Recently released results from a phase 2 randomized study in people with active relapsing MS showed that adding the drug daclizumab to standard treatment with interferon beta reduces MS disease activity more than interferon beta alone.
At 51 centers in the United States, Canada, Germany, Italy and Spain, 230 participants taking interferon beta were randomly selected to also receive either high-dose daclizumab (2 milligrams every two weeks), low-dose daclizumab (1 milligram every four weeks) or an inactive placebo. The combined treatments continued for 24 weeks.
MRI scans were taken every four weeks between weeks eight and 24 of the study to assess 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 people 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.
The study was released online Feb. 15 in advance of publication in the April issue of The Lancet Neurology.