Phase 1 safety and pharmacokinetics studies of BRII-196 and BRII-198, SARS-CoV-2 spike-targeting monoclonal antibodies

Abstract Background BRII-196 and BRII-198 are two anti-SARS-CoV-2 monoclonal neutralizing antibodies with modified Fc region that extends half-life and are being developed as cocktail therapy for the treatment of COVID-19. Safety, tolerability, pharmacokinetics, and immunogenicity of BRII-196 and BRII-198 were investigated in healthy adults. Methods Single ascending doses of BRII-196 and BRII-198 were evaluated in parallel in the first-in-human, placebo-controlled phase 1 studies. A total of 32 healthy adults were randomized and received a single intravenous infusion of 750, 1500, and 3000 mg of BRII-196 (n=12), BRII-198 (n=12), or placebo (n=8) and were followed for 180 days. Results All infusions were well tolerated at infusion rates between 0.5 mL/min to 4 mL/min with no dose-limiting adverse events, deaths, serious adverse events, or any systemic or local infusion reactions. Most treatment-emergent adverse events were isolated asymptomatic laboratory abnormalities of Grade 1-2 in severity. Each mAb displayed pharmacokinetics expected of Fc-engineered human IgG1 with mean terminal half-lives of approximately 46 days and 76 days, respectively, with no evidence of significant anti-drug antibody development. Conclusions BRII-196 and BRII-198 were well-tolerated. Clinical results support further development as therapeutic or prophylactic options for SARS-CoV-2 infection. Clinical Trials Registration NCT04479631 and NCT04479644