Introduction
Coronavirus disease 2019 (Covid-19) pneumonia may be associated with a dysregulated immune response and hyperinflammation, which can lead to or exacerbate acute respiratory distress syndrome and multiorgan failure. Higher levels of interleukin-6 have been positively correlated with cases of critical and severe Covid-19, whereas lower levels of interleukin-6 have been correlated with mild disease. Therefore, tocilizumab has been recommended by several treatment guidance or consensus as an optional therapy for Covid-19[1, 2], which was an unapproved indication of tocilizumab.
Tocilizumab was launched in China in 2013 which was licensed to treat rheumatoid arthritis (RA) and systemic juvenile idiopathic arthritis (sJIA). The main active ingredient of tocilizumab is recombinant humanized anti-interleukin-6 receptor(IL-6R) monoclonal antibody that can specifically bind the membrane-bound IL-6 receptor (mIL6R) and soluble IL-6 receptor (sIL6R), thereby inhibiting signal transduction. Recent research has revealed, IL-6R play a key role in pathogenesis of a variety of immune diseases like Takayasu arterits[3], Adult-onset Still’s disease[4], et al. As more and more clinical trials and relevant studies around off-label use of tocilizumab have been implemented, some reliable evidences indicated that the treatment effect of tocilizumab not only be restricted to RA and JIA. Although some indications are not approved in China currently, the off-label use of tocilizumab is quite common in hospital especially in Chinese tertiary care hospital. The purpose of this study is to summarize and organize the clinical use situation of tocilizumab in Peking Union Medical College Hospital.