Safety and effectiveness of intravenous abatacept for polyarticular-course juvenile idiopathic arthritis: An all-case postmarketing surveillance study.

Background: In 2018, intravenous abatacept was approved for the treatment of refractory polyarticular-course juvenile idiopathic arthritis (JIA) in Japan. However, reports describing the effectiveness and safety of abatacept in clinical practice in Japanese patients with refractory polyarticular-course JIA are limited. Therefore, this postmarketing surveillance study aimed to evaluate the real-world safety and effectiveness of abatacept in Japanese pediatric patients with refractory polyarticular-course JIA.