Dosing and Administration Strategies of Tocilizumab in Patients With COVID-19: A Retrospective Cohort Analysis

Background: Tocilizumab may reduce the risk of death, length of stay, and time of mechanical ventilation in patients hospitalized with COVID-19. Limited data are available evaluating low-dose subcutaneous administration of tocilizumab in this setting. Objective: To compare outcomes of 2 tocilizumab dosing and administration strategies in patients hospitalized with COVID-19. Methods: A retrospective, observational cohort study was conducted to compare clinical outcomes in patients hospitalized with COVID-19 receiving tocilizumab 400 mg intravenously (400 mg IV) or 162 mg subcutaneously (162 mg SC). Hospitalized patients receiving a single dose of tocilizumab were eligible for inclusion and grouped by dosing and administration strategy. The primary endpoint was ventilator-free days at day 28. Secondary endpoints included length of stay (LOS), intensive care unit (ICU) LOS, mechanical ventilation required after dose, 28-day readmission, 28-day mortality, and change in inflammatory markers. Results: A total of 303 patients were included, with 147 who received tocilizumab 400 mg IV and 156 who received 162 mg SC. There was no significant difference in average ventilator-free days at day 28 in patients receiving 400 mg IV compared with 162 mg SC (26.4 & PLUSMN; 5.3 vs 25.6 & PLUSMN; 6.8 days, respectively; P = 0.812). There was also no difference in LOS (10.4 & PLUSMN; 12.6 vs 10.5 & PLUSMN; 14.0 days; P = 0.637), ICU LOS (3.9 & PLUSMN; 9.0 vs 3.5 & PLUSMN; 8.3 days; P = 0.679), mechanical ventilation after dose (15.6% vs 19.2%; P = 0.412), 28-day readmission (6.1% vs 9.6%; P = 0.268), or 28-day mortality (23.1% vs 25.6%; P = 0.611). Finally, there was no difference regarding change in inflammatory markers at 48 hours (P > 0.05 for all interactions). Conclusion and Relevance: In this retrospective study involving hospitalized patients with COVID-19, there was no difference between tocilizumab 162 mg SC and 400 mg IV in terms of efficacy. The 162 mg SC dose may be a reasonable alternative to traditional doses.