1924. Outpatient Treatment With the SARS-CoV-2–Neutralizing Antibody Combination AZD7442 (Tixagevimab/Cilgavimab) for Preventing COVID-19 Hospitalizations in the Phase 3 TACKLE Trial

Abstract Background Outpatient treatment with SARS-CoV-2–neutralizing antibody combination AZD7442 (tixagevimab/cilgavimab) in adults mild to moderate COVID-19 significantly reduced progression severe disease or death through Day 29 and was well-tolerated the Phase 3 TACKLE study primary analysis (NCT04723394). administered earlier course leads more favorable outcomes has potential prevent hospitalizations reduce hospital burden. We report key secondary efficacy results longer-term safety data from over 6 months. Methods In TACKLE, non-hospitalized were randomized 1:1 dosed ≤7 days symptom onset a single 600-mg dose (2 consecutive intramuscular injections, 300 mg of each antibody; n=452) placebo (n=451). The endpoint any cause hospitalization for complications sequelae 169, analyzed using Cochran-Mantel-Haenszel test stratified by time risk progression. Results Death sequalae occurred 20 (5.0%) versus 40 (9.8%) participants receiving placebo, respectively, translating relative reduction (RRR) 49.1% (95% confidence interval [CI] 14.5–69.7) (P=0.009). A sensitivity excluding who unblinded prior 169 consideration vaccination yielded similar RRR 50.7% CI 17.5–70.5; P=0.006). For baseline seronegative participants, an 58.6% 27.6–76.4; P=0.001) observed. median (range) follow-up 170 (1–330) (1–326) placebo. Adverse events 38.5% 43.5% mostly moderate. Conclusion demonstrated statistically significant protection against months, well-tolerated. These provide further support outpatient setting, Disclosures F.D. Richard Hobbs, FMedSci, AstraZeneca: Grant/Research Support|AstraZeneca: Principal investigator|NIHR Applied Research Collaboration, Oxford Thames Valley: Director|Oxford BRC NIHR MedTech: Investigator|UKRI NIHR: Support Hugh Montgomery, MD, Advisor/Consultant|Millfield Medical Ltd: Advisor/Consultant|UK National Institute Health Research's Comprehensive Biomedical Centre at University College London Hospitals: Francisco Padilla, Amgen: Support|Amgen: Personal fees|AstraZeneca: fees|Boehringer Ingelheim: Support|Boehringer fees|Ferrer: Support|Ferrer: fees|Kowa: Support|Kowa: fees|Medix: Support|Medix: fees|Merck Sharp Dohme: Support|Merck fees|Novartis: Support|Novartis: fees|Pfizer: Support|Pfizer: fees|Sanofi: Support|Sanofi: fees|Servier: Support|Servier: fees|Silanes: Support|Silanes: fees Kenneth Kim, Adagio: Funding|Eli Lilly: Funding|Merck: Funding|Pfizer: Funding|Regeneron: Speaker|Regeneron: Funding Jesus Abraham Simón Campos, Board Member|AstraZeneca: Speaker|Eli Member|Pfizer: Member|Roche: Speaker Douglas Arbetter, MPH, Employee|AstraZeneca: Stocks/Bonds Kelly W. PharmD, Venkatesh P. Reddy, PhD, Seth Seegobin, Katie Streicher, Rolando M. Viani, Gavin CKW Koh, Mark T. Esser, Stocks/Bonds.