Higher levels of IL-6 early after tocilizumab distinguish survivors from non-survivors in COVID-19 pneumonia: a possible indication for deeper targeting IL-6

Introduction: The most serious COVID-19 deriving from severe acute respiratory syndrome coronavirus 2 causes cytokine release storm and it is associated with worse outcomes. In COVID-19 patients, Interleukin (IL)-6 levels are significantly elevated. Blocking IL-6 preliminary resulted in the improvement of this hyperinflammatory state. It is unknown which patients could require higher doses of tocilizumab to get out of the cytokine storm. Materials and Methods: Twenty-four patients affected by COVID-19 pneumonia were included. All the patients underwent tocilizumab 8 mg/kg intravenously and were tested for serum IL-6 24-48 hours before and 12-48 hours after tocilizumab infusion. Comparisons between survivors and non-survivors were performed. Results: Eighteen patients were discharged, while six patients died, with no clinical or laboratory differences between the two groups at baseline. IL-6 was not different at baseline (p=0.41), while 24-48h post-tocilizumab IL-6 serum levels were significantly higher in non-survivors than in survivors [2398.5 (430.5-9372) pg/mL vs 290.5 (58.5-1305.5) pg/mL, p=0.022)]. Serum IL-6 post-tocilizumab showed a good predictive ability to discriminate survivors from non-survivors (AUC 0.815 95%CI 0.63-0.99, p=0.02). Conclusion: Repeated measurement of serum level of IL-6 early after tocilizumab may distinguish non-survivors from survivors and support the choice of deeper targeting IL-6 in COVID-19 pneumonia. This article is protected by copyright. All rights reserved.