Comparison of efficacy and tolerability of azathioprine, mycophenolate mofetil, and lower dosages of rituximab among patients with neuromyelitis optica spectrum disorder.

OBJECTIVE

To observe and compare the efficacy and tolerability of azathioprine (AZA), mycophenolate mofetil (MMF) and lower dosages of rituximab (RTX) among patients with neuromyelitis optica spectrum disorder.

METHODS

In this prospective cohort, AQP4-IgG-seropositive patients with neuromyelitis optica spectrum disorder (NMOSD) were enrolled and randomly divided into three groups, using AZA, MMF or lower dosages of RTX (defined as 100mg RTX intravenous injection, once per week for 4 consecutive weeks) respectively. Annualized relapse rate (ARR), EDSS scores, CD19+ B-cell counts in peripheral blood, serum AQP-4-IgG titre and drug adverse reactions were compared between three groups.

RESULTS

In the AZA group (n=22), MMF group (n=30) and RTX group (n=20), 54.5%, 60.0% and 65.0% of patients reached a relapse-free state and EDSS score improved in 90.9%, 83.3% and 90.0% of patients respectively. In addition, there was significant reduction in ARR in all the three groups. Reduced dosage of RTX exerted a significant effect in reducing CD19+ B-cell counts (P<0.01). Compared with the AZA group, the MMF group and the RTX group decreased the AQP-4-IgG titre evidently and caused fewer adverse events. Neither the Kaplan-Meier survival curves nor the Cox proportional hazard model indicated a significant difference in relapse among the three groups (P>0.05).

CONCLUSIONS

AZA, MMF and reduced dosages of rituximab are all effective in reducing ARR and improving the clinical symptom of patients with NMOSD. Lower dosages of RTX are more effective than the others in decreasing the CD19 B-cell counts. MMF and reduced RTX decrease AQP-4-IgG titre more and cause fewer adverse events than AZA. However, more multicentre studies are still needed to find more effective therapeutic regimen.