Spike protein binding assays and neutralization assays using viruses representing all known SARS-CoV-2 variants of concern (VOCs) have been completed with STI-9167, and this nAb was observed to bind with high affinity and provide highly potent neutralizing activity (Omicron IC50 = 25 ng/ml). Of noted significance, STI-9167 is unique when compared to tests of EUA-approved SARS-CoV-2 nAbs in that binding and neutralization properties are maintained against the emerging Omicron and Omicron (+R346K) variant, an increasingly prevalent Omicron lineage variant that encodes an additional R346K Spike protein mutation. Additionally, STI-9167 administered at a low dose (5mg/kg) by either the intranasal or intravenous routes provided strong protection against the clinical signs of infection by the Omicron variant in the K18-hAce2 transgenic mouse model of COVID-19, preventing weight loss and reducing virus titers in the lungs to undetectable levels.
“The generation and characterization of the STI-9167 nAb demonstrates the great collaboration between the scientists of Mount Sinai and Sorrento to address a global health crisis,” said Domenico Tortorella, PhD, Professor of Microbiology at Icahn Mount Sinai.
“We selected antibody STI-9167 from large sets of diverse anti-SARS-CoV-2 spike neutralizing antibodies that we developed in our labs. It demonstrated the most effective cross-neutralization against all known SARS-CoV-2 isolates and variants of concerns, including the recent Omicron and Omicron (+R346K) variants,” commented J. Andrew Duty, PhD, Assistant Professor of Microbiology and Director of the Center for Therapeutic Antibody Development at Icahn Mount Sinai.
“The currently EUA-approved nAbs have markedly reduced or absent binding and neutralization activities against omicron/omicron (+R346K) making them inadequate to support current clinical needs,” stated Mike A. Royal, MD, JD, MBA, Chief Medical Officer at Sorrento. “Alternative nAbs are sorely needed in the near term, particularly for the pediatric population which appears to be at higher risk for severe omicron infection and hospitalization. Our intranasal COVIDROPS formulation delivers our nAbs to the upper airways where Omicron is most likely to target and flourish, and as a non-invasive, easy to administer treatment, it is ideal for children. We have already begun to treat children with COVIDROPS (with STI-2099) in Mexico where the delta variant is still prevalent. Through Phase 2 studies in the US, United Kingdom and Mexico, we have seen a benign safety profile for intranasal delivery of our nAbs and expect a similar outcome with COVIDROP (with STI-9167).”
“We now have had experience with bringing multiple COVID-19 therapeutics into the clinic and advancing several into Phase 2 and/or pivotal development,” says Mark Brunswick, PhD, SVP and Head of Regulatory Affairs and Quality at Sorrento. “We are well situated to rapidly bring forth COVISHIELD through the IND stage and into the clinic and expect to file this important IND in the next month.”
Dr. Henry Ji, Chairman and CEO of Sorrento, commented, “The work by the teams at Sorrento and Mount Sinai has yielded a remarkable antibody with unique and valuable protective properties against Omicron and all other SARS-CoV-2 VOCs. Our COVISHIELD neutralizing antibody is the best-in-class and the most advanced candidate for combatting the prevalent Omicron and emerging Omicron (+R346K) VOCs. We are working diligently to position this antibody for use in COVID patients and are confident that our approach will provide an efficacious clinical solution not only in the near term but also as the pandemic continues to evolve.”
A preprint manuscript was submitted on January 19, 2022 and will be published shortly online at biorxiv.org.
The neutralizing antibody described was generated in the laboratories at Mount Sinai and exclusively licensed to Sorrento Therapeutics. Mount Sinai and Mount Sinai faculty members have a financial interest in Sorrento Therapeutics.