Clinical Trial Assessing Temelimab Following Rituximab Treatment in Patients With Relapsing Forms of Multiple Sclerosis

Main Inclusion Criteria: * Current diagnosis of RMS, based on McDonald 2017 criteria * Having received treatment with rituximab, as per local clinical routine for at least 12 months prior to the Screening Visit * Having received their last dose of rituximab not more than 8 weeks and not less than 4 weeks before Randomization (Study Day 1) * Having expanded disability status scale (EDSS) 2.5 - 5.5 inclusive at Screening * Present clinical worsening in one or more neurological domains as assessed by EDSS, ambulatory function as assessed by 6MWT or T25FW, cognitive functioning as assessed by SDMT or increased need of walking aids or pharmacological/procedures for bowel and bladder functions over the last year. Main Exclusion Criteria: * Current diagnosis of primary progressive MS (PPMS) * Any disease other than MS (e.g. myelitis and /or bilateral optic neuritis) that could better explain the patient's signs and symptoms * Usage of any of the following medications prior to the Screening visit: * Any usage of interferon beta, glatiramer acetate, IV immunoglobulin (IVIG), dimethyl fumarate or teriflunomide within 12 months prior to Screening, * Any history of exposure to mitoxantrone, cladribine, alemtuzumab, cyclophosphamide, systemic cytotoxic therapy, total lymphoid irradiation, and/or bone marrow transplantation at any time, * Any usage of natalizumab within 24 months prior to Screening, * Any usage of highly potent immune modulating therapy, such as: ocrelizumab, ofatumumab, fingolimod, siponimod, ozanimod or anti-cytokine therapy, plasmapheresis or azathioprine within 12 months prior to Screening, * Any usage of any experimental treatment if not washed out for ≥ 5 half-lives or ≥ 12 months (whichever is longer), except rituximab which is allowed before the study. * CTCAE Grade 2 or greater lymphopenia * Any major medical or psychiatric disorder that would affect the capacity of the patient to fulfill the requirements of the study * History or presence of serious or acute heart disease such as uncontrolled cardiac dysrhythmia or arrhythmia, uncontrolled angina pectoris, cardiomyopathy, or uncontrolled congestive heart failure (NYHA class 3 or 4) * Any history of cancer with the exceptions of basal cell carcinoma and/or carcinoma in situ of the cervix, and only if successfully treated by complete surgical resection, with documented clean margins and any medically unstable condition as determined by the investigator * Pregnant or breastfeeding women