Added Drug Aids MS Treatment

TUESDAY Feb. 16, 2010 -- Adding the drug daclizumab to standard treatment with interferon beta may reduce multiple sclerosis disease activity more than interferon beta alone, a new study reports.

Previous non-randomized studies found that daclizumab -- a humanized monoclonal antibody -- reduced MS disease activity.

This new phase 2 study at 51 centers in the United States, Canada, Germany, Italy and Spain included 230 patients with active relapsing MS who were taking interferon beta. They were randomly selected to also receive either high-dose daclizumab (2 milligrams/kilogram every two weeks), low-dose daclizumab (1 milligram/kilogram every four weeks) or an inactive placebo. The combined treatments continued for 24 weeks.

MRI scans of the patients' brains were taken every four weeks between weeks 8 and 24 of the study in order to determine the number of new or enlarged gadolinium contrast-enhancing lesions, which indicate MS disease activity.

By the end of the study, the adjusted mean number of new or enlarged gadolinium contrast-enhancing lesions was 1.32 in the high-dose group (75 patients), 3.58 in the low-dose group (78 patients) and 4.75 in the placebo group (77 patients).

Levels of CD56bright natural killer cells were seven to eight times higher in patients taking daclizumab than in those taking the placebo.

"This study provides confirmatory data that daclizumab treatment causes an expansion of CD56bright natural killer cells and adds support to the theory that expansion of CD56bright natural killer cells might mediate some of the effects of daclizumab on reducing multiple sclerosis lesion activity. In addition to the results of previous trials of daclizumab in multiple sclerosis, several lines of evidence have suggested a potential immunoregulatory function for CD56bright natural killer cells: they are expanded during conditions of natural immune tolerance, for example, pregnancy," the researchers from the Neurovirology Research Laboratory at the VA Medical Center in Salt Lake City, and the University of Utah, reported in a news release.

"This randomized controlled trial indicates that daclizumab can reduce new lesion formation in relapsing multiple sclerosis compared with interferon-beta alone," the researchers concluded. "Multiple sclerosis treatments that have the potential to improve in risk-benefit ratios when compared with available treatments are needed; thus, additional studies to define the long-term clinical risks and benefits of daclizumab are warranted."

The study was released online Feb. 15 in advance of publication in the April issue of The Lancet Neurology.

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about multiple sclerosis.

Posted: February 2010


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