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 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.