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Article History

Received: 3 December 2025

Accepted: 29 January 2026

First Online: 10 March 2026

Declarations

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: The authors declare the following potential conflicts of interest: Bruno Brochet has received consultancy fees and speaker fees from Merck and Sanofi. Dawn Langdon has participated in speaker bureaus for Almirall, Bayer, Biogen, Bristol Myers Squibb (BMS), Merck, Novartis, Roche, Sanofi, and Teva; has received consultancy fees from Bayer, Biogen, BMS, Merck, Novartis, and Teva; and has received research grants from Bayer, Biogen, Merck, and Novartis. Dawn Langdon is an Editorial Board member of Neurology and Therapy , and was not involved in the selection of peer reviewers for the manuscript nor any of the subsequent editorial decisions. Eva Kubala Havrdova received financial support for conference travel, and/or speaker honoraria, and/or research support, and/or consultant fees from Actelion, Biogen, Celgene, Merck, Novartis, Roche, Sanofi, and Teva. She has been supported by the Czech Ministry of Education—project Cooperatio LF1, research area Neuroscience—and by the General University Hospital in Prague project MH CZ-DRO-VFN64165. Jeanette Lechner-Scott has received travel compensation from Biogen, Merck, and Novartis. Her institution receives honoraria for talks and advisory board commitments as well as research grants from Biogen, Merck, Novartis, and Roche. Xavier Montalban's institution has received compensation for lecture honoraria and travel expenses, participation in scientific meetings, clinical trial steering committee membership, or clinical advisory board participation in recent years from AbbVie, Actelion, Alexion, AstraZeneca, Autolus, Bial PD, Biogen, BMS/Celgene, Genzyme, Hoffmann-La Roche, Immunic Therapeutics, Indivi, Janssen Pharmaceuticals, Juvisé Pharmaceutical, Lilly, MedDay, Medscape, Merck, Mylan-Viatris, Nervgen, Neuraxpharm, Novartis, PeerVoice, Rewind Therapeutics, Samsung-Biosys, Sandoz, Sanofi-Genzyme, Teva Pharmaceutical, TG Therapeutics, Zenas Biopharma, Excemed, ECTRIMS, MSIF, and NMSS, or any of their affiliates. Francesco Patti has received personal compensation for speaking activities or serving on advisory boards from Alexion, Almirall, Biogen, BMS, Johnson & Johnson, Merck, Novartis, Roche, and Sanofi. He has also received research grants from Alexion, Almirall, the Italian Ministry of Health, Merck, MIUR, Novartis, Roche, and Sanofi. He is Associate Editor of Frontiers in Neurology . Francesco Patti is an Editorial Board member of Neurology and Therapy . He was not involved in the selection of peer reviewers for the manuscript nor any of the subsequent editorial decisions. Fredrik Piehl has received research grants from Janssen, Merck, and Sanofi; fees for serving as a member of the DMC in clinical trials with Lundbeck, Parexel, and Roche; and fees for the preparation of witness statements for Novartis. Alessandra Solari has served on advisory boards for Almirall and Merck and has been invited to speak on behalf of the same companies. She has also received research grants from the Italian MS Society. Raymond Hupperts has received institutional research grants and fees for lectures and advisory boards from Biogen, Merck, and Sanofi. Nektaria Alexandri, Annette Lehn, and Andrzej Smyk are employees of Merck Healthcare KGaA, Darmstadt, Germany. Krzysztof Selmaj has received honoraria for speaking, consulting, and serving on advisory boards for Biogen, Celgene (BMS), Merck, Novartis, Roche, and TG Therapeutics.

: The CLARIFY-MS study was conducted in accordance with the principles outlined in the Declaration of Helsinki and the International Council for Harmonisation Guidelines for Good Clinical Practice. This study was approved by independent ethics committees or institutional review boards at each study site. Participants provided written informed consent prior to the initiation of any study-related activities. Details of all institutional review boards and ethics committees are available in Supplementary Table S5.