Nikolaos Grigoriadis, MD, PhD, Aristotle University of Thessaloniki, Thessaloniki, Greece, discusses the real-world study comparing the long-term efficacy outcomes of natalizumab versus fingolimod in patients with highly active relapsing-remitting multiple sclerosis (RRMS). Results suggest that natalizumab has superiority concerning relapse and MRI activity outcomes compared to fingolimod. Future studies should investigate the mechanisms that might be highlighted due to the different effects of natalizumab and fingolimod. This interview was conducted during the virtual 2021 World Congress on Controversies in Neurology (CONy).