BACKGROUND: Alemtuzumab (CD52-specific humanized monoclonal antibody) was found 
to be an effective therapy for treatment-naive patients with relapsing-remitting 
multiple sclerosis.
OBJECTIVE: Evaluate alemtuzumab's effects in patients with treatment-refractory 
relapsing-remitting multiple sclerosis.
METHODS: Forty-five relapsing-remitting multiple sclerosis patients who 
experienced ≥2 relapses during 2 years prior to the study entry whilst receiving 
interferon therapy were administered 24 mg i.v. alemtuzumab/day for 5 days at 
baseline and 3 days 12 months later. Patients received premedication with 1 g 
i.v. methylprednisolone on days 1-3 at both times.
RESULTS: After 2-year follow-up, the annualized relapse rate was reduced by 94% 
compared to pre-treatment levels, from 1.6 (2 years prior to treatment) to 0.17 
for the 2 years following (P<0.0001). Moreover, 86% of patients showed stable or 
improved scores on the Expanded Disability Status Scale, and only 1 experienced 
an increase in disability lasting ≥6 months. The majority (70-88%) showed stable 
or improved leg, arm and cognitive function as measured by the Multiple 
Sclerosis Functional Composite. Serious adverse events observed in single 
patients were transient neutropenia and pneumonia, pulmonary emboli and deep 
vein thrombosis. Five patients developed clinical thyroid disorders but no 
opportunistic infections or cases of immune thrombocytopenic purpura were 
observed.
CONCLUSIONS: Alemtuzumab effectively reduced relapse rates and improved clinical 
scores in patients with active relapsing-remitting multiple sclerosis not 
controlled by interferon therapy.