Risk of reactivation of hepatitis B virus (HBV) and tuberculosis (TB) and complications of hepatitis C virus (HCV) following Tocilizumab therapy: A systematic review to inform risk assessment in the COVID era
Tocilizumab (TCZ), an IL-6 receptor antagonist, is used in the treatment of COVID. However, this agent carries a 'black box' warning for infection complications, which may include reactivation of tuberculosis (TB) or hepatitis B virus (HBV), or worsening of hepatitis C virus (HCV). Due to the pace of clinical research during the COVID pandemic, prospective evaluation of these risks has not been possible. We undertook a systematic review, generating mean cumulative incidence estimates for reactivation of HBV and TB at 3.3% and 4.3%. We could not generate estimates for HCV. These data derive from heterogeneous studies pre-dating the COVID outbreak, with differing epidemiology and varied approaches to screening and prophylaxis. We underline the need for careful individual risk assessment prior to TCZ prescription, and present an algorithm for clinical stratification. There is an urgent need for ongoing collation of safety data as TCZ therapy is used in COVID.