ABSTRACT
We administered tocilizumab into 13 severe-to-critically ill patients with coronavirus disease 2019 (COVID-19) for compassionate use in combination with potential anti-viral agents in those who required an oxygen supply and showed increased laboratory inflammatory markers such as C-reactive protein (CRP) and ferritin. One injection of tocilizumab led to rapid improvements in clinical features, inflammatory findings, and oxygen supply in seven patients with severe COVID-19 and substantial amelioration in two patients who were critically ill, whereas four patients, who exhibited rapidly worsened respiratory function, required artificial ventilatory support even after tocilizumab treatment. Three of these four patients ultimately recovered from deterioration after methylprednisolone treatment. Administration of tocilizumab did not affect viral elimination nor IgG production specific for the virus. Compared with well-responding patients, rapidly-worsened patients showed a significantly higher ratio of ferritin vs. CRP. These findings suggest that tocilizumab has beneficial effects in severe-to-critically ill patients with COVID-19; however, in some cases, addition of methylprednisolone is required for disease rescue.