Biotine is proposed by neurologists to patients with a progressive form of Multiple sclerosis (MS) in the context of a nominative temporary authorization for use (TAU) as a disease-modifying treatment for their MS. A recent study showed that with this treatment, more patients experienced an improvement after one year in comparison with patients given a placebo.

The objective of this study is to identify blood biomarkers to determine good responders as early as possible. In addition, the blood parameters studied will make it possible to better understand the mechanisms of action, that have a beneficial effect on multiple sclerosis.

The management of patients will not be modified: same number of consultations (at the prescription, at 3 months, at 12 months), same clinical examination, and the same number of blood samples (at the prescription, at 3 months, and at 12 months).

Inclusion Criteria:

• 18 to 65 years old
• inactive progressive form of MS according to the Lublin classification and recorded in the Burgundy EDMUS database
• Patients with health insurance cover
• Patients who have provided written informed consent (OFSEP)

Exclusion Criteria:

• Patients unable to understand the information sheet
• Patients with remittent or active progressive MS
• Patients with a change in the disease-modifying treatment within the previous 3 months
• Patients treated with corticosteroids in the month before inclusion
• Impossibility to provide patients with the necessary information
• Patients in custody
• Patients under guardianship

25 patients with progressive (primary or secondary) MS will be encountered over time during consultations at Dijon CHU. Treatment with biotine will be proposed to patients and a nominative TAU will be requested.