A new study has revealed that patients with relapsing multiple sclerosis who combine standard treatment with doses of a humanized monoclonal antibody called daclizumab might develop fewer new or enlarged brain lesions than if they use the standard treatment alone.
Multiple sclerosis (MS) is a debilitating disease in which the body's immune system attacks the fatty substance that surrounds and protects the nerve fibers in the brain and spinal cord.
The resulting damage interferes with the transmission of nerve signals between the brain and spinal cord and other parts of the body, producing a variety of symptoms including problems with balance, coordination, vision, and even mental function.
Approximately 85 percent of multiple sclerosis patients are initially diagnosed with relapsing MS, in which clearly-defined attacks of worsening neurologic function are followed by partial or complete recovery periods during which no disease progression occurs.
"Previous research has shown that treatment with daclizumab reduced multiple sclerosis disease activity," says John W. Rose, professor of neurology at the University of Utah School of Medicine, Neurovirology Research Laboratory, Veterans Affairs Salt Lake City Health Care System and the University of Utah, an author on the study.
"Our work in the CHOICE trial shows that daclizumab significantly reduces MS lesion formation in people with active relapsing disease," he added.
Monoclonal antibodies are immune system proteins that preferentially bind to specific target cells, triggering the immune system to attack those cells.
Daclizumab is a monoclonal antibody specific for CD25, a protein that is expressed on activated T cells, and binding of daclizumab to CD25 results in selective inhibition of these activated T cells.
Daclizumab treatment has been studied in patients with human autoimmune conditions, such as MS, that are characterized by abnormal T-cell responses.
Rose and his colleagues performed a randomized, double-blind, placebo-controlled study at 51 centers in the U.S., Canada, Germany, Italy, and Spain.
They recruited 230 patients with relapsing MS who were taking interferon beta and randomly assigned them to receive add-on treatment with high-dose daclizumab, low-dose daclizumab, or placebo.
The primary objective of the study was to assess whether daclizumab affected MS disease activity by measuring the total number of new or enlarged lesions in the brain during 24 weeks of treatment.
In addition to finding that add-on treatment with high-dose daclizumab resulted in a significantly lower number of new or enlarged MS lesions, the researchers found that patients treated with either high- or low-dose daclizumab had a seven to eight times higher number of immune cells called CD56bright natural killer cells (NK Cells).
Previous research has shown that untreated MS patients have lower numbers of these NK cells than healthy individuals.
This new study was published online Feb. 16, 2010, and in the March edition of the Lancet Neurology.