Multiple sclerosis treatment faces tremendous changes as a result of the approval of new medications. The new medications have differing safety considerations and risks after long-term treatment, which are important for treating physicians to optimize and individualize
multiple sclerosis care. Since the approval of the first
multiple sclerosis capsule,
fingolimod, the armamentarium of
multiple sclerosis therapy has grown with the orally available medications
dimethyl fumarate and
teriflunomide.
Fingolimod is mainly associated with cardiac side effects,
dimethyl fumarate with bowel symptoms. Several reports about
progressive multifocal leukoencephalopathy as a result of
dimethyl fumarate or
fingolimod therapy raised the awareness of fatal
opportunistic infections.
Alemtuzumab, a CD52-depleting antibody, is highly effective in reducing relapses but leads to secondary immunity with mainly thyroid disorders in about 30% of patients. Development of secondary B-cell-mediated disease might also be a risk of this antibody. The follow-up drug of the B-cell-depleting antibody
rituximab,
ocrelizumab, is mainly associated with infusion-related reactions; long-term data are scarce. The medication
daclizumab high yield process, acting via the activation of CD56bright natural killer cells, can induce the elevation of liver function
enzymes, but also
fulminant liver failure has been reported. Therefore,
daclizumab has been retracted from the market. Long-term data on the
purine nucleoside cladribine in MS
therapy, recently authorized in the European Union, have been acquired during the long-term follow-up of the
cladribine studies. The small molecule
laquinimod is currently under development. We review data of clinical trials and their extensions regarding long-term efficacy and side effects, which might be associated with long-term treatment.