Effect of subcutaneous vs. intravenous tocilizumab in patients with severe COVID-19: a systematic review.

Objective: To systematically evaluate the efficacy of subcutaneous tocilizumab in the treatment of patients with severe COVID-19 and provide evidence for the rational use of subcutaneous tocilizumab in patients with severe COVID-19.

Methods: This meta-analysis was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We searched the Cochrane Library, PubMed, Embase, CNKI, SinoMed, and Wanfang Medical Network electronic databases up to 11 January 2023 to identify relevant studies. To obtain the most recent clinical studies of subcutaneous injection of tocilizumab for the treatment of patients with severe COVID-19, we also searched the preprint platforms medRxiv and ChinaXiv. Furthermore, we searched ClinicalTrials.gov for relevant unpublished studies. The studies were screened based on the PICOS principle. The included studies were classified and evaluated for quality based on research type. The RevMan 5.3 software was used to conduct the meta-analysis, and a descriptive analysis was performed to examine relevant outcome indicators.

Results: Five observational studies were obtained, involving a total of 498 patients (240 patients in the subcutaneous injection group and 258 patients in the intravenous injection group). All of the studies were of the highest quality. The meta-analysis of the included studies revealed that the mortality rate of patients who received subcutaneous tocilizumab to treat COVID-19 was not significantly higher than that of the intravenous injection group [23.3% (45/193) vs. 18.4% (39/212), RD = 0.06, 95% CI = - 0.01 ~ 0.13, P = 0.11]. Furthermore, there was no significant difference in the proportion of patients requiring mechanical ventilation between the two groups [24.5% (35/143) vs. 22% (35/159), RD = 0.03, 95% CI = - 0.07 ~ 0.12, P = 0.56].

Conclusions: The meta-analyses do not provide evidence that subcutaneous and intravenous tocilizumab formulations for the treatment of severe COVID-19 infection differ regarding their effectiveness. Considering that the meta-analyses cannot replace an appropriately powered non-inferiority study, subcutaneous formulations still need to be used with caution and only when intravenous formulations are in short supply. At present, there is a lack of randomized controlled trials of subcutaneous injection of tocilizumab for the treatment of severe COVID-19, and more clinical research should be conducted.