Combination therapy in multiple sclerosis.

Over the past decade, multiple sclerosis (MS) has become a treatable neurologic illness. However, given the rather modest benefit of the currently available disease-modifying agents, as well as the challenges associated with performing placebo-controlled, equivalence, and superiority trials, the logic of combining therapies in MS has considerable appeal. Selecting agents for combination requires careful consideration, as the immunomodulating activity of one drug could potentially interfere with the therapeutic effect of another, and certain combinations may be associated with unforeseen adverse effects. Rigorously controlled studies are needed to determine the safest and most effective use of new and existing MS therapies.