Alemtuzumab has been used to treat MS for close to two decades, but it has never been approved for this use. It is given by IV infusion.
The drug not only reduced relapses, but improved disability associated with MS, such as loss of coordination or difficulty walking, in some patients.
Side effects include infusion reactions, infections, and potentially serious autoimmune disorders. Patients taking it must be followed closely.
“In the menu of treatment choices for MS patients, I think alemtuzumab falls into the ‘high-reward, high-risk’ category,” says Alasdair Coles, MD, of Britain’s University of Cambridge, who led one of the newly published studies.
“No other drug has been shown to offer the benefits in terms of disability improvement that this drug shows,” he says. “It comes with problems, but these problems are manageable.”
400,000 MS Patients in U.S.
The National MS Society estimates that about 400,000 people in the United States have been diagnosed with multiple sclerosis, and most (85%) have the relapsing-remitting form of the disease, in which symptoms come and go.
In one of the two newly published studies, University of Cambridge researchers followed 563 previously untreated patients treated with either alemtuzumab or interferon beta.
Two years later, 22% of the alemtuzumab-treated patients had relapsed, compared to 40% of those treated with interferon beta.
In the second study, which included 840 patients whose MS symptoms were not being controlled with other treatments, treatment with alemtuzumab was associated with 35% of patients relapsing over two years, compared to a 51% relapse rate among those treated with interferon beta.
Patients in this study were also less likely to have additional MS-related disabilities after two years when they took alemtuzumab; 13% had disabilities compared to 20% of interferon-treated patients.
1 in 3 Users Develop Autoimmune Disease
In clinical practice, alemtuzumab has most often been used to treat patients who don’t respond to other treatments or are no longer responding to them.
Coles says he believes this is how the drug will continue to be used if it is approved as an MS drug in the U.K. and the U.S.
He adds that about 1 in 3 patients who take the drug for MS develop an autoimmune disorder that affects the thyroid, and about 1 in 100 develop a disorder that involves blood platelets, which are involved in clotting and stopping bleeding.
He says both conditions, while potentially serious, can be easily managed if patients are followed closely.
“Close monitoring is critical because these side effects tend to appear a year or two after treatment, when MS symptoms are often under control and patients want to get on with their lives,” he says.
National MS Society Chief Research Officer Tim Coetzee, PhD, says he does not see this as a big deterrent, since many of the newer drugs for multiple sclerosis also require close monitoring.
“Given the choice between having a treatment that requires aggressive monitoring and not having that treatment at all, I believe that most patients will take the treatment any day of the week,” he says.
Drug’s Cost as MS Treatment in Question
The drug maker Genzyme plans to market alemtuzumab as an MS treatment in the U.S. and Europe, pending approval by government regulators. The drug will not be available to MS patients during the approval process.
In an editorial published with the two studies, editors of the journal Lancet express concerns that the drug will be too expensive for patients and health systems when it is reintroduced as an MS treatment.
“Finding promising treatments such as alemtuzumab is important,” they write. “But so is keeping alemtuzumab accessible and affordable if its early success in these trials proves to be of enduring value.”