Impact of early tocilizumab administration on the progression of respiratory failure in COVID-19 patients

The optimal interval for initiating tocilizumab therapy in patients with COVID-19 (COronaVIrus Disease 2019) has not been determined. The aim of the study was to evaluate the effectiveness of prescribing tocilizumab depending on the duration of persistent hyperthermia > 38 °С in patients with SARS-CoV-2 (Severe Acute Respiratory Syndrome-related CoronaVirus 2) associated pneumonia who received tocilizumab according to the Interim Guidelines of the Ministry of Health of the Russian Federation (version at the time of inclusion in the study). Methods. A retrospective cohort study was conducted in hospitalized patients (n = 163) with SARS-CoV-2-associated pneumonia from May 2020 to May 2021. Patients were retrospectively divided into 2 groups depending on the time of tocilizumab administration: ≤ 7 days (n = 61) or ≥ 8 days (n = 102) from the disease onset. Results. Patients who received tocilizumab in the first 7 days had the lower need for CPAP (Continuous Positive Airway Pressure) therapy on day 3 after tocilizumab therapy (HR (Hazard Ratio) – 0.129 (0.039 – 0.430); p = 0.001), a higher probability of a decrease in the volume of lung lesions on computed tomography > 25% a week after the use of tocilizumab (HR – 1.065 (1.036 – 1.093); p = 0.001), the lower probability of hemoglobin oxygen saturation below 92% on day 3 (HR – 0.807 (0.750 – 0.869); p = 0.001), and day 7 (HR – 0.825 (0.772 – 0.883); p = 0.001) after tocilizumab therapy. If CPAP therapy was required on day 3 after administration of tocilizumab, each day of delay in prescribing the drug increased the risk of an adverse outcome 18-fold (HR – 18.24 (5.328 – 62.438); p = 0.001). The duration of hospitalization was significantly lower in the early group than in the late group (10 (8.5 – 15) vs 13.5 (10 – 18) days, respectively; p = 0.02). The mortality was similar (5 (8.2%) vs 6 (5.9%) patients, respectively; p = 0.748). Conclusion. The administration of tocilizumab in the first seven days from the onset of the disease in patients with COVID-19 who developed systemic inflammation and lung damage may prevent the need for escalation of respiratory support and accelerate recovery compared with the later tocilizumab administration.