Efficacy and safety of tocilizumab in severe COVID-19 patients: a single-centre retrospective cohort study

Background: Tocilizumab (TCZ), a humanized monoclonal antibody targeting the interleukin-6 (IL-6) receptor, has been proposed for the treatment of COVID-19 patients; however, limited data are available on the safety and efficacy. Methods: We performed a retrospective study on severe COVID-19 patients with hyper-inflammatory features admitted outside intensive care units (ICUs). Patients treated with intravenous TCZ in addition to standard of care were compared to patients treated with standard of care alone. Safety and efficacy were assessed over a 28-day follow-up. Results: 65 patients were included. Among them, 32 were treated with TCZ. At baseline, all patients were on high-flow supplemental oxygen and most (78% of TCZ patients and 61% of standard treatment patients) were on non-invasive ventilation. During the 28-day follow-up, 69% of TCZ patients experienced a clinical improvement compared to 61% of standard treatment patients (p = 0.61). Mortality was 15% in the tocilizumab group and 33% in standard treatment group (p = 0.15). In TCZ group, at multivariate analysis, older age was a predictor of death, whereas higher baseline PaO2:FiO2 was a predictor of clinical improvement at day 28. The rate of infection and pulmonary thrombosis was similar between the two groups. Conclusions: At day 28, clinical improvement and mortality were not statistically different between tocilizumab and standard treatment patients in our cohort. Bacterial or fungal infections were recorded in 13% of tocilizumab patients and in 12% of standard treatment patients. Confirmation of efficacy and safety will require ongoing controlled trials.