Relapsing-remitting multiple sclerosis: what is the potential for combination therapy?

Multiple sclerosis is now a treatable disease and several immunomodulating therapies exist, but their clinical efficacy is moderate and treatment failure during the course of the disease is an increasing problem. As agents with different targets are available, the question was raised whether combination of these therapies would: be safe;result in reduction of adverse effects; andprovide synergistic benefit by additive or complementary modes of action. The areas under clinical investigation are general immunosuppression as well as more targeted approaches that interfere with antigen presentation, immune cell transmigration, release of myelinotoxic factors or even axonal damage. Combination of these immunomodulatory drugs seems to be rational and promising. Nevertheless, combination therapies need to be studied in carefully designed clinical trials in selected patient populations in order to demonstrate additive or synergistic effects. This article will summarise current drug combination strategies in relapsing-remitting multiple sclerosis and provide an overview of the initial clinical trials.