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

Abstract

Introduction: The most serious COVID-19 deriving from severe acute respiratory syndrome coronavirus 2 causes a cytokine release storm and it is associated with worse outcomes. In COVID-19 patients, interleukin-6 (IL-6) levels are significantly elevated. Blocking IL-6 preliminarily 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 to 48 hours before and 12 to 48 hours after tocilizumab infusion. Comparisons between survivors and nonsurvivors 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 =.41), while 24 to 48 hours post-tocilizumab IL-6 serum levels were significantly higher in nonsurvivors than in survivors (2398.5 [430.5-9372] vs 290.5 [58.5-1305.5] pg/mL, P =.022). Serum IL-6 post-tocilizumab showed a good predictive ability to discriminate survivors from nonsurvivors (area under the curve, 0.815; 95% confidence interval, 0.63-0.99, P =.02). Conclusion: Repeated measurement of the serum level of IL-6 early after tocilizumab may distinguish nonsurvivors from survivors and support the choice of deeper targeting IL-6 in COVID-19 pneumonia.