Vaccine Info

Redeeflu (M2SR) Influenza Vaccine

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Last reviewed
September 8, 2021

Redeeflu (M2SR) Influenza Description

Redeeflu (M2SR) is a nasal vaccine candidate utilizing a proprietary M2 deleted, single replication (M2SR) influenza virus. M2SR, a supra-seasonal, live, single-replication, intranasal flu vaccine. The M2 gene is essential for the influenza virus to spread in the patient, and the deletion of the M2 gene restricts the virus to a single replication cycle in the host.

The M2SR vaccine candidate contains vaccine viruses with a deletion in a portion of the M2 gene. M2SR viruses can infect cells, express the entire spectrum of influenza RNA and proteins, yet cannot produce any infectious virus particles. Thus, the M2SR vaccines do not shed infectious viruses and do not cause any pathological signs of infection. The M2SR viruses can be engineered to express the HA and neuraminidase antigens (NA) of any influenza virus and can be manufactured in cell lines that stably express the M2 protein.

The body recognizes M2SR as an influenza infection. It activates its robust immune response, but because the virus can replicate only once, it cannot spread to other cells and cause symptoms of real influenza infection.

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 the 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.

The RedeeFlu viruses can be engineered to express the HA and neuraminidase antigens (NA) of any influenza virus and can be manufactured in cell lines that stably express the M2 protein.

“Current vaccines are strain-specific, and in recent years they have had low efficacy against H3N2 influenza, especially when the vaccine is mismatched to circulating virus,” said Dr. Robert Belshe, Chair of the FluGen Clinical Advisory Board, on August 2, 2021. “The M2SR vaccine candidate is designed to induce a broad, multi-effector immune response, and this study demonstrated that subjects with vaccine-induced neutralizing antibodies were protected against infection and illness following challenge with an antigenically drifted virus. Inactivated vaccines have not had that broad protection. Thus, this is the first demonstration in adults of vaccine-induced protection against a highly drifted H3N2 challenge virus.”

FluGen raised $12 million in a Series A financing.  Venture Investors LLC, the Wisconsin Alumni Research Foundation, the State of Wisconsin Investment Board, and other new investors participated in this first institutional financing of the company, along with many of FluGen’s existing investors led by Knox LLC.  In addition, FluGen has secured over $40 million from the NIH and the Department of Defense. FluGen, Inc. is located at 597 Science Drive, Madison, WI 53711.

Redeeflu (M2SR) Influenza Indication

Redeeflu is indicated to prevent influenza in seniors. The company says 'currently approved influenza vaccines are moderately effective against three or four strains of influenza. However, recent evaluations conducted by a US government-supported network of large clinics (US Flu-VE Network) have demonstrated overall vaccine effectiveness (VE) of only 60% (95% CI, 53-66), even in years in which there was a good match between vaccine and circulating strains.'

Redeeflu (M2SR) Influenza Dosage

Redeeflu is administered intranasally.

Redeeflu (M2SR) Influenza News

August 2, 2021 - FluGen, Inc. announced the publication of results from its Phase 2a human challenge study of Bris2007 M2SR, the Company’s investigational, supra-seasonal, live, single-replication, intranasal influenza (flu) vaccine. Results published in the Journal of Infectious Diseases show that subjects with vaccine-induced neutralizing antibodies were protected against infection and illness following a challenge with an antigenically distinct virus. This is believed to be the first demonstration of vaccine-induced protection against a highly drifted H3N2 influenza virus in a human challenge study.

July 1, 2021 - FluGen, Inc. announced that it had been awarded funding from the United States Department of Defense to conduct a safety and immunogenicity study of M2SR, the Company's investigational, supra-seasonal, live, single-replication, intranasal influenza vaccine. This study will evaluate a monovalent H3N2 flu vaccine candidate compared to a licensed quadrivalent vaccine considered the current standard of care for adults aged 65 and above. 

June 4, 2021 - FluGen President & CEO Paul Radspinner speak at the Jefferies 2021 Virtual Healthcare Conference

May 25, 2021 - FluGen Initiates NIH-Funded Trial of M2SR Flu Vaccine; First Study in Adults Up to Age 85.

April 2, 2020 - An international collaboration of virologists at the University of Wisconsin–Madison and the vaccine companies FluGen and Bharat Biotech has begun developing and testing a unique vaccine against COVID-19 called CoroFlu.

October 18, 2017 - FluGen Awarded $14.4 million by the Department of Defense to Test Universal Flu Vaccine Against Mismatched Strains. Under the three-year award, FluGen will conduct two challenge studies with RedeeFlu.

July 27, 2016 - FluGen Inc. announced the initiation of the first Phase 1 clinical trial of its RedeeFlu™ universal influenza vaccine. The trial is a randomized, blinded, dose-ranging Phase 1 study of the H3N2 RedeeFlu™ influenza vaccine in 96 healthy adult subjects between 18 and 49 years of age. In addition to the trial’s primary goal of evaluating the vaccine's safety in this population, the study also will evaluate both antibody and T-cell responses induced by the vaccine.

Redeeflu (M2SR) Influenza Clinical Trials

Redeeflu influenza vaccine candidate continues to be tested in clinical trials.