NEW ORLEANS—Most patients with relapsing-remitting multiple sclerosis (MS) with highly active disease remain free of new MRI activity for six years after receiving alemtuzumab, according to research presented at the 31st Annual Meeting of the Consortium of MS Centers. The durable effects may result from the distinct pattern of lymphocyte repopulation following treatment with alemtuzumab, which may lead to a rebalancing of the immune system, said Anthony Traboulsee, MD, Associate Professor of Neurology at the University of British Columbia in Vancouver. Additional mechanistic studies are needed to establish this hypothesis, the authors said.
Anthony Traboulsee, MD
To evaluate six-year MRI and brain volume loss outcomes in a subset of patient with highly active disease at baseline who were treated with alemtuzumab, Dr. Traboulsee and colleagues analyzed data from the CARE-MS I trial. In that trial, researchers randomized patients with active relapsing-remitting MS who were drug-naïve at baseline to alemtuzumab or interferon beta-1a. After two years, patients who received alemtuzumab had improved clinical and MRI outcomes, including brain loss volume, compared with patients who received interferon beta-1a. In addition, significantly more of these patients had no evidence of disease activity, compared with patients treated with interferon beta1-a.
In an extension study, patients could receive additional treatment with alemtuzumab (12 mg/day on three consecutive days one year or more after the most recent course) as needed for relapse or radiologic activity. During the extension, patients also could receive treatment with other licensed disease-modifying therapies at an investigator’s discretion. Retreatment criteria included one or more relapse, two or more new or enlarging T2 hyperintense lesions, or new gadolinium-enhancing T1 brain or spinal cord lesions on MRI. Researchers defined highly active disease as two or more relapses a year prior to randomization and one or more gadolinium-enhancing T1 lesion at core study baseline.
The researchers obtained MRI scans at baseline and yearly thereafter. Experts masked to patients’ original treatment group assignment analyzed the MRI scans. Investigators assessed the proportion of patients free of MRI disease activity (ie, no new or enlarging T2 hyperintense lesions or new gadolinium-enhancing T1 lesions) and the proportion of patients free of new non-enhancing T1 lesions. Brain volume loss was derived by brain parenchymal fraction change.
Of 376 patients who received alemtuzumab in the CARE-MS I trial, 105 met the criteria for highly active disease at core study baseline. Of these 105 patients, 99 remained in the study through Year 6. Through six years, 63% of patients did not receive additional treatment with alemtuzumab or another disease-modifying therapy. In each year through Year 6, a majority of patients were free of MRI disease activity (61 % at Year 6), free of new gadolinium-enhancing T1 lesions (83% at Year 6), and free of new or enlarging T2 hyperintense lesions (62% at Year 6). The investigators also observed that annually in Years 2 through 6, high proportions of patients had no new non-enhancing T1 hypointense lesions.
“These findings, along with long-term clinical efficacy, suggest that alemtuzumab may provide a unique treatment approach for relapsing-remitting MS patients with highly active disease, offering durable efficacy in the absence of continuous treatment,” said Dr. Traboulsee and colleagues.