Mar Tintoré, MD, PhD, Vall d’Hebron University Hospital, Barcelona, Spain, discusses what she thinks is the next big challenge for multiple sclerosis (MS) research. Great developments have been made in the treatment and prevention of MS relapses as well as treat new lesions but Dr Tintoré recommends that understanding the progression of the disease should be the next focus. This interview took place during the European Academy of Neurology 2021 congress.