A prospective, randomised, double blind placebo-controlled trial to evaluate the efficacy and safety of tocilizumab in patients with severe COVID-19 pneumonia (TOC-COVID): A structured summary of a study protocol for a randomised controlled trial.

SARS-CoV2 infection leads to a concomitant pulmonary inflammation. This inflammation is supposed to be the main driver in the pathogenesis of lung failure (Acute Respiratory Distress Syndrome) in COVID-19. Objective of this study is to evaluate the efficacy and safety of a single dose treatment with Tocilizumab in patients with severe COVID-19. We hypothesize that Tocilizumab slows down the progression of SARS-CoV-2 induced pneumonia and inflammation. We expect an improvement in pulmonary function compared to placebo-treated patients. Desirable outcomes would be that tocilizumab reduces the number of days that patients are dependent on mechanical ventilation and reduces the invasiveness of breathing assistance. Furthermore, this treatment might result in fewer admissions to intensive care units. Next to these efficacy parameters, safety of a therapy with Tocilizumab in COVID-19 patients has to be monitored closely, since immunosuppression could lead to an increased rate of bacterial infections, which could negatively influence the patient's outcome. Multicentre, prospective, 2-arm randomised (ratio 1:1), double blind, placebo-controlled trial with parallel group design. Inclusion criteria 1.Proof of SARS-CoV2 (Symptoms and positive polymerase chain reaction (PCR))2.Severe respiratory failure: a.Ambient air SpO Intervention arm: Application of 8mg/kg body weight (BW) Tocilizumab i.v. once immediately after randomisation (12 mg/kg for patients with <30kg BW; total dose should not exceed 800 mg) AND conventional treatment. Control arm: Placebo (NaCl) i.v. once immediately after randomisation AND conventional treatment. Primary endpoint is the number of ventilator free days (d) (VFD) in the first 28 days after randomisation. Non-invasive ventilation (NIV), Invasive mechanical ventilation (IMV) and extracorporeal membrane oxygenation (ECMO) are defined as ventilator days. VFD's are counted as zero if the patient dies within the first 28 days. The randomisation code will be generated by the CTU (Clinical Trials Unit, ZKS Freiburg) using the following procedure to ensure that treatment assignment is unbiased and concealed from patients and investigator staff. Randomisation will be stratified by centre and will be performed in blocks of variable length in a ratio of 1:1 within each centre. The block lengths will be documented separately and will not be disclosed to the investigators. The randomisation code will be produced by validated programs based on the Statistical Analysis System (SAS). Participants, caregivers, and the study team assessing the outcomes are blinded to group assignment. 100 participants will be randomised to each group (thus 200 participants in total). Protocol Version: V 1.2, 16.04.2020. Recruitment began 27th April 2020 and is anticipated to be completed by December 2020. The trial was registered before trial start in trial registries (EudraCT: No. 2020-001408-41, registered 21st April 2020, and DRKS: No. DRKS00021238, registered 22nd April 2020). The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.