NEW ORLEANS—Among treatment-naïve patients with relapsing–remitting multiple sclerosis (MS), alemtuzumab reduced the relapse rate by 55%, compared with interferon beta-1a, said Alasdair Coles, PhD, member of the Department of Clinical Neurosciences at Cambridge University in the United Kingdom, at the 64th Annual Meeting of the American Academy of Neurology. Eight percent of patients receiving alemtuzumab experienced sustained accumulation of disability, compared with 11% of patients receiving Rebif, but this difference was not statistically significant, according to findings from the Comparison of Alemtuzumab and Rebif Efficacy in Multiple Sclerosis I (CARE-MS I) study.
“Perhaps most significantly,” the study provided evidence for alemtuzumab’s superiority “on reducing the rate of tissue loss, as measured by MRI, compared to the active drug Rebif,” said Dr. Coles. Alemtuzumab also had a superior effect on measures of neurologic impairment and on MRI measures of new inflammatory lesions, compared with that of Rebif.
In the two-year phase III trial, Dr. Coles and his colleagues randomized 581 treatment-naïve patients from 98 centers in 16 countries to alemtuzumab or interferon beta-1a to compare the clinical efficacy and safety outcomes of the two drugs. All patients had highly active relapsing–remitting MS but had not yet accumulated disability. Participants’ mean age was 33, and their mean Expanded Disability Status Scale (EDSS) score was 2. EDSS raters were blinded to treatment, and all relapses were adjudicated by an independent end point panel.
The annualized relapse rate was 0.18 for patients receiving alemtuzumab, compared with 0.39 for patients receiving interferon beta-1a. Approximately 78% of patients receiving alemtuzumab were relapse-free, compared with nearly 59% of patients receiving interferon beta-1a.
Alemtuzumab was associated with more adverse events than was interferon beta-1a, including infusion-associated symptoms such as headache, pyrexia, and rash. Premedication and further treatment with antihistamines and antipyretics ameliorated these symptoms.
“As we have come to expect, there was an excess of thyroid autoimmunities following alemtuzumab,” said Dr. Coles. In addition, three cases of idiopathic thrombocytopenic purpura occurred in the alemtuzumab arm, and one case occurred in the interferon beta-1a arm. The study’s risk-minimization program identified all cases, and appropriate treatment restored patients’ platelet counts and prevented sequelae.
—Erik Greb