A Phase 1 Open-label Trial of Intrathecal Rituximab for Progressive Multiple Sclerosis Patients With Magnetic Resonance Imaging Evidence of Leptomeningeal Enhancement

Multiple sclerosis (MS) is a chronic inflammatory disorder affecting the central nervous system that is characterized pathologically by focal demyelinating lesions in the brain parenchyma. Meningeal inflammation in MS was first noted in 2004. Ectopic lymphoid follicles were described in the meninges of patients with secondary progressive MS (SPMS) and were thought to correlate with cortical lesions and atrophy (a surrogate marker for disability). Subsequently, inflammation in the meninges has been described in primary progressive MS (PPMS) as well as early relapsing MS.

The ectopic lymphoid follicles are composed of B-cells, T follicular helper cells and follicular dendritic cells. Rituximab is a monoclonal antibody against CD-20 (a B-cell marker) that is FDA approved for the treatment of various lymphomas. It has been shown to be effective when given intravenously in trials of Relapsing-Remitting Multiple Sclerosis (RRMS). However, the cerebrospinal fluid (CSF) penetrance of rituximab is minimal, such that CSF levels are < 1% of serum levels after the administration of intravenous (IV) rituximab. Indeed, IV rituximab failed to significantly slow disability in a clinical trial in progressive MS. Intrathecal (IT) rituximab administration has been used in CNS lymphoma to achieve greater CSF concentrations of rituximab. In MS, IT administration of rituximab could lead to higher CSF rituximab levels resulting in the disruption of meningeal ectopic lymphoid follicles, ultimately reducing cortical lesions and possibly disease progression.

A recently described finding is the presence of enhancing meningeal lesions on post-contrast FLAIR imaging in MS patients. These could possibly represent ectopic lymphoid follicles. This finding could serve as a biomarker to identify patients with ectopic meningeal lymphoid follicles who might be most likely to derive benefit from IT rituximab therapy.

The investigators hypothesize that IT rituximab therapy in patients with progressive forms of MS could disrupt ectopic lymphoid follicles in the meninges and thus slow progression of the disease, which is particularly important because there exist no FDA-approved therapies for progressive MS. The investigators hypothesize that using post-contrast FLAIR imaging to identify those with enhancing meningeal lesions will provide a biomarker to select patients who might be most likely to respond to IT rituximab and to use these lesions to monitor therapeutic response.

The primary aim of this study is to assess the safety of intrathecal administration of rituximab in patients with progressive MS. The secondary aims are to evaluate if IT rituximab leads to a decrease in the quantity of meningeal lesions on post-contrast FLAIR imaging or to changes in biomarkers of inflammatory activity or neuronal injury in the CSF.