The aim of this study is to identify whether it is possible to safely discontinue treatment in relapsing-onset MS patients who have shown no evidence of active inflammation in the years prior to inclusion clinically and/or radiologically. The secondary objectives address the questions whether the discontinuation of first-line treatment has an effect on disability progression and whether the discontinuation of first-line treatment improves the quality of life for the patient. Furthermore, blood collections will be included to assess whether it is possible to retrospectively predict possible return of inflammatory activity with biomarkers such as neurofilament light (NFL) or patient characteristics such as disease activity prior to disease modifying therapy (DMT). In case of emerging disease activity after the cessation of therapy we will assess if reinitiation will lead to NEDA again, and if there are long-term consequences. If possible, post-hoc analysis are performed for the different types of treatment compounds.

Inclusion Criteria:

• Minimum age of 18 years
• Ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use protected health information (PHI) in accordance with national and local privacy regulations.
• Definite diagnosis of relapsing-onset MS according to the revised McDonald 2017 criteria
• Treatment with one of the first-line DMTs: any of the interferons, glatiramer acetate, dimethylfumarate, teriflunomide
• Complete absence of inflammatory activity (no objectively defined and confirmed relapses, no significant number (2 or more) of new-T2 lesions and no contrast-enhancing lesions) for 5 consecutive years under first-line treatment

Exclusion Criteria:

• A switch between first-line disease modifying therapy over two years prior to inclusion, in case the switch has been due to in effectivity of the first DMT.
• Women who want to discontinue medication because of a pregnancy wish and women who are pregnant or expect to become pregnant during the study period
• Patients that have previously used interferon-beta and have been tested positive for neutralizing antibodies (NAbs).