RESET-MS: A Study to Evaluate the Safety and Efficacy of CABA-201 in Participants With Multiple Sclerosis

Inclusion Criteria The main inclusion criteria include the following: * Able to provide informed consent. * Age ≥18 and ≤60 years of age. * Diagnosis of MS per the revised 2017 McDonald criteria (Thompson et al, 2018). * For participants with relapsing forms of MS only (RMS Cohort): 1. Moderate degree of previously accumulated disability as measured by the Expanded Disability Status Scale (EDSS) 2. Documentation of clinical relapse or a positive historical gadolinium (Gd)-enhancing magnetic resonance imaging (MRI) scan prior to Screening 3. Prior treatment with a high-efficacy therapy or prior treatment failure of oral therapies * For participants with progressive forms of MS only (PMS cohort): 1. Moderate Disability as measured by EDSS 2. Presence of abnormal function on protocol specified EDSS Functional Systems Scale 3. Objective worsening of disease prior to Screening while on standard of care therapy * Clinical stability by vital signs assessment at the time of screening Exclusion Criteria The main exclusion criteria include the following: * History of fulminant MS * Clinically significant concomitant central nervous system pathologies which, in the Investigator's judgement, may confound the ability to interpret study results or complicate identification or evaluation of neurotoxicity, including but not limited to: 1. Any history of seizure disorder, even if well-controlled on antiepileptics 2. History of progressive multifocal leukoencephalopathy * Active, inflammatory autoimmune disorder other than MS requiring immunomodulatory therapies a. Positive human immunodeficiency virus (HIV), hepatitis C virus (HCV) antibody, or hepatitis B surface antigen test, or evidence of active or chronic tuberculosis (TB) at Screening or other chronic viral infections as described in the protocol * Use of the following therapies: 1. Any prior or concurrent exposure to mitoxantrone, alemtuzumab, total lymphoid irradiation 2. Cladribine within 1 year of Screening 3. Any investigational agent within 4 weeks or 5 half-lives of Screening, whichever is longer 4. Other pre-specified Disease-Modifying Therapies be discontinued by the time of pre-conditioning or earlier as described in the protocol * Known malignancy or a history of malignancy * Current symptoms of severe, progressive, or uncontrolled renal, hepatic, hematological, gastrointestinal, pulmonary, psychiatric, cardiac, or concomitant neurological disease, including severe (requiring medical intervention) and uncontrolled infections * Chronic pulmonary disease * Impaired cardiac function or clinically significant cardiac disease * Prior engineered T cell therapy involving permanent gene modification * Prior solid organ (heart, liver, kidney, lung) transplant or hematopoietic stem cell transplant.