Researchers discovered that a reduced dose of rituximab as initial therapy reduces the risk of relapse compared to mycophenolate mofetil and is also better tolerated than azathioprine in patients with aquaporin-4 (AQP4) antibody-positive neuromyelitis optica spectrum disorder (NMOSD), as published in the European Journal of Neurology.

Researchers assessed 353 patients with NMOSD with the occurrence of relapse as the primary outcome and drug persistence, annual relapse rates, disabilities, and adverse events as secondary outcomes.

“Our investigation entails the largest AQP4-antibody-positive cohort to date to compare the efficacy and safety among conventional and widely-available therapies in NMOSD,” the authors wrote.

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“The main findings were: (1) [rituximab] was superior to [azathioprine] and [mycophenolate mofetil] to reduce the risk of relapse; (2) Persistence on [rituximab] and [mycophenolate mofetil] was superior to [azathioprine]; (3) The incidence of overall [adverse events] during treatment was lower in [rituximab] and [mycophenolate mofetil] groups than in the [azathioprine] group.”

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In previous studies, annual relapse rates were the main measure of the efficacy of NMOSD treatment. However, given the strong association between relapses and the accumulation of disability in NMOSD, the research team employed “time to first relapse” as a measure of overall disease activity suppression, as has been used in several recent randomized controlled trials and cohort studies. In this context, they found that rituximab more effectively reduced the risk of relapse than azathioprine in their study cohort.

In terms of drug persistence rate, rituximab performed significantly better than azathioprine, and there was no significant difference between rituximab and mycophenolate mofetil. Finally, in assessing adverse events based on percentage incidence and adverse event rates per 10 patient-years of drug exposure, rituximab was better tolerated by patients than azathioprine. However, given certain genetic differences between Asians and Caucasians, the authors caution that all of the study results might not be generalizable to other ethnicities.


Huang W, Wang L, Xia J, et al. Efficacy and safety of azathioprine, mycophenolate mofetil and reduced dose of rituximab in neuromyelitis optica spectrum disorder. Eur J Neurol. Published online April 10, 2022. doi:10.1111/ene.15355