New treatment strategies in multiple sclerosis

Abstract

Multiple sclerosis is the most common, non-traumatic, disabling neurological disease of young adults, affecting an estimated two million people worldwide. At onset multiple sclerosis can be categorised clinically into relapsing remitting MS (RRMS - 85-90% of patients) or primary progressive MS (PPMS). Relapses typically present sub-acutely over hours to days with neurological symptoms persisting for days to weeks before they gradually dissipate. At first full recovery is the norm, later patients accumulate deficits and ultimately most convert to a secondary progressive phase (SPMS), characterised by deficits that increase in the absence of further relapses. The clinical picture reflects the complex interplay of focal inflammation, demyelination and axonal degeneration occurring within the central nervous system. Since the introduction of a genuine disease-modifying drug, interferon-beta1b in 1993, there has been a growing interest from academia and pharmaceutical companies alike in multiple sclerosis therapy. In part this effort has focused on investigating the "window of therapeutic opportunity" within the natural history of the disease: it is becoming increasingly clear that immunotherapies are not useful in the secondary phase of the disease but may offer long-term benefit if given early in the relapsing-remitting phase. In part, attention is being paid to the details of dosing and administration of the various licensed therapies, but there is also a significant research effort to explore new ways to treat the disease. In this review, we first sketch the landscape of novel therapies in multiple sclerosis and then discuss in detail approaches which are likely to emerge over the next few years.