Tocilizumab for treatment of patients with severe COVID–19: A retrospective cohort study

BACKGROUND: Tocilizumab was approved for chimeric antigen receptor T–cell therapy induced cytokine release syndrome and it may provide clinical benefit for selected COVID–19 patients. METHODS: In this retrospective cohort study, we analyzed hypoxic COVID–19 patients who were consecutively admitted between March 13, 2020 and April 19, 2020. Patients with lung infiltrates and elevated inflammatory markers received a single dose of tocilizumab if no contraindication was present. Systemic steroid, hydroxychloroquine, and azithromycin were concomitantly used for majority of the patients. FINDINGS: Of the 51 patients included for analysis, 28 (55%) received tocilizumab and 23 (45%) did not receive tocilizumab. Tocilizumab cohort required more invasive ventilation (68% vs. 22%) at baseline and during entire hospitalization (75% vs. 48%). The median time to clinical improvement in tocilizumab vs. no tocilizumab cohorts was 8 days (Interquartile range [IQR]: 6·25 – 9·75 days) vs. 13 days (IQR: 9·75 – 15·25 days) among patients who required mechanical ventilation at any time (Hazard ratio for clinical improvement: 1·83, 95% confidence interval [CI]: 0·57 – 5·84) and 6·5 days vs. 7 days among all patients (Hazard ratio for clinical improvement: 1·14, 95% CI: 0·55 – 2·38), respectively. The median duration of vasopressor support and invasive mechanical ventilation were 2 days (IQR: 1·75 – 4·25 days) vs. 5 days (IQR: 4 – 8 days), p = 0.039, and 7 days (IQR: 4 – 14 days) vs. 10 days (IQR: 5 – 15 days) in tocilizumab vs. no tocilizumab cohorts, p = 0.11, respectively. Similar rates of hospital–acquired infections occurred in both cohorts (18% in tocilizumab and 22% in no tocilizumab cohort). INTERPRETATION: In patients with severe COVID-19, tocilizumab was associated with significantly shorter duration of vasopressor support. Although not statistically significant, tocilizumab also resulted in shorter median time to clinical improvement and shorter duration of invasive ventilation. These findings require validation from ongoing clinical trials of Tocilizumab in COVID–19 patients.