Intrathecal Rituximab in Progressive Multiple Sclerosis

• Background : Multiple sclerosis (MS) is the most frequent inflammatory disorder leading to impairment in young people. Although many drugs are now available to treat the early relapsing-remitting phase of MS (RR-MS), impairment is mostly linked to the secondary progressive phase of MS. Since no treatment proved to efficiently prevent or cure this progressive phase, treating this phase remains challenging. In fact, progressive phase is associated with a fence-ringed intrathecal compartmentalization of inflammation, leading to the unavailability of most immunosuppressive drugs. As a consequence, investigators here propose to shift the therapeutic paradigm in MS to a new paradigm based on intrathecal infusion of monoclonal antibodies (mAb) aimed at eradicate intrathecal inflammation. Rituximab is a mAb targeting CD20+ B-lymphocytes. Positive results in RR-MS were obtained after blood infusion of rituximab, but results were negative in progressive MS, probably due to the very low penetration of the blood brain barrier. Since intrathecal rituximab is already used in central nervous system (CNS) lymphomas, investigators propose to use it this way in progressive MS.

• Detailed description : An optimal dosage of rituximab for intrathecal infusion was choose using data already obtained in CNS lymphoma, acknowledging that 20mg offers the higher dosage with good tolerance profile. In order to isolate rituximab effect, a control group is treated by steroids since steroids are required before rituximab infusion. Moreover, B-lymphocytes depletion in CSF will probably be transient, as it is when rituximab is infused in blood. Assuming that CSF B-cells repopulation may be facilitated by peripheral B-cells, a group was assigned to receive also blood infusion of rituximab. CSF will be examined at multiple time points to assess the time frame of biological effect obtained in CSF.

Three groups of 4 patients are treated at day 0 :

1. Control group : receive a single pulse of intravenous (IV) methylprednisolone (120mg) ;
2. Rituximab intrathecal (IT) group : receive a single intrathecal infusion of rituximab (with IV methylprednisolone 120mg to avoid side effect) ;
3. Rituximab IT + IV group : receive same as previous and IV rituximab (375mg/m2) the same day.

CSF and blood will be drawn for study at day 0 (before treatment), day 4, day 21 and day 180. B- lymphocytes monitoring in blood will be also be done at day 365. A detailed clinical monitoring (walking time, nine hole peg test, Expanded Disability Status Score (EDSS), Symbol Digit Modalities Test (SDMT), fatigue intensity scale) will be done at each time point from day 0 to 365, assessing tolerance and clinical effect. MRI will be done at screening, months 6 and 12.