Tocilizumab: From Rheumatic Diseases to COVID-19

Tocilizumab is a humanised interleukin-6 receptor-inhibiting monoclonal antibody that is currently approved for the treatment of rheumatoid arthritis and other immune-related conditions. Recently, tocilizumab has been investigated as a possible treatment for severe coronavirus-induced disease 2019 (COVID-19). Despite the lack of direct antiviral effects, tocilizumab could reduce the immune-induced organ damage caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV2) infection. Until recently, most reports on tocilizumab for COVID-19 included a limited number of patients, preventing an overall evaluation of its efficacy and safety for this specific condition. Therefore, we reviewed the literature regarding the physiopathological rationale of tocilizumab for COVID-19 and its outcomes. We searched the MEDLINE database with the string "(SARS-CoV-2 OR coronavirus OR COVID-19 OR MERS- cov OR SARS-cov) AND (IL-6 OR interleukin 6 OR tocilizumab)". While the scientific rationale supporting tocilizumab for COVID-19 is solid, the evidence regarding the outcomes remains controversial. Available data and results from ongoing trials will provide useful information in the event of new COVID-19 outbreaks or future pandemics from different coronaviruses.