Effectiveness of rituximab in reducing relapse among Filipino neuromyelitis optica patients

Abstract

Neuromyelitis optica (NMO) is an autoimmune disease with a relapsing progressive course, which result to disability. Recent evidence points to repeated treatment with Rituximab as effective in reducing relapse rates. Currently, there is no local data regarding the effectiveness of Rituximab in adult Filipino patients. A retrospective cohort study of Filipino patients diagnosed with NMOSD and treated with at least 1 Rituximab infusion and a minimum of 6 months follow-up from August 2013 until September 2018 in a private tertiary hospital was done through records review. Patients who were lost to follow-up for 2 years were excluded. The primary outcome was the effectiveness of rituximab, defined based on the comparison of Annualized Relapse Rate (ARR) before and after Rituximab infusion. Seroconversion of anti-aquaporin 4 antibody and the safety profile of Rituximab were secondary outcomes. Among 23 qualified patients, 21 (91.3%) were female. The mean age of the participants was 46.1 years old.The number of patients relapse-free during rituximab treatment was 69.5%. The mean annualized relapse rate (ARR) pre- Rituximab was 16.9 compared to 2.4 in an international study while the mean ARR post-Rituximab was 1.6 compared to 0.1 (p-value of 0.001).There was 1 patient who was initially seropositive then later converted to seronegative at the last follow-up. No adverse effects were reported. Rituximab was effective in reducing relapse rates among Filipino NMOSD patients with no reported adverse effects.