AstraZeneca announced the official launch of the long-acting C5 complement inhibitor Ultomiris (generic name: reslizumab injection) in China. It is indicated in combination with conventional therapy for the treatment of adult patients with generalized myasthenia gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody-positive and neuromyelitis optica spectrum disorder (NMOSD) who are anti-aquaporin 4 (AQP4) antibody-positive. As a long-acting C5 complement inhibitor, reslizumab provides immediate, complete, and sustained inhibition of complement activation. It works by targeting the terminal complement C5 activation in the immune system. Reslizumab has recently been approved in China for the treatment of selected adult patients with gMG (April 2025) and NMOSD (August 2025). With the commercial launch of reslizumab in China, these patients will receive a long-acting complement inhibitor, potentially improving the quality of life of gMG patients and potentially bringing relapse-free outcomes to NMOSD patients.