Background: The role of remdesivir inThe primary outcome was in-hospital 24.8% and 28.2%, respectively (95% CI the treatment of patients in hospital mortality. Secondary outcomes 0.72 to 1.07). For patients not mechanwith COVID-19 remains ill defined in a included changes in clinical severity, ically ventilated at baseline, the need for global context. The World Health Organ-oxygen-and ventilator-free days (at mechanical ventilation was 8.0% in those ization Solidarity randomized controlled 28 d), incidence of new oxygen or assigned remdesivir, and 15.0% in those trial (RCT) evaluated remdesivir in mechanical ventilation use, duration of receiving standard of care (RR 0.53, 95% CI patients across many countries, with hospital stay, and adverse event rates. 0.38 to 0.75). Mean oxygen-free and Canada enrolling patients using anWe performed a priori subgroup analy-ventilator-free days at day 28 were 15.9 expanded data collection format in the ses according to duration of symptoms (± standard deviation [SD] 10.5) and 21.4 Canadian Treatments for COVID-19 before enrolment, age, sex and severity (± SD 11.3) in those receiving remdesivir (CATCO) trial. We report on the Canad-of symptoms on presentation. and 14.2 (± SD 11) and 19.5 (± SD 12.3) in ian findings, with additional demo-those receiving standard of care (p = 0.006 graphics, characteristics and clinical Results: Across 52 Canadian hospitals, and 0.007, respectively). There was no difoutcomes, to explore the potential for we randomized 1282 patients between ference in safety events of new dialysis, differential effects across different Aug. 14, 2020, and Apr. 1, 2021, to remde-change in creatinine, or new hepatic dyshealth care systems.sivir (n = 634) or standard of care (n = function between the 2 groups. 648). Of these, 15 withdrew consent or Methods: We performed an open-label, were still in hospital, for a total sample of Interpretation: Remdesivir, when compragmatic RCT in Canadian hospitals, in 1267 patients. Among patients assigned pared with standard of care, has a modest conjunction with the Solidarity trial. We to receive remdesivir, in-hospital mortal-but significant efect on outcomes imporrandomized patients to 10 days of rem-ity was 18.7%, compared with 22.6% in tant to patients and health systems, such desivir (200 mg intravenously [IV] on day the standard-of-care arm (relative risk as the need for mechanical ventilation. 0, followed by 100 mg IV daily), plus[RR] 0.83 (95% confidence interval [CI] Trial registration: ClinicalTrials.gov, no. standard care, or standard care alone. 0.67 to 1.03), and 60-day mortality was NCT04330690.