Population structure and HLA DRB1 1501 in the response of subjects with multiple sclerosis to first-line treatments.

Using retrospectively collected outcome data for treatment naïve subjects treated with either glatiramer acetate (GA) (n=332) or interferon beta (IFN β) (n=424), we replicated the lack of a significant difference in efficacy between these treatments. Further, for both treatments, we observed a decline in the hazard of a relapse over time, which may suggest the existence of subsets of subjects with differential responses to each treatment. The HLA DRB1*1501 allele explained some of this variation in event-free survival while on GA, and we found suggestive evidence that an IRF8 polymorphism influences event-free survival in IFN β treated subjects.