Drug Treatment of Clinically Isolated Syndrome

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that leads to inflammation, demyelination and ultimately axonal degeneration. In most cases, it is preceded by its precursor, clinically isolated syndrome (CIS) with conversion rates to clinically definite MS (CDMS) of roughly 20-75%. Neurologists are therefore faced with the challenge of initiating a disease-modifying therapy (DMT) as early as possible to favorably influence the course of the disease. During the past 20 years, a multitude of drugs have been incorporated into our therapeutic armamentarium for MS and CIS. Choosing the right drug for an individual patient is complex and should be based not only on the drug's overall efficacy to prevent disease progression but also its specific adverse reaction profile, the severity of individual disease courses and, finally, patient compliance in order to adequately weigh associated risks and benefits. Here, we review the available data on the efficacy, safety and tolerability of DMTs tested for CIS and discuss their value regarding a delay of progression to CDMS.