Clinical Effectiveness of Biological Immunomodulators in SARS-CoV-2-Associated Multisystem Inflammatory Syndrome in Children: A Systematic Review.

Background: Although there is consensus to use immunoglobulins and corticosteroids as first-line treatments for multisystem inflammatory syndrome in children (MIS-C), the effectiveness of biological immunomodulators in patients refractory to standard therapy remains unclear. We aimed to outline real-world data on biological immunomodulators.

Method: A literature search using Ovid-Medline, EMBASE, Cochrane CDSR, and KMBASE was conducted from September 2021 to August 2022; certainty of evidence was assessed via GRADE.

Results: Among 258 studies, 10 were selected for analysis, of which 2 were observational studies (with control groups receiving standard therapy of either intravenous immunoglobulins and/or glucocorticoids) and 8 were single-arm studies. In all, 145 patients were treated with biological immunomodulators (anakinra (72; 49%) or infliximab (65; 44%)). In the first observational study, patients in the anakinra group initially exhibited a lower left ventricular ejection fraction than those in the control group. In the second study, patients in the infliximab group required less additional therapy and showed lower newly developed left ventricular dysfunction rate and reduced C-reactive protein levels. The clinical outcomes associated with each biological agent in single-arm studies were not reported individually.

Conclusions: Biological immunomodulators are feasible therapeutic options for refractory MIS-C. Nevertheless, further research is warranted to demonstrate clinical efficacy.