A Multi-Center, Open-Label Long-Term Extension Study of CNM-Au8 In Patients With Stable Relapsing Multiple Sclerosis

Inclusion Criteria: * Participants must have completed study CNMAu8.201. * Able to understand and give written informed consent. Exclusion Criteria: * Lack of treatment compliance during participation in the CNMAu8.201 (VISIONARY-MS) study. * Positive pregnancy test. * Any history of previous malignancy, with the exception of basal cell carcinoma of the skin or in situ carcinoma of the cervix, post documented full resections, with clean margins. * Based on the Investigator's judgment, any concurrent chronic or acute illness or unstable medical condition that could confound the results of safety assessments, increase risk to the participant, or lead to difficulty complying with the protocol; any untreated or unstable psychiatric disease including depression, bipolar and psychosis. * Participant is considered a suicide risk in the opinion of the Investigator, has previously made a suicide attempt, or is currently demonstrating active suicidal ideation. Following clinical and serology sample analysis conducted at the end-of-study visit for CNMAu8.201 (VISIONARY-MS), participants may be removed from this long term extension study if any of the following criteria are met, at the discretion of the Medical Monitor and/or Sponsor's Medical Representative: * Positive serology for viral hepatitis B and/or C and/or human immunodeficiency virus (HIV). * Abnormal liver function tests (aspartate aminotransferase \[ASAT\] or alanine aminotransferase \[ALAT\] \> 2x upper limit of normal range (ULN) or total bilirubin \> 2x ULN or alkaline phosphatase (AP) \> 3x ULN). * Participants with clinically significant hepatic or renal dysfunction or clinical laboratory findings that would limit the interpretability of change in liver or kidney function (e.g., glomerular filtration rate \< 40 mL/min \[based on creatinine clearance according to Cockcroft-Gault equation\]), or those with low platelet counts (\<150 x 109 per liter) or eosinophilia (absolute eosinophil count of ≥500 eosinophils per microliter) at the EOS visit for CNMAu8.201 (Visionary-MS).