This study was carried out in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments. Informed consent was obtained from all patients eligible for the study. This protocol, the Informed Consent Forms, any information to be given to the patient, and relevant supporting information, was approved by the IRB/EC of the coordinator center and by all the centers participating to the study.

CGC has received grants for congress participation from Almirall, Biogen Idec, Merck Serono, Novartis, Roche, Sanofi Genzyme, and TEVA. AB received compensation for consulting services and participation in advisory board and travel grants from Almirall, Biogen, Novartis, Roche, Sanofi- Genzyme, and Merck-Serono. VBM declares no conflict of interest. MC received compensation for speaking activities, travel grant, and participation in advisory board from Biogen, Bristol-Myers Squibb, Merck-Serono, Novartis, Roche, and Sanofi-Genzyme. FC has received travel grants from Biogen, Merck, Sanofi-Genzyme, and Roche and research grants from Merck. PC received honoraria as speaker or travel grants to attend national and international conferences or consultation for advisory boards from Alexion, Almirall, Bayer Schering, Biogen, Cellgene-BMS, Merck-Serono, Teva, Roche, Novartis, Sanofi-Genzyme, and Janssen. She is the principal investigator in clinical trials for Roche, Sanofi-Genzyme, and Merck Serono. CC declares no conflict of interest. CrC declares no conflict of interest. MD declares no conflict of interest. MF is Editor-in-Chief of the Journal of Neurology; Associate Editor of Human Brain Mapping, Neurological Sciences, and Radiology; received compensation for consulting services from Alexion, Almirall, Biogen, Merck, Novartis, Roche, and Sanofi; speaking activities from Bayer, Biogen, Celgene, Chiesi Italia SpA, Eli Lilly, Genzyme, Janssen, Merck-Serono, Neopharmed Gentili, Novartis, Novo Nordisk, Roche, Sanofi, Takeda, and TEVA; participation in Advisory Boards for Alexion, Biogen, Bristol-Myers Squibb, Merck, Novartis, Roche, Sanofi, Sanofi-Aventis, Sanofi-Genzyme, and Takeda; scientific direction of educational events for Biogen, Merck, Roche, Celgene, Bristol-Myers Squibb, Lilly, Novartis, and Sanofi-Genzyme; receives research support from Biogen Idec, Merck-Serono, Novartis, Roche, Italian Ministry of Health, Fondazione Italiana Sclerosi Multipla, and ARiSLA (Fondazione Italiana di Ricerca per la SLA). PI has received honoraria for lecturing and participation in advisory boards, and/or travel expenses for attending congresses and meetings from Almirall, Biogen Idec, Merck Serono, Mylan, Novartis, Roche, Sanofi Genzyme, and TEVA. RL declares no conflict of interest. AL declares no conflict of interest. ALu has served as a Biogen, Bristol Myers Squibb, Merck Serono, Novartis, Roche, and Sanofi/Genzyme Advisory Board Member. She received congress and travel/accommodation expense compensations or speaker honoraria from Alexion, Biogen, Merck Serono, Novartis, Roche (2020), Sanofi/Genzyme, and Fondazione Italiana Sclerosi Multipla (FISM). Her institutions received research grants from Novartis and Sanofi/Genzyme. SLF has received honoraria for lecturing and participation in advisory boards, and/or travel expenses for attending congresses and meetings from Almirall, Biogen Idec, Merck Serono, Mylan, Novartis, Roche, Sanofi Genzyme, and TEVA. GL has received honoraria for lecturing and participation in advisory boards, and/or travel expenses for attending congresses and meetings from Almirall, Biogen Idec, Merck Serono, Mylan, Novartis, Roche, Sanofi Genzyme, and TEVA. AGM is an advisory board member of Biogen Idec, Genzyme, Merck-Serono, Novartis, Almirall, Alexion, and Roche and received honoraria for speaking or consultation fees from Alexion, Almirall, Bayer Schering, Biogen Idec, Merck Serono, Novartis, Sanofi-Genzyme, Roche, Janssen, Viatris, and Bristol-Myers Squiibb. She is the principal investigator in clinical trials for Biogen Idec, Merck Serono, Novartis, Roche, Sanofi-Genzyme, and Merck Serono. FM received compensation for speaking activities, travel grant, and participation in advisory board from Biogen, Bristol-Myers Squibb, Novartis, Roche, Sanofi-Genzyme, and Merck-Serono. MM received compensation for consulting services, speaking activities, and participation in advisory board from Alexion, Almirall, Bayer, Biogen, Bristol-Myers Squibb, Celgene, CSL Behring, Novartis, Roche, Sanofi-Genzyme, Janssen, Merck-Serono, and Viatris; he received research support from Biogen, Merck-Serono, Novartis, and Roche. LM received compensation for speaking activities, travel grant, and participation in advisory board from Biogen, Bristol-Myers Squibb, Novartis, Roche, Sanofi-Genzyme, Merck-Serono, Biogen, and Alexion. CP received compensation for speaking activities, travel grant and participation in advisory board from Biogen, Bristol-Myers Squibb, Merck-Serono, Novartis, Roche, Sanofi-Genzyme. SR received compensation for speaking activities, travel grant, and participation in advisory board from Biogen, Bristol-Myers Squibb, Novartis, Roche, Sanofi-Genzyme, Merck-Serono, and Viatris. ST declares no conflict of interest. MT reported receiving speaker honoraria and research grants to her institution from and serving on advisory boards of Biogen, Merck Serono, and Novartis. DV declares no conflict of interest. FP has received honoraria for speaking activities by Almirall, Bayer Schering, Biogen Idec, Merck Serono, Novartis, Roche, Sanofi Genzyme, and TEVA; he also served as advisory board member from the following companies: Bayer Schering, Biogen Idec, Merck Serono, Novartis, Roche, Sanofi Genzyme, and TEVA; he was also funded by Pfizer and FISM for epidemiological studies; he received grants for congress participation from Almirall, Bayer Shering, Biogen Idec, Merck Serono, Novartis, Roche, Sanofi Genzyme, and TEVA.