Merck AG

Prolonged anti CD20 therapy for the treatment of active multiple sclerosis leading to continuous B cell depletion is associated with hypogammaglobulinemia predisposing to a potentially increased risk of serious infections, particularly in the more disabled and aged patients. No data have been published on the sequential use of anti CD20 therapies and cladribine, that is thought to act as an immune reconstitution agent. his study aims at investigating IgG and IgM serum concentration changes at 6 and 12 months after switching to cladribine in patients previously treated with anti CD20 therapies (ie, ocrelizumab ≥1.8 gr or rituximab 3.0 gr) for ≥18 months, as compared to continued anti CD20 therapies.