RecruitingPhase 1Biological interventionObe-cel in Refractory Progressive Forms of Multiple SclerosisThe main purpose of this study is to evaluate if obe-cel is safe or causes any side effects in adults with refractory progressive MS. The study also plans to assess if obe-cel can show early signs of efficacy in MS. The trial includes only 1 group of participants (single-arm). The study population comprises participants with progressive forms of MS, not responsive to highly effective therapies. Upon confirmation of study eligibility, participants will receive chemotherapy (used here for lymphodepletion) over 1 to 3 days in preparation for receiving a single obe-cel infusion. Participants will be checked closely in the 28 days following obe-cel treatment. After this, participants will be monitored to evaluate safety and efficacy up to 24 months.