Patients with multiple sclerosis (MS) treated with alemtuzumab show sustained reduction in relapses and disability after five years, according to results reported at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) annual meeting (14 October; Gothenburg, Sweden).
The CAMMS223 study randomised 334 patients with early, active relapsing remitting MS to alemtuzumab (at doses of either 12mg/day or 24mg/day) for up to five days in two or three cycles, or to interferon beta-1a (44mcg, three times/week).
Results after five years of follow-up showed consistently lower annualised relapse rates in patients treated with alemtuzumab (0.11) compared with those randomised to interferon beta-1a (0.35). Only 13% of patients in the alemtuzumab group demonstrated sustained increase in disability, compared with 38% of those taking interferon beta-1a.
“These long-term follow-up data suggest that alemtuzumab may have a significant disease modifying effect in patients with early, active, relapsing-remitting MS,” said Dr Alasdair Coles, senior lecturer, University Cambridge, and lead investigator of the study. He added: “The efficacy after five years is as good as we saw after three years, despite patients being given no more treatment with alemtuzumab, so we are seeing a durable effect.”
Alemtuzumab is an anti-CD52 humanised monoclonal antibody that depletes the lymphocyte pool, effectively clearing the T cells involved in the MS immune response. “After treatment, the new lymphocyte pool is different to that before,” explained Dr Coles.
Further results for patients with highly active relapsing remitting MS in the study (just over half of those taking part) showed the annualised relapse rate was reduced by 81% in those treated with alemtuzumab (0.09) compared to those treated with interferon beta-1a (0.47), after three years’ follow-up. 91% of alemtuzumab-treated patients were free of sustained accumulation of disability, compared to 75% of those in the comparator group. These patients all had highly active disease, with at least two relapses in the year before treatment in the trial, and at least one gadolinium enhancing brain lesions identified by magnetic resonance imaging.
Two phase 3 trials are currently further evaluating alemtuzumab in the treatment of MS, with results expected in 2011.