivering two vaccines in one sitting has become widely accepted,” says Paul Radspinner, president and chief executive officer of clinical-stage vaccine company FluGen, in a release. “Imagine being at your local pharmacy for your annual flu shot and also receiving a quick nasal spray that would greatly enhance your chances not only of becoming seriously ill but of being infected at all. This combination solution could have a tremendous impact on the health of older adults.”
Possible Pandemic Protection
Radspinner went on to discuss the possible impact on influenza pandemic protection. “If H5N1 or any other mutating influenza strain were to begin infecting millions of people as SARS-CoV-2 did, imagine the benefits of combining an intranasal vaccine, which could stop most infections from occurring, with a strong antibody-based vaccine shot. The impact on human health could be unequalled in our history,” he says in a release.
The randomized, double-blind, placebo-controlled phase 1b study, entitled FluGen H3N2 v006 was designed to evaluate a monovalent Cambodia 2020 H3N2 M2SR influenza A vaccine in a healthy, older adult population. The study enrolled over 300 subjects in four cohorts receiving either M2SR alone, high dose IIV alone, both vaccines concomitantly, or placebo. The primary endpoint was to assess the safety and tolerability of a single dose of monovalent M2SR influenza vaccine delivered intranasally alone or concomitantly with high dose IIV delivered intramuscularly to healthy subjects 65 to 85 years of age.
Secondary endpoints included evaluation of serum and mucosal antibody responses to matched and drifted strains of influenza virus following monovalent M2SR influenza vaccine delivered intranasally alone or concomitantly with high dose IIV delivered intramuscularly. Exploratory endpoints included evaluation of additional immune parameters such as T-cell responses.
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