Low-dose tacrolimus in treating neuromyelitis optica spectrum disorder

Background: The value of tacrolimus (TAC) in neuromyelitis optica spectrum disorder (NMOSD) has not been fully demonstrated. In this study, we aimed to explore the effectiveness and safety of low-dose TAC in treating NMOSD. Methods: Patients with NMOSD taking low-dose TAC were retrospectively collected. We compared the annualized relapse rate (ARR) before and after the initiation of TAC. Cox proportional hazards model was used to identify the risk factors of relapse during TAC treatment with their hazard ratio (HR). The effectiveness and safety of TAC were also compared with a group of patients on mycophenolate mofetil (MMF). Results: A total of 42 NMOSD patients taking TAC were included, with the administered dose of 1-3mg/d. The ARR (1, 0-3) after the initiation of TAC decreased significantly compared to those before TAC treatment (0, 0-2, p < 0.001). The most common adverse events (AEs) observed included alopecia (23.8%), tremor (16.7%) and elevated blood glucose (11.9%). Multivariate Cox proportional hazards model exhibited that patients with higher baseline ARR (HR: 1.77, 0.76-4.16) and Expanded Disability Status Scale (EDSS) score (HR: 1.79, 1.20-2.68) were at a higher risk for relapse during TAC treatment (p = 0.188 and 0.004, respectively). We did not observe significant difference between TAC-treated and MMF-treated patients regarding the risk of relapse (p = 0.323). Conclusion: Low-dose TAC was an effective and tolerable choice in treating NMOSD.