Efficacy and safety of IL-6 inhibitors in patients with COVID-19 pneumonia: a systematic review and meta-analysis of multicentre, randomized trials

Purpose: COVID-19 is characterized by dysregulated immune response, respiratory failure and a relevant mortality rate among hospitalized patients. Interleukin-6 (IL-6) is involved in COVID-19-associated cytokine storm, and several trials investigated whether its inhibition could improve patients’ outcome. We performed a meta-analysis of randomized trials (RCT) to test this hypothesis. Materials and methods: Two independent investigators searched PubMed, Scopus, ClnicalTrials.gov and medRxiv up to September 1st, 2021. Inclusion criteria were: administration of tocilizumab or sarilumab; COVID-19 adult patients with pneumonia; and being a RCT. Primary outcome was mortality at the longest follow-up. Secondary outcomes included intubation rate and incidence of adverse events. Two independent investigators extracted data from eligible trials. Results: Of the 763 studies assessed, 15 RCTs were included (9,320 patients), all were multicentre, and the majority open-label vs standard treatment. IL-6 inhibitors were associated with reduced all-cause mortality at the longest follow-up (1315/5,380 [24.4%] in the IL-6 inhibitors group versus 1080/3,814 [28.3%] in the control group, RR = 0.90; 95% CI 0.84 to 0.96; p for effect = 0.003, I2 = 0%, with 13 studies included), with reduction in 28/30-day mortality and intubation rates, and with no increase in adverse events and secondary infections. Conclusion: IL-6 inhibitors reduced longest follow-up mortality and intubation in COVID-19 patients. Findings need to be confirmed in high-quality RCTs.