SAB Biotherapeutics, a clinical-stage biopharmaceutical company with a novel immunotherapy platform that produces specifically targeted, high-potency, fully-human polyclonal antibodies without the need for human donors, announced data demonstrating that SAB-185, the company’s therapeutic candidate for the treatment of COVID-19 infections, retains neutralization activity against the Omicron SARS-CoV-2 variant in an in vitro pseudovirus model. The data were generated by scientists at the US Food and Drug Administration (FDA) Center for Biologics Evaluation and Research (CBER).
“These in vitro data demonstrate that SAB-185 retains neutralization activity against the Omicron variant as has been consistently shown with previous SARS-CoV-2 variants of concern,” said Eddie J. Sullivan, PhD, Co-founder, President and CEO of SAB Biotherapeutics. “These encouraging data come at a critical time as COVID continues to assert its resilience in the human population around the globe. It also provides further evidence of the potential therapeutic importance of our polyclonal antibody approach to a highly mutating virus such as SARS-CoV-2.”
In the study, FDA researchers evaluated SAB-185 using a lentiviral-based pseudovirus assay conducted in a BSL2 environment that incorporates a stable 293T cell line expressing human angiotensin converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2). The results indicate that SAB-185 retains a potent ability to neutralize recombinant S protein lentiviral pseudovirus that mimics the SARS-CoV-2 Omicron (B.1.1.529) variant. Although SAB-185 retained potent neutralization of the Omicron variant, it did show a mild-moderate reduction in potency compared to the wild type. Additional analyses are ongoing, and the full data set is being prepared for bioRxiv, the online life sciences archive for COVID-19 SARS-CoV-2 preprints.
“As a targeted, high potency fully-human polyclonal antibody therapeutic candidate, SAB-185 is highly differentiated in the way by which it can address viral mutation potentially providing a more broadly active treatment option against COVID variants,” added Sullivan. “In addition to the retained neutralization activity of SAB-185 to the Omicron variant, it’s also important to note that there are multiple properties of polyclonal antibodies that can potentially provide therapeutic benefit to patients. For example, polyclonal antibodies can effectively block receptors used for viral entry by binding to multiple epitopes on the receptor binding domain, and they also may activate immune effector cells, further enhancing the individual’s immune response.”
SAB-185 is currently being assessed in a Phase 3 trial that has been enrolling patients since October. The antibodies within SAB-185 are directed against multiple epitopes within the full-length spike protein of the SARS-CoV-2 Wuhan strain. SAB-185 neutralizes the Munich, South African, Delta, Lambda, and other circulating variant strains in nonclinical studies. Preclinical data has also indicated that SAB-185 is significantly more potent than human-derived convalescent immunoglobulin G (IgG).
“Our versatile platform provides the capability to quickly add strains and adjust to new variants. We’re moving to optimize SAB-185 by adding activity directed to the Omicron variant,” added Christoph Bausch, PhD, Chief Scientific Officer of SAB Biotherapeutics. “SAB remains committed to monitoring the course of the disease and aiming to provide a polyclonal therapeutic response. We look forward to working with our US government collaborators and regulatory authorities to advance our COVID-19 program, with the goal of making SAB-185 available to patients, as quickly as possible once its clinical efficacy is confirmed.”