Multiple sclerosis (MS) is a presumed autoimmune disorder of the central nervous 
system, resulting in inflammatory demyelination and axonal and neuronal injury. 
New diagnostic criteria that incorporate magnetic resonance imaging have 
resulted in earlier and more accurate diagnosis of MS. Several immunomodulatory 
and immunosuppressive therapeutic agents are available for relapsing forms of 
MS, which allow individualized treatment based upon the benefits and risks. 
Disease-modifying therapies introduced in the 1990s, the beta-interferons and 
glatiramer acetate, have an established track record of efficacy and safety, 
although they require administration via injection. More recently, monoclonal 
antibodies have been engineered to act through specific mechanisms such as 
blocking alpha-4 integrin interactions (natalizumab) or lysing cells bearing 
specific markers, for example CD52 (alemtuzumab) or CD20 (ocrelizumab and 
ofatumumab). These agents can be highly efficacious, but sometimes have serious 
potential complications (natalizumab is associated with progressive multifocal 
leukoencephalopathy; alemtuzumab is associated with the development of new 
autoimmune disorders). Three new oral therapies (fingolimod, teriflunomide and 
dimethyl fumarate, approved for MS treatment from 2010 onwards) provide 
efficacy, tolerability and convenience; however, as yet, there are no long-term 
postmarketing efficacy and safety data in a general MS population. Because of 
this lack of long-term data, in some cases, therapy is currently initiated with 
the older, safer injectable medications, but patients are monitored closely with 
the plan to switch therapies if there is any indication of a suboptimal response 
or intolerance or lack of adherence to the initial therapy. For patients with MS 
who present with highly inflammatory and potentially aggressive disease, the 
benefit-to-risk ratio may support initiating therapy using a drug with greater 
potential efficacy despite greater risks (e.g. fingolimod or natalizumab if JC 
virus antibody-negative). The aim of this review is to discuss the clinical 
benefits, mechanisms of action, safety profiles and monitoring strategies of 
current MS disease-modifying therapies in clinical practice and of those 
expected to enter the market in the near future.