How long do you maintain a patient with seropositive Neuromyelitis Optica Spectrum Disorder on disease modifying therapy?  

Neuromyelitis optica never goes away, as far as we know. Stopping immunotherapy will likely lead to a relapse at some point. Some meds provide a short "honeymoon" period of durable risk reduction beyond the treatment period - that may include eculizumab according to the phase 2 trial in NMO. But sto...