AIM: To evaluate the efficacy of mycophenolate mofetil(MMF)on the prevention of relapse and visual prognosis of patients in neuromyelitis optica spectrum disorders(NMOSD)with AQP4 antibody positive optic neuritis.

METHODS: We retrospectively reviewed 11 patients with initial diagnosis of NMOSD and AQP4 antibody positive optic neuritis from January 2017 to December 2019. Among the 11 patients, 3 were male and 8 were female. The unique core clinical manifestation of NMOSD was optic neuritis. The onset age was 36.3±6.0(27-47)years old. Duration of the disease was 3.4±1.4(2.2-6.8)a. MMF was added in the relieving period of NMOSD for 1a or over 1a. Annualized relapsing rate(ARR), best corrected vision activity(BCVA)and adverse reactions of MMF were recorded.

RESULTS: The median time of MMF treatment was 18(12, 36)mo. The ARR was 0.66/a at baseline and 0.16/a after the treatment. There were 91% of the patients had decreased ARR and 82% of them had no clinical relapse. The patients had significant improvement on ARR after MMF treatment(P<0.05 ). In total, there was no significant difference between the mean BCVA after treatment and that at baseline(P>0.05). Of the 11 patients, 3 patients had side effects(27%), including 1 patient with elevated liver transaminase(9%), and 2 patients with mild gastrointestinal reaction(18%)during follow-up period. None of them discontinued MMF due to adverse events.

CONCLUSION: MMF treatment for AQP4 antibody positive NMOSD can reduce the ARR of optic neuritis to a certain extent and protect the visual function of patients.