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Article History

Received: 22 February 2026

Revised: 23 April 2026

Accepted: 13 May 2026

First Online: 3 June 2026

Declarations

:

: J.F.H.: Research funding (paid to his institution): Ad Scientiam, Alexion, argenx, AstraZeneca Rare Disease, Cartesian Therapeutics, Centers for Disease Control, and Prevention, MGFA, Merck EMB Serono, Muscular Dystrophy Association, NIH, NMD Pharma, PCORI, and UCB Pharma; Consulting fees: Alexion AstraZeneca Rare Disease, Amgen, Biohaven Ltd, CoreEvitas, Curie.bio, Hansa Biopharma, Japan Tobacco Company, Kyverna Therapeutics, Merck EMB Serono, Novartis Pharma, Regeneron Pharmaceuticals, Sanofi US, TG Therapeutics, Toleranzia AB, and UCB Pharma; Speaker fees: AcademicCME, CheckRare CME, PeerView CME, Physicians’ Education Resource (PER) CME, PlatformQ CME; Non-financial support: Alexion AstraZeneca Rare Disease, argenx, Biohaven Ltd, Cartesian Therapeutics, Toleranzia AB, and UCB Pharma. Stock dividends (in family trust): Bristol Meyer Squibb, GlaxoSmithKline, Johnson & Johnson; DSMB/Advisory Boards: Alexion AstraZeneca Rare Disease, Amgen, Biohaven Ltd, CoreEvitas, Hansa Biopharma, Japan Tobacco Company, Kyverna Therapeutics, Novartis Pharma, Regeneron Pharmaceuticals, Toleranzia AB, and UCB Pharma. S.H.: Alexion, argenx, Grifols, Johnson & Johnson, Kyverna, Merck, Roche, and UCB Pharma. S.A.: Alexion, Alnylam, Amgen, Amicus, argenx, AstraZeneca, Biogen, Janssen, LFB, Pfizer, Roche, Sanofi, and UCB Pharma. J.L.D.B.: Alexion, Alnylam Pharmaceuticals, Amgen, Amicus, argenx, Biogen, CSL Behring, Janssen, Roche, Sanofi Genzyme, and UCB Pharma. J.B., E.B., and R.K.: full-time employees of argenx with stock or stock options. J.V.: Alexion, Amgen, Amicus, Arvinas, Biogen, Fulcrum Therapeutics, Genethon, Janssen, Lupin, Merck, ML Biopharma, Novartis, Pfizer, Regeneron, Roche, Sanofi Genzyme, Sarepta Therapeutics, and UCB Pharma. A.M. received speaker’s honoraria, served as an advisor board/DSMB member and consultant, and has received research grants (paid to his institution) from Alexion, AstraZeneca Rare Disease, Amgen, argenx, Axunio, Desitin, Genpharm, Grifols, Hormosan, Immunovant, Johnson & Johnson, Merck, Novartis, Octapharma, Regeneron, Sanofi, and UCB. He served as chairman and member of the medical advisory board of the German Myasthenia.

: The protocol and amendments were approved by the institutional review board or ethics committee at each participating center (for full list, see Supplementary Table 1) in accordance with the International Conference on Harmonisation (ICH) of Good Clinical Practice (GCP), the principles of the Declaration of Helsinki, and other applicable local ethical and legal requirements.

: All patients provided written informed consent before starting the study.