ARTIOS

Treatment tested

• Ofatumumab

  B-lymphocyte antigen CD20 binding agent

Other measures (4)

Inclusion Criteria: * Diagnosis of MS according to the 2017 Revised McDonald criteria * Relapsing MS: relapsing forms of MS (RMS) including RMS and secondary progressive MS (SPMS) * Disability status at screening defined by Expanded Disability Status Scale (EDSS) score of 0 to 4 (inclusive) * MS treatment history with a maximum of 3 Disease Modifying Therapies (DMTs), where all fumarates are considered as one DMT * Subject transitioning from either any fumarate-based RMS approved therapies, such as dimethyl fumarate (DMF) or diroximel fumarate (DRF), or fingolimod which was administered for a period of at least 6 months, as their last DMT before first study drug administration * Breakthrough disease activity while the participant was adequately using fumarates or fingolimod prior to transitioning for a minimum of 6 months as evidenced by one or more clinically reported relapses or one or more signs of Magnetic Resonance Imaging (MRI) activity (e.g. Gd+ enhancement, new or enlarging T2 lesions) * Neurologically stable within one month prior to first study drug administration Exclusion Criteria: * Subjects with primary progressive MS or SPMS without disease activity * Subjects meeting criteria for neuromyelitis optica * Disease duration of more than 10 years since diagnosis * Pregnant or nursing (lactating) women * Women of child-bearing potential unless they are using highly effective forms of contraception during dosing and for at least 6 months after stopping study medication * Subjects with active chronic disease of the immune system other than MS or with immunodeficiency syndrome * Subjects with active systemic bacterial, fungal or viral infections (such as hepatitis, HIV, COVID-19), or known to have Acquired Immunodeficiency Syndrome (AIDS) * Subjects with neurological symptoms consistent with Progressive Multifocal Leukoencephalopathy (PML) or with confirmed PML * Subjects at risk of developing or having reactivation of syphilis or tuberculosis (e.g. subjects with known exposure to, or history of syphilis, or active or latent tuberculosis, even if previously treated), as confirmed by medical history or per local practice * Subjects with active hepatitis B and C disease, assessed locally * Have received any live or live-attenuated vaccines within 4 weeks prior to first study drug administration * Have been treated with medications as specified or within timeframes specified (e.g. corticosteroids, ofatumumab, rituximab, ocrelizumab, alemtuzumab, natalizumab, daclizumab, cyclophosphamide, teriflunomide etc.) * Subjects suspected of not being able or willing to cooperate or comply with study protocol requirements in the opinion of the investigator

Open-label study to evaluate the effectiveness of treatment with ofatumumab in subjects transitioning from any fumarate-based RMS approved therapy or fingolimod due to breakthrough disease.