Polyclonal Antibody Treatment for Influenza Gets Fast Track Status

influenza virus particles
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SAB-176 is a fully-human broadly neutralizing immunoglobulin antibody therapeutic.

The Food and Drug Administration (FDA) has granted Fast Track designation to SAB-176 for the treatment of Type A and Type B influenza illness in high-risk patients, including those who have antiviral resistant strains.

SAB-176 is a novel, highly potent, neutralizing polyclonal immunoglobulin antibody designed to prevent or reduce severe outcomes of influenza infection in patients at high risk for severe complications, including immunocompromised individuals. 

The designation is supported by data from a proof-of-concept phase 2a trial (ClinicalTrials.gov Identifier: NCT04850898) that included healthy adult participants who were challenged with the H1N1 Influenza virus and then treated with either SAB-176 or placebo. Findings showed that treatment with SAB-176 led to a statistically significant reduction in viral load and was associated with broad cross protection. A statistically significant improvement in symptoms was observed by day 4.

“SAB-176 has the potential to be a game-changer in the fight against influenza,” said Alexandra Kropotova, MD, Chief Medical Officer of SAB Biotherapeutics. “Its multi-pronged mechanism of action, long half-life, and low risk of emergence of resistant strains could make it a superior therapeutic to achieve and sustain efficacy against this ever-evolving virus.”

The Company has started planning for a phase 2b trial that will evaluate SAB-176 in high-risk patients with Type A or Type B influenza illness, including those who have antiviral treatment resistant strains.


  1. SAB Biotherapeutics granted Fast Track designation from FDA for SAB-176 influenza immunotherapy with high cross-reactivity to multiple strains of influenza. News release. SAB Biotherapeutics. Accessed April 13, 2023. https://www.globenewswire.com/news-release/2023/04/13/2646194/0/en/SAB-Biotherapeutics-Granted-Fast-Track-Designation-from-FDA-for-SAB-176-Influenza-Immunotherapy-with-High-Cross-Reactivity-to-Multiple-Strains-of-Influenza.html.
  2. SAB Biotherapeutics. SAB Biotherapeutics Program Targeting Influenza: SAB-176. SAB Biotherapeutics. Accessed April 13, 2023. https://www.sab.bio/sab-176/.