Use of Tocilizumab in COVID-19: A Systematic Review and Meta-Analysis of Current Evidence

Background and objectives A flare-up in coronavirus disease 2019 (COVID-19) cases threatens the health of people, and though there is no proven pharmacological treatment, many analytical studies have suggested that interleukin-6 (IL-6) levels are elevated in cases of severe COVID-19 and that the anti-IL-6 biologic agent tocilizumab may be beneficial. This is a critical review of studies aiming to assess the safety and efficacy of tocilizumab as compared to the standard regimen in patients with COVID-19. Materials and methods Online databases (PubMed and Cochrane) were searched until June 29, 2020, for original articles investigating the immunological response in COVID-19 and its treatment with tocilizumab. Data on multiple baseline characteristics and pre-specified endpoints were extracted and pooled using a random effect model. We used Review Manager version 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, 2014, Denmark) and Stata 11.0 (Stata Corporation LP, College Station, TX) for all analyses. Risk ratios (RR) and the weighted mean difference (WMD) with the corresponding 95% confidence interval (CI) were calculated. Results From a total of 1,246 identified articles, 13 studies were included after duplicate removal and narrowing based on title and abstract. Of the 13 included studies, seven case-control studies were shortlisted for meta-analysis (quantitative) and six-single arm studies were used in the discussion (qualitative). These studies had 766 patients (351 in the tocilizumab arm and 414 in the control arm). Their pooled analysis demonstrated that mortality was significantly lower in the tocilizumab group (RR=0.56 [0.34, 0.92]; p=0.02; I(2)=76%), as was the need for artificial invasive ventilation (RR=0.34 [0.12, 0.99]; p=0.05; I(2)=0%) as compared to the control group. No significant differences were observed between tocilizumab and control group in intensive care unit admissions (RR=0.73 [0.15, 3.59]; p=0.70; I(2)=60%) and risks of post-drug infection (RR=1.29 [0.41, 4.04]; p=0.66; I(2)=88%). In terms of efficacy outcome, improved oxygen saturation (RR=1.13 [1.04, 1.65]; p=0.02; I(2)=0%) was reported to be markedly significant in tocilizumab patients when compared with the standard care group. Conclusions Our results based on pooled studies show tocilizumab to be safe and efficacious in reducing mortality among critically ill COVID-19 patients. However, due to the limited number of observational studies, the positive findings should be viewed cautiously and warrant further investigation.