Horby RECOVERY 2021.

Study characteristics
Methods	RCT Blinding: unblinded Date of study: from 14 April 2020‐to 24 January 2021 Location: multicentre (131 centres) / UK Follow‐up duration (days): 28
Participants	Population: patients with suspected or confirmed COVID‐19 (moderate‐critical) admitted to 131 centres in the UK Randomised: 4116 participants (n1= 2022 / n2 = 2094) Characteristics of participants Mean age: 63.6 years 2772 males Admitted to ICU: n = NR Severity: mild: n = 9 / moderate: n = 1868 / severe: n = 1686 / critical = 562 Patients on oxygen without intubation: n = 3554 (86%); intubated: n = 562 (14%) C‐reactive protein (median): 143 to 144 mg/L Inclusion criteria Hospitalised adults patients (including pregnant women) with clinically suspected or laboratory‐confirmed SARS‐CoV‐2 infection Hypoxia (oxygen saturation < 92% on air or requiring oxygen therapy); evidence of systemic inflammation (C reactive protein (CRP) ≥ 75 mg/L) No medical history that might, in the opinion of the attending clinician, put patients at substantial risk if they were to participate in the trial Exclusion criteria A specific contra‐indication to 1 of the active drug treatment arms or that the patient should definitely be receiving one of the active drug treatment arms then that arm will not be available for randomization for that patient Patients with known hypersensitivity to tocilizumab, evidence of active tuberculosis infection or clear evidence of active bacterial, fungal, viral, or other infection (besides COVID‐19) were not eligible for randomization to tocilizumab Dropouts and withdrawals : 0% dropout, withdrawal due to AEs: NR
Interventions	Intervention: tocilizumab (800 mg if weight > 90 kg; 600 mg if weight > 65 and ≤ 90 kg; 400 mg if weight > 40 and ≤ 65 kg; 8 mg/kg if weight ≤ 40 kg); a 2nd infusion could be administered 12 to 24 hours after the 1st) Control: standard care Co‐interventions Steroid use at baseline or any time during the study Tocilizumab: 1664 (82%) Standard care: 1721 (82%)
Outcomes	Primary outcome of the trial 28‐day mortality Note: the definition of clinical improvement extracted is discharged alive from hospital within 28 days.
Notes	Funding: public/non profit (UK research and Innovation/National Institute for Health Research (NIHR); NIHR Oxford Biomedical Research Centre, Wellcome; Bill and Melinda Gates Foundation; Department for International Development; Health Data Research UK; Medical Research Council Population Health Research Unit; NIHR Clinical Trials Unit Support Funding; Abbvie (lopinavir‐ritonavir); Roche Products Ltd (tocilizumab); Regeneron (REGEN‐480 COV2)) Conflict of interest: yes, declared. The authors have no conflict of interest or financial relationships relevant to the submitted work to disclose Protocol: yes. In English Statistical plan: yes Data‐sharing stated: yes, within 3 months of publication Data accessibility: ndph.ox.ac.uk/data-access Overall comment: in addition to the pre‐print article, the study registry and protocol were used in data extraction and 'Rrisk of bias' assessment. This article is a preliminary report on the tocilizumab arm of the ongoing RECOVERY platform study after 28 days with the main analysis planned at 6 months post‐randomisation. As a result, the target sample size specified in the registry was not achieved. There is no change from the trial registration in the intervention and control treatments.