Tocilizumab Treatment in Critically Ill Patients with COVID-19: A Retrospective Observational Study

Huang, Edmund; Isonaka, Sharon; Yang, Haoshu; Salce, Erin; Rosales, Elisa; Jordan, Stanley C.

Objective Elevated levels of pro-inflammatory cytokines are observed in severe COVID-19 infections and cytokine storm is associated with disease severity. Tocilizumab, an interleukin-6 receptor antagonist, is used to treat chimeric antigen receptor T cell-induced cytokine release syndrome and may attenuate the dysregulated immune response in COVID-19. We compared outcomes among tocilizumab-treated and untreated critically ill COVID-19 patients. Design, Setting, and Participants This was a retrospective observational study conducted at a tertiary referral center investigating all patients admitted to the intensive care unit for COVID-19 who had a disposition from the hospital because of death or hospital discharge between March 1, 2020 and May 18, 2020 (n=96). The percentages of death and secondary infections were compared between patients treated with tocilizumab (n=55) and those who were not (n=41). Measurements and Main Results More tocilizumab-treated patients required mechanical ventilation (44/55, 80%) compared to non-treated patients (15/41, 37%; p<0.001). Of 55 patients treated with tocilizumab, 32 (58%) were on mechanical ventilation at the time of administration and 12 (22%) progressed to mechanical ventilation after treatment. Thirty of 44 (68%) treated ventilated patients were intubated within one day of tocilizumab. Fewer deaths were observed among tocilizumab-treated patients, both in the overall population (15% vs. 37%; p=0.02) and among the subgroup of patients requiring mechanical ventilation (14% vs. 60%; p=0.001). Secondary infections were not different between the two groups (tocilizumab: 31%, non-tocilizumab: 17%; p=0.16) and were predominantly related to invasive devices, such as urinary and central venous catheters. Conclusions Tocilizumab treatment was associated with fewer deaths compared to non-treatment despite predominantly being used in patients with more advanced respiratory disease.