In 2003, the use of high-dose immunoglobulin (intravenous immunoglobulin, or IVIG, therapy) was approved for health insurance coverage in patients with acute Kawasaki disease. Since then, the incidence of coronary lesions has been decreasing in patients with Kawasaki disease. However, about 20% of patients fail to respond to IVIG therapy, and the majority of patients who develop coronary lesions as a complication of Kawasaki disease are IVIG-resistant cases. Because of this, there is a need to establish a new therapeutic strategy for patients with severe Kawasaki disease.
IVIG plus steroid combination therapy has been attracting attention in recent years both as an additional treatment for IVIG-resistant patients and as an initial treatment. With the generous support of numerous institutions, including the Kanto Kawasaki Disease Study Group, the Japanese Ministry of Health, Labour and Welfare, and the University Hospital Medical Information Network, we have decided to conduct a prospective, randomized, controlled trial of the efficacy of initial immunoglobulin plus prednisolone combination therapy for severe Kawasaki disease. Based on data from previous studies, we calculated that 392 patients with severe Kawasaki disease were needed to conduct the research. Because patients with severe Kawasaki disease account for 30% of all patients with the disease and the entry rate was set at 50%, we needed to enroll 2400 patients with acute Kawasaki disease. We thus decided on a plan to complete the clinical study within a 3-year period by obtaining the cooperation of a large number of hospital physicians. By conducting this study, we hope to establish a new treatment strategy for the initial treatment of Kawasaki disease. As the country where Kawasaki disease was first detected, we in Japan feel a special responsibility to share these findings with the rest of the world. I would like to take this opportunity to ask you for your active cooperation and participation in this study.