REGEN-COV Antibody Combination and Outcomes in Outpatients with Covid-19
David M. Weinreich, Sumathi Sivapalasingam, Thomas Norton, Shazia Ali, Haitao Gao, Rafia Bhore, Jing Xiao, Andrea T. Hooper, Jennifer D. Hamilton, Bret J. Musser, Diana Rofail, Mohamed Hussein, Joseph Im, Dominique Y. Atmodjo, Christina Perry, Cynthia Pan, Adnan Mahmood, Romana Hosain, John D. Davis, Kenneth C. Turner, Alina Baum, Christos A. Kyratsous, Yunji Kim, Amanda Cook, Wendy Kampman, Lilia Roque-Guerrero, Gerard Acloque, Hessam Aazami, Kevin Cannon, J. Abraham Simón-Campos, Joseph A. Bocchini, Bari Kowal, A. Thomas DiCioccio, Yuhwen Soo, Gregory P. Geba, Neil Stahl, Leah Lipsich, Ned Braunstein, Gary Herman, George D. Yancopoulos
Abstract
BACKGROUND: In the phase 1-2 portion of an adaptive trial, REGEN-COV, a combination of the monoclonal antibodies casirivimab and imdevimab, reduced the viral load and number of medical visits in patients with coronavirus disease 2019 (Covid-19). REGEN-COV has activity in vitro against current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern. METHODS: In the phase 3 portion of an adaptive trial, we randomly assigned outpatients with Covid-19 and risk factors for severe disease to receive various doses of intravenous REGEN-COV or placebo. Patients were followed through day 29. A prespecified hierarchical analysis was used to assess the end points of hospitalization or death and the time to resolution of symptoms. Safety was also evaluated. RESULTS: copies per milliliter (95% CI, -1.00 to -0.72) in the 2400-mg group. Serious adverse events occurred more frequently in the placebo group (4.0%) than in the 1200-mg group (1.1%) and the 2400-mg group (1.3%); infusion-related reactions of grade 2 or higher occurred in less than 0.3% of the patients in all groups. CONCLUSIONS: REGEN-COV reduced the risk of Covid-19-related hospitalization or death from any cause, and it resolved symptoms and reduced the SARS-CoV-2 viral load more rapidly than placebo. (Funded by Regeneron Pharmaceuticals and others; ClinicalTrials.gov number, NCT04425629.).