THURSDAY, Nov. 1, 2012 (HealthDay News) -- The cancer drug alemtuzumab (Campath) reduces the risk of disease relapse in people with multiple sclerosis, two new trials show.
About 85 percent of multiple sclerosis patients start with a form of the disease called relapsing-remitting MS, where symptoms appear sporadically (a relapse) and then either partially or completely fade away. There is no cure for MS, and existing drugs only aim to reduce the symptoms of the disease.
MS occurs when the body's immune system starts to attack the coating of nerve fibers. Alemtuzumab, which is used to treat leukemia and other cancers of the immune system, works by altering the number, proportions and functions of certain types of lymphocytes, which are white blood cells that play a major role in the functioning of the immune system.
In these two clinical trials, British researchers led by Alastair Compston of the University of Cambridge compared alemtuzumab with interferon beta 1a, the most common drug used to treat MS.
The first trial included patients who had never received drug treatment for MS. The relapse rates after two years were 22 percent for those who were given alemtuzumab and 40 percent for those who were given interferon beta 1a.
The second trial included patients who had already been treated with either interferon beta 1a or another MS drug called glatiramer, but had suffered at least one relapse since their initial treatment. The relapse rates were 35 percent for patients who were given alemtuzumab and 51 percent for those who received interferon beta 1a, the investigators found.
The researchers also found that alemtuzumab appeared to reduce the risk of MS-related disability such as the loss of coordination or the ability to walk. Disability rates were 13 percent among those in the alemtuzumab group and 20 percent of those in the interferon beta 1a group. The first trial found no significant difference in disability rates between the two groups of patients.
In both trials, alemtuzumab appeared to increase the risk of certain autoimmune disorders, particularly those affecting the thyroid. These side effects are potentially serious but can be treated, the researchers noted.
The findings were published Oct. 31 in The Lancet.
The findings are "encouraging," according to a journal editorial, which noted that alemtuzumab has been used off-label for many years to treat MS patients.
"These trials have been keenly awaited by clinicians and patients wishing to establish evidence for this practice. . . . However, there is concern that with a license for multiple sclerosis, the cost of alemtuzumab could rise and might become too expensive for many patients [and health systems]," the editorial stated.
"Finding promising treatments such as alemtuzumab is important. But so is keeping alemtuzumab accessible and affordable if its early success in these trials proves to be of enduring value," the editorial concluded.
The U.S. National Institute of Neurological Disorders and Stroke has more about multiple sclerosis.