Alemtuzumab (Lemtrada, Genzyme Corporation), a drug used to treat patients with multiple sclerosis (MS), was found to reverse some of the physical disability caused by the disease, according to new research published online in Neurology. Because it can cause serious adverse effects, alemtuzumab is generally used in patients who have not responded well to other MS drugs; however, in the new study it was used relatively early in the course of MS.
“While many MS drugs slow the progress of disability, there have been little data about the ability of current treatments to help restore function previously lost to MS,” said investigator Gavin Giovannoni, MD, PhD, of Queen Mary University of London.
In the study, patients with relapsing–remitting MS who did not respond well to at least one other MS drug were treated with either alemtuzumab (n = 426) or interferon (IFN) beta-1a (n = 202). The researchers assessed the subjects’ level of disability at the beginning of the study and then every three months for two years.
By the end of the study, approximately 28% of those receiving alemtuzumab had improved by at least one point on a disability test compared with 15% of those receiving IFN. Moreover, the patients treated with alemtuzumab were 2.5 times more likely to improve on an assessment of thinking skills than were those treated with IFN, and were more than twice as likely to show improvement in the ability to move without tremor or ataxia. The researchers adjusted the results to ensure that the improvements were not driven by patients who were recovering from recent relapses.
Giovannoni noted that the benefits of alemtuzumab, if confirmed, need to be considered along with its risks, which include the risk of serious and sometimes fatal autoimmune complications as well as infusion reactions.
“These results are encouraging, but exactly how alemtuzumab may reverse damage–– whether it’s through repairing myelin, creating new nerve synapses, greatly reducing inflammation, or some other mechanism––is yet to be investigated,” Bibiana Bielekova, MD, of the National Institute of Neurological Disorders and Stroke, said in an accompanying editorial. “Longer studies are also needed to see how many people experience, or do not experience, improvement in disability over longer periods of time.”
Alemtuzumab is a recombinant humanized immunoglobulin G1 kappa monoclonal antibody directed against the cell-surface antigen CD52, which is present on T and B lymphocytes as well as on natural killer cells, monocytes, and macrophages. After cell- surface binding to T and B lymphocytes, alemtuzumab causes antibody-dependent cellular cytolysis and complement-mediated lysis. The precise mechanism by which the drug exerts its therapeutic effects in patients with MS is unknown.
Alemtuzumab is approved for the treatment of patients with relapsing–remitting MS, the most common form of the disease, in which symptoms alternate between sudden worsening and remission.
Sources: American Academy of Neurology; October 12, 2016; and Lemtrada Prescribing Information; November 2014.