Efficacy and safety of long-term treatment with low-dose rituximab for neuromyelitis optica spectrum disorder

Abstract

Objective To evaluate the efficacy and safety of repeated treatments with low-dose rituximab for relapsing neuromyelitis optica spectrum disorder (NMOSD). Methods A perspective study. 21 patients who were diagnosed with NMOSD one year ago were recruited for rituximab treatment. Of 21 patients, one was male, 20 were females. Onset age was 10 - 51 years, the mean onset age was (26.2±12.0) years. Duration of disease was 2.3 - 25.8 years, the mean duration was (9.2±5.9) years. Best corrected vision activity(BCVA), expanded disability status scale (EDSS), annualized relapsing rate (ARR) were valued to investigate the efficacy and safety of repeated treatments with low-dose rituximab. The BCVA was examined using Snellen chart, and converted to logMAR. The mean BCVA was 1.13±1.09, the mean BCVA in better eyes was 0.4±0.68, the mean BCVA in latter eyes was 1.87±0.90. The mean EDSS was 3.09±0.70. The mean ARR was 1.04±0.65. All patients underwent two cycles of RTX treatment. The annually induction treatment was RTX 100 mg per week for 4 weeks. Of 21 patients, 12 patients had treatment within one month after attack. The mean follow-up period was (28.4±4.9) months. The side effects were recorded, BCVA, EDSS, ARR were valued to investigate the efficacy and safety of repeated treatments with low-dose rituximab. Paired t test, independent sample t test and Chi-squared test were used. Results The mean BCVA at last follow-up was 0.62±0.91, the mean BCVA in better eye was 0.62±0.91, the BCVA in latter eye was 1.0±1.01. The mean EDSS was 2.26±1.07. The mean ARR was 0.21 ± 0.3. After the treatment, patient had significant improvement on BCVA in worst eye (t=4.256), ARR (t=2.900), EDSS (t=4.620) with the significant differences (P 0.05). There were 9 patients had relapse, 13 times in total. Of 13 relapses, B lymph cell count was performed in 12 relapses, and the counts were 0.01% - 0.14%. There were no significant difference between relapsed patients and non-relapsed patients on onset age (t=0.67, P=0.51), whether underwent plasma exchange treatment (χ2=1.61, P>0.05), with/without auto-immune antibody ratio (χ2=1.61, P>0.05). Of 21 patients, 8 patients had side effects, including 5 patients with infection, 4 patients with chest congestion, 3 patients with hair losing, 2 patients with skin rashes, headache and short of breath, 1 patient with tinnitus, palpitation and fatigue. Four patients had more than one symptom. Of all patients who had side effects, slowing down the infusion speed of RTX or infusing 5 mg of dexamethasone could relieve the discomfort. Conclusion Lose-dose rituximab reduces the frequency of NMOSD relapses and is well tolerated. Key words: Neuromyelitis optica/drug therapy; Antigens, CD20/administration & dosage; Protective agents; Recurrence