Clinical impact of tocilizumab therapy in SARS-CoV-2 respiratory infections in ICU and non-ICU patients

ABSTRACT

Background: Tocilizumab (TCZ) is a monoclonal antibody against the interleuikin- 6 receptor which is potentially beneficial in COVID-19 induced cytokine release syndrome (CRS). However, there are limited studies showing anti-inflammatory effect and clinical benefit of TCZ in COVID-19 patients. This retrospective study examines treatment responses of criteria based TCZ therapy for SARS-CoV-2 respiratory infection for ICU vs. non-ICU patients. Methods: We established institutional criteria to identify patients at risk of CRS from COVID-19. Patients were included if they received at least 1 dose of TCZ and were admitted for at least 72 hours. Primary endpoint was to assess clinical improvement (CI) at the end of admission. CI was defined by extubation, downgrade from ICU, discharged or improvement in Clinical Ordinal Scale by 2. Secondary endpoint of the study was to assess inpatient mortality (IM) and risk factors associated with IM. Subgroup analysis included impact of early (< 96 hours) vs late (≥ 96 hours) TCZ therapy on IM. Results: Between March 25 to May 6, 2020, 170 patients met criteria and received TCZ. There were 83 non-ICU patients and 87 in the ICU. Forty five patients needed invasive mechanical ventilation (IMV). ICU patients tended to be obese, receive 2 doses of TCZ and have longer length of stay. Overall CI was seen in 71% of patients. CI was higher in non-ICU vs ICU patients (85.5% vs 57.5%, P=0.002). Overall IM was 18.8%;however, IM was lower in non-ICU vs ICU patients (8.4% vs 28.7%, P=0.0014). IM was higher in patients on IMV vs. non-IMV (30% vs 15.4%, P=0.03). Risk factors of ICU admission, BMI ≥ 30 kg/m2 and AKI were associated with higher risk of IM. Many IM patients were made comfort care. No differences were observed in early vs late TCZ therapy on inpatient mortality, but there was a trend toward lower mortality with early TCZ. COS Review of Tocilizumab Patients Conclusion: TCZ is an effective treatment option in patients with SARS-CoV-2 patients at risk of CRS. Patients receiving TCZ in non-ICU setting had a better response to treatment compared to ICU patients. Obesity and AKI were associated with higher risk of mortality, but there was no statistical difference in early vs late therapy. Further studies with control group and larger sample size are warranted.