Tocilizumab for the Treatment of Intravenous Immunoglobulin-Resistant Kawasaki Disease in Children: Two Case Reports and Literature Review

Purpose: The treatment of intravenous immunoglobulin-resistant Kawasaki disease remains challenging. We report the clinical course and extended follow-up of two cases of intravenous immunoglobulin-resistant Kawasaki disease successfully treated with tocilizumab. This report includes a summary of the global literature on the use of tocilizumab for the treatment of Kawasaki disease. Case Presentation: Two children with intravenous immunoglobulin-resistant Kawasaki disease treated with tocilizumab at our institution since 2022 were retrospectively analyzed. Case 1 presented with complete Kawasaki disease manifestations. Despite intravenous immunoglobulin and glucocorticoid treatment, the condition remained uncontrolled. Cyclosporine did not result in improvements, and interleukin-6 levels increased. The fever subsided within 24 h after tocilizumab administration. The coronary artery dilation had returned to normal at day 77; however, an urticarial rash was observed following the third tocilizumab dose. Case 2 exhibited complete Kawasaki disease manifestations, complicated by a giant coronary artery aneurysm. The fever persisted despite treatment with aspirin, intravenous immunoglobulin, and glucocorticoids, and interleukin-6 levels increased markedly. The fever resolved within 24 h following tocilizumab administration. During a 3-year follow-up, no adverse drug reactions were observed and the dilated coronary artery decreased in size. Among the 14 patients reviewed in the literature, 10 had significantly elevated interleukin-6 levels. All patients achieved rapid fever resolution (within 48 h) following tocilizumab administration and favorable coronary outcomes: most (12/14) showed regression of dilation or no dilation during follow-up. Only one patient developed anaphylaxis after a one-time administration. Conclusion: Tocilizumab could be considered a potential therapeutic option for intravenous immunoglobulin-resistant Kawasaki disease. It is advisable to closely monitor interleukin-6 levels and coronary artery parameters throughout the clinical course, while maintaining a heightened awareness of the possible adverse events related to tocilizumab treatment.