Comparing the efficacy of disease-modifying therapies in multiple sclerosis.

Establishing the relative efficacy and safety of the different disease modifying therapies (DMTs) in multiple sclerosis (MS) is critical to the choice of agent that clinicians recommend for individual MS patients. The best evidence for the relative efficacy of the different DMTs comes from head-to-head randomized clinical trials (RCTs). Understanding that outcome-measures with the best established validity are the relapse rate and the actual (not the "confirmed") change in the extended disability status scale (EDSS), we conclude from these head-to-head RCTs that interferon-beta (IFNβ) given subcutaneously multiple times per week (either IFNβ-1b or IFNβ-1a) and glatiramer acetate (GA) are about equivalent in terms of efficacy and that both of these agents, as well as many of the other DMTs, are superior to weekly intramuscular IFNβ-1a. Nevertheless, as ever-newer agents with novel mechanisms of action are brought to the marketplace, such direct head-to-head trials are becoming increasingly impractical, raising the need for alternative methods to draw reasonable inferences from less rigorous clinical data. One possible approach to judging comparative efficacy is to make comparisons across clinical trials using the complimentary analytic methods of calculating both the relative risk/rate and the absolute risk/rate reductions. A consideration and application of this analytic approach is undertaken here. It is only with an understanding of the safety and efficacy of the different agents that we can select, together with the patient, the right agent for the right person.