Conditions: Neuromyelitis Optica Spectrum Disorder
Keywords: neuromyelitis optica spectrum disorder azathioprine rituximab clinical trial annual relapse rate expanded disability status scale
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 86
Healthy volunteers: no

Brief summary:
The purpose of this study is to compare annual relapse rate, expanded disability status scale, and side effects of azathioprine and rituximab in patients with neuromyelitis optica spectrum disorder during a one year follow up through a randomized clinical trial.

Detailed description:
Neuromyelitis Optica Spectrum Disorder (NMO-SD) is a recurrent inflammatory demyelinating disease affecting the central nervous system. The disease is clinically recognized by optic neuritis and transverse myelitis and is associated with high risk of mortality. Each attack worsens patients' disability. This means that after 5 years of the disease onset, half of patients need to use wheelchair and approximately 50% of them become blind.

Considering that the disease can be disabling for patients, the maintenance treatment should be applied in addition to treatment of acute attacks, in order to prevent future recurrences. Acute attacks are usually treated with high doses of intravenous corticosteroids. Plasmapheresis is also used when patients fail to response to corticosteroids. B lymphocyte inhibitors are used as the maintenance therapy in these patients. First line therapeutic medications include azathioprine and rituximab which are being recommended for long term therapy and second line medications include methotrexate and mycophenolate mofetil.

Azathioprine is an immune-modulatory agent which is available in the oral form and don't require hospitalization to be administered, however, because of side effects such as bone marrow suppression and hepatotoxicity, periodic check of blood cells and liver enzymes are needed. Rituximab is a cluster of differentiation antigen 20 inhibitor which leads to decreased B lymphocytes and antibody in patients. This medication is only available in the injectable form and needs hospitalization to be administered. Close monitory is needed during the administration considering severe side effects such as allergic reactions and respiratory distress. However, laboratory tests are not needed in patients taking rituximab although it is more expensive than azathioprine. No clinical trial has been performed previously to compare clinical efficacy of these two drugs in NMO-SD patients. Therefore, we aimed to compare their efficacy through a randomized clinical trial.

Arms:
arm 1: Patients in this group will receive 50 mg of azathioprine, two times each day and gradually increased to maximum dose of 3 g daily with the aim of lymphocytes count less than 1500. arm 2: Patients in this group will receive 1g of Rituximab in 500 cc normal saline serum through intravenous infusion with two weeks intervals (as one course) and each course of treatment is repeated every 6 months.

Interventions: intervention 1: Azathioprine intervention 2: Rituximab
Intervention descriptions: intervention 1: Patients are started with Azathioprine 50 mg tablets, taken orally twice a day. The medication dose is increased gradually with the aim of lymphocytes count bellow 1500 and to the maximum dose of 3 g Azathioprine per day. Cell blood count is checked once a week in the first month of treatment, once every two weeks in the second month of treatment, and monthly in the third month of treatment to make decision about medication dose. intervention 2: Patients will receive 1 g of Rituximab (two vials of RediTux 500 mg/50 ml) in 500 cc normal saline serum through intravenous infusion and this will be repeated two weeks later. This cycle will be repeated every 6 months.

Protocol document: