Background: Neuromyelitis optica (NMO) is an inflammatory disorder of the central nervous system predominantly affecting the optic nerves and spinal cord with severe relapses resulting devastating disability. Rituximab is an anti CD20 monoclonal antibody that has shown efficacy in decreasing the relapse rate in some NMO patients. Objective: Report five NMO patients who had relapses within two weeks of their first rituximab infusion. Methods: Chart review of rituximab-treated NMO patients. Results: All patients met the diagnostic criteria for NMO. Five of nine patients treated with rituximab relapsed within two weeks of their first infusion. All were women. Their mean age at the time of rituximab treatment was 45.5 years( range 19-64) and mean disease duration 9 years (range 3-18). They had a total of 49 relapses (range 3-18). Three patients developed transverse myelitis within two weeks and one patient had optic neuritis within one week of the infusion. The fifth patient had decreased level of consciousness two days after rituximab infusion with a brain MRI showing multiple new gadolinium enhancing lesions. All patients had significant recovery after plasmapheresis. Conclusions: Five of nine rituximab-treated NMO patients had a relapse within two weeks of their first rituximab infusion. All these patients had highly active disease prior to the initiation of rituximab treatment and therefore their post-infusion relapse could be attributed to the aggressive nature of their disease and not necessarily to being precipitated by rituximab, however the temporal association raises concerns of causation. A recent abstract on NMO patients reported a transient increase in potentially pathogenic anti aquaporin 4 antibodies along with an associated increase in serum B cell activating factor (BAFF) levels about two weeks post rituximab infusion, which might explain the increased propensity to relapses in the immediate post infusion period. Lack of response to rituximab in NMO patients has been reported as well, especially in patients with longer disease duration which suggests that perhaps with longer duration, the immunopathogenetic mechanisms expand and the disease becomes less amenable to targeted B cell therapies. Another plausible explanation for lack of efficacy could be the inherently different disease mechanisms in NMO patients. Further studies are needed to better elucidate the exact diseases mechanisms and to define best treatment strategies for NMO.
Read More: Paradoxical response after first rituximab infusion in patients with neuromyelitis optica