Oral disease-modifying therapies for relapsing-remitting multiple sclerosis

Purpose. The efficacy and safety of the three oral agents approved by the Food and Drug Administration for the treatment of relapsing-remitting multiple sclerosis (RRMS) are reviewed. Summary. Limitations to parenteral disease-modifying therapies (DMTs) (interferon beta-1a, interferon beta-1b, and glatiramer acetate) for the treatment of RRMS have been addressed by the approval of three oral DMTs: fingolimod, teriflunomide, and dimethyl fumarate. In clinical trials, each of the oral DMTs was superior to placebo in annualized relapse rate, a key indicator of clinical efficacy, and in neuroradiological efficacy. A reduction in disability progression was evident with higher doses of teriflunomide but was not consistently demonstrated with fingolimod or dimethyl fumarate. Each of the oral DMTs demonstrated acceptable safety in clinical trials, with adverse-effect profiles that differ from injectable agents. The safety of both teriflunomide and dimethyl fumarate is supported by long-term use of related agents for other diseases; however, post-marketing surveillance studies are needed to determine the safety of each of the oral DMTs in patients with RRMS. Dimethyl fumarate seems to have the most innocuous safety profile of the three agents. Fingolimod requires first-dose inpatient monitoring due to cardiac safety concerns and multiple laboratory tests prior to initiation of therapy, while teriflunomide has been associated with hepatotoxicity and teratogenicity. Conclusion. With the approval of three oral drugs for RRMS fingolimod, teriflunomide, and dimethyl fumarate the therapeutic strategy for RRMS has evolved to include options that are efficacious and appear to have administration advantages over established parenteral treatments.