Efficacy of Rituximab for Remission Maintenance in Patients With Primary Angiitis of the Central Nervous System: an Open-label, Randomized, Controlled Trial Comparing Systematic Rituximab Infusions and Azathioprine

MAINRIPAC is a multicenter, randomized, open-label controlled clinical trial evaluating the efficacy of rituximab versus azathioprine for maintenance of remission in patients with primary angiitis of the central nervous system (PACNS). Patients are randomized 1:1 to receive either rituximab or azathioprine and are followed for 24 months, with regular clinical and brain MRI assessments to evaluate disease relapse and treatment safety.

Inclusion Criteria: * Patient aged 18 years or older * Patients who have documented PACNS diagnosis * Diagnosis is made if the following criteria are met: * History or clinical findings of an acquired neurological deficit of unknown origin after a thorough initial basic assessment; Cerebral angiogram with classic features of vasculitis (alternating areas of smooth-wall segmental narrowing and dilatation of cerebral arteries, arterial occlusions affecting many cerebral vessels, absence of proximal vessel atherosclerosis or other recognized abnormalities), and/or abnormal findings on MRI and CSF profile consistent with PACNS; * Or CNS biopsy sample showing vasculitis; * And no evidence of systemic vasculitis or any other disorder to which the angiographic or pathological features could be secondary (e.g. atherosclerosis, reversible cerebral vasoconstriction syndrome…) * Diagnosis of PACNS validated by the study committee * Patients in remission after induction therapy * Use of an effective method of contraception for female participants of childbearing age. Women of childbearing potential is defined as any female who has experienced menarche and who has not undergone surgical sterilization (hysterectomy or bilateral oophorectomy) or is not postmenopausal. Menopause is defined clinically as 12 months of amenorrhea in a woman over age 45 in the absence of other biological or physiological causes. * Patient able to give written informed consent prior to participation in the study * Affiliation with a mode of social security Exclusion Criteria: * Patients with other vasculitis * Patients with severe cardiac failure * Patients with acute or chronic active infections * Patients with active or recent cancer (\< 5 years) * Pregnant women and lactation * Patients with hypersensitivity to a monoclonal antibody or biologic agent * Patients suspected not to be observant to the proposed treatments * Patients unable to give written informed consent prior to participation in the study * Patients under guardianship, conservatorship, or subject to a court-ordered restraint Administration récente d'un vaccin vivant atténué incompatible avec l'instauration du traitement de l'étude,