To the Editor No evidence of disease activity (NEDA) is becoming an important secondary outcome measure in multiple sclerosis (MS) clinical trials. In this context, the article by Rotstein and colleagues,1 demonstrating that NEDA at 2 years has potential prognostic significance, is timely. Interestingly, the authors1 found a dissociation between clinical and magnetic resonance imaging (MRI) disease activity, raising the question of whether the lack of disease progression truly reflects evidence of absence or absence of evidence.
Sloane JA, Mainero C, Kinkel RP. No Evidence of Disease Activity in Multiple Sclerosis. JAMA Neurol. 2015;72(7):835-836. doi:10.1001/jamaneurol.2015.0587