Short-term B-cell Depletion in Relapsing Multiple Sclerosis

Study Summary

Several disease-modifying therapies (DMTs) have been shown to be effective in reducing the disease activity in patients with relapsing forms of multiple sclerosis (MS) but these treatments, often need to be used continuously for an unknown duration, rendering the long-term use extremely expensive. In addition, chronic administration of DMTs is often associated with undesirable side effects. Among these medications, B-cell depleting monoclonal antibodies might have the properties of an ideal group of medications: i) B-cell depleting antibodies have proven to be extremely potent in reducing or stopping the disease activity in relapsing MS, ii) B-cell depleting antibodies are very safe if used for a short period and use for a short duration may stop the inflammatory disease activity over long term, although current clinical practice and protocols are based on continuing B-cell depletion for an unknown period of time. Indeed, early phase clinical trials of rituximab and ocrelizumab suggested that a short course treatment with B-cell depleting antibodies can have long term effects and disease activity will not return even long after B-cell repopulation in the blood. This long-term effect might be related to the specific pattern of B-cell tolerance defect in patients with MS and the potential of its normalization with B-cell depleting antibodies. By analyzing the reactivity of recombinant antibodies expressed from single B-cells, the investigators' collaborators have demonstrated that the pattern of B-cell tolerance defect is different in people with MS who only display an impaired removal of developing autoreactive B-cells in the periphery while central B-cell tolerance in the bone marrow is functional in most patients. In contrast, patients with rheumatoid arthritis (RA), type-1 diabetes (T1D) or Sjögren's syndrome (SS) show defective central and peripheral B-cell tolerance checkpoints. As a consequence, while anti-B-cell therapy does not correct defective early B-cell

Primary Outcome

Number of patients with a return of disease activity after the third month post-first-infusion, objectively demonstrated by development of new T2 hyperintense lesions or Gd-enhancing lesions on the MRI or a clinical relapse that is confirmed with an objective change in the neurological examination.

Interventions

• DRUG Ocrelizumab