Research Institute of Influenza

Results show FluGen's investigational intranasal M2SR vaccine addresses an important unmet need by generating serum and mucosal antibodies against highly drifted strains of the H3N2 influenza virus MADISON, Wis., Nov. 9, 2022 /PRNewswire/ -- FluGen, Inc., a clinical-stage vaccine company transforming vaccine efficacy in infectious respiratory diseases, today announced the publication of new data in the Journal of Infectious Diseases showing its investigational, high dose, intranasal H3N2 M2SR influenza vaccine candidate substantially enhanced mucosal and serum antibodies against drifted H3N2 influenza viruses. Results showed that M2SR was well-tolerated at all dose levels and may provide substantial protection against infection with highly drifted strains of H3N2 influenza. "Antigenic drift, or circulating influenza virus strains that do not match the current influenza vaccines, are a serious public health problem, and the H3N2 strain has been particularly difficult to protect against in recent years," said Yoshihiro Kawaoka, Head of the Influenza Research Institute of the University of Wisconsin-Madison, Professor of the Institute of Medical Science of the University of Tokyo, and an author of the study. "These data suggest that the intranasal M2SR vaccine evaluated in the study may provide significant advantages over existing injected influenza vaccines." The publication, entitled "Intranasal M2SR ((M2-deficient Single Replication) H3N2 Influenza Vaccine Provides Enhanced Mucosal and Serum Antibodies in Adults", detailed results of a Phase 1B, observer-blinded, dose-escalation study of sero-susceptible subjects ages 18-49 years, randomized to receive two doses (108-109 TCID50) of M2SR or placebo administered 28 days apart. The primary objective was to demonstrate safety of M2SR vaccines (ClinicalTrials.gov number NCT03999554). Specific data demonstrated that, against the Belgium2015 challenge strain, a ≥2-fold increase in MN antibodies were noted among 40% (95% CI 24.9-56.7) of subjects following a single 108 TCID50 M2SR dose and among 80.6% (95% CI 61.4-92.3) after 109 dose (P<0.001). A single 109 TCID50 dose of M2SR generated ≥4-fold HAI seroconversion against the vaccine strain in 71% (95% CI 52.0-85.8) of recipients, a proportion substantially greater than reported for the only currently licensed intranasal flu vaccine. M2SR encoding antigen from 2018-19 influenza vaccine elicited mucosal antibodies that recognized future H3N2 strains that circulated in 2021 and 2022. Cellular immune responses were also induced. These results build on previous clinical evidence which showed that an intranasal dose of FluGen's M2SR vaccine candidate protected against infection and illness from seven years of highly drifted strains of H3N2 in subjects who demonstrated a ≥2-fold increase in microneutralization (MN) antibodies to the challenge strain after vaccination. 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 humoral immunity. "For decades, science has struggled to address the burden of viral drift in combatting influenza, as, when the circulating strain drifts, a mismatch between the virus and current vaccine occurs, and efficacy worsens; this is particularly true with the H3N2 strain," said Paul Radspinner, President and Chief Executive Officer of FluGen. "Previous efforts to address this challenge, such as adding adjuvants or quadrupling doses, have failed to improve outcomes for either matched or drifted strains. Now, we see further clinical evidence that our intranasal M2SR influenza vaccine candidate generates strong immunological response against both matched and drifted strains and may potentially be the more effective vaccine option that can help improve how we manage influenza." About FluGen: FluGen, Inc. is a clinical-stage vaccine company transforming vaccine efficacy in respiratory diseases. The company's lead candidate is M2SR, a supra-seasonal, live, single-replication, intranasal flu vaccine. Unlike standard of care flu vaccines, M2SR stimulates mucosal, humoral, and cellular immunity. In an unprecedented challenge trial, M2SR demonstrated protection against infection and illness across seven years of virus drift; and M2SR induces a durable antibody response with potential to cover an entire flu season and beyond. M2SR also has shown activity as a vaccine vector for other respiratory vaccines and infectious diseases, including a COVID-19/flu combination. For more information about FluGen, Inc., please visit . About M2SR: The M2 Deleted Single Replication Live Virus Vaccine (M2SR) offers a potentially differentiating clinical value proposition. FluGen's flu vaccine candidate is developed differently from inactivated or "killed" vaccines, which are comprised of flu viruses grown in eggs, chopped up, and purified for injection. It stimulates mucosal, humoral, and cellular immunity, and offers unprecedented efficacy against infection and illness across seven years of virus drift and documented immune response for at least six months. SOURCE FluGen Inc