Comparison of prednisolone monotherapy vs. tacrolimus combination in NMOSD: Efficacy, safety, and optimal therapeutic timing.

Tacrolimus (TAC) has been considered an effective treatment for neuromyelitis optica spectrum disorder (NMOSD), a neuroinflammatory disease associated with aquaporin-4 antibodies. This retrospective cohort study aimed to assess the efficacy and safety of TAC-based therapies compared with prednisolone (PSL) monotherapy in preventing relapse and optimizing treatment timing. Forty-one patients with NMOSD treated at Hiroshima University Hospital between 2015 and 2022 were included in the analysis. These patients met the 2015 International Consensus Diagnostic Criteria and received either TAC or PSL for at least 6 months. Patients treated with TAC, either alone or in combination with PSL, demonstrated significantly lower relapse rates (p = 0.002) and annualized relapse rates (p = 0.027) than those treated with PSL monotherapy. Furthermore, TAC recipients required lower PSL doses (p = 0.029), and two patients successfully discontinued PSL entirely. Importantly, initiating TAC within 3 months of starting PSL further reduced relapse rates compared with later initiation (p = 0.040). Although two TAC-treated patients experienced relapses leading to therapy discontinuation, no adverse events led to therapy cessation. These findings suggest that TAC may suppress relapse rates and enable reduction of PSL dosage, without apparent safety concerns. Early TAC initiation may also be associated with lower relapse rates.