POS1200 IL-6 HIGHER LEVEL AFTER TOCILIZUMAB TREATMENT AS A PREDICTOR OF NOT-SURVIVAL IN COVID19 SEVERE PNEUMONIA: THE EXPERIENCE OF THE COVIBAS-STUDY

Background: Cytokine release storm is the most fearsome complication associated with worse outcomes in COVID-19 patients with severe acute respiratory failure. In COVID-19 patients, interleukin-6 (IL-6) levels are significantly elevated. Blocking IL-6 preliminarily resulted in the improvement of this hyperinflammatory state. Objectives: To define if the serum level of IL-6 early tested after tocilizumab treatment could be useful to distinguish non-survivors from survivors in patients with severe respiratory failure due to COVID-19 pneumonia. Methods: This prospective cohort study was conducted at two referral hospitals for management of COVID-19 in Basilicata region, Italy: San Carlo Hospital, Potenza and Madonna delle Grazie Hospital, Matera. All consecutive patients with COVID-19 confirmed by RT-PCR testing of a naso-oropharyngeal swab. The enrollement period was from the 23rd of February to the 15th of August. 37 patients between all 124 underwent tocilizumab 8 mg/kg intravenously at baseline and after 24h. All patients were tested for serum IL-6, 24 hours before and 72 hours after tocilizumab infusion. Comparisons between survivors (Sv) and nonsurvivors (NSv) were performed. Results: 21 patients were discharged, while 16 patients died. The main clinical or laboratory differences (p < 0.001) between the two groups at baseline were mean diseases duration before ward admission and serum troponine levels. IL-6 was not different at baseline (p = 0.01), while 72 hours post-tocilizumab IL-6 serum levels were significantly higher in non-survivors than in survivors [(Sv 21.1%)vs(NSv 64%) p < 0.001)]. Serum IL-6 post-tocilizumab could be considered a good predictor to discriminate Sv from NSv. At multivariate stepwise analysis including disease duration at admission, baseline serum troponine levels and IL-6 post TCZ) were independent predictors of not survival Conclusion: Our data confirm the results of Quartuccio et al. In fact the highest burden of inflammation may be revealed by IL-6 levels after tocilizumab. Therefore repeated measurement of the serum level of IL-6 early after tocilizumab could be useful to distinguish non-survivors from survivors and support the choice of deeper targeting IL-6 in COVID-19 pneumonia. References: [1]Mehta P, McAuley DF, Brown M, et al. COVID-19: consider cytokine storm syndromes and immunosuppression. Lancet. 2020; 395(10229): 1033- 1034. [2]Toniati P, Piva S, Cattalini M, et al. Tocilizumab for the treatment of severe COVID-19 pneumonia with hyperinflammatory syndrome and acute respiratory failure: a single center study of 100 patients in Brescia, Italy. Autoimmun Rev. 2020; 19:102568 [3]McGonagle D, Sharif K, O’Regan A, Bridgewood C. The role of cytokines including interleukin 6 in COVID19 induced pneumonia and macrophage activation syndrome-like disease. Autoimmun Rev. 2020; 19(6):102537. [4]Chakraborty C, Sharma AR, Bhattacharya M, Sharma G, Lee SS, Agoramoorthy G. COVID19: consider IL6 receptor antagonist for the therapy of cytokine storm syndrome in SARS CoV2 infected patients. J Med Virol 2020 [5]Quartuccio L, Sonaglia A, Pecori D,et al. 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. J Med Virol.2020;92:2852–2856 Disclosure of Interests: None declared