What we know and do not know about fingolimod: Outline and interpretation of results from the Japanese fingolimod core and extension studies

Multiple sclerosis (MS) is an idiopathic demyelinating disease of the central nervous system (CNS). Autoreactive T cells that recognize undetermined CNS antigens are assumed to mediate the disease. Fingolimod or FTY720, a sphingosine 1-phosphate receptor (S1PR) modulator, downmodulates S1PR on lymphocytes causing retention of circulating lymphocytes in the lymph nodes, including the CNS antigen-autoreactive lymphocytes that invade the CNS. Fingolimod has recently been approved in several countries as a once-daily, oral, disease-modifying drug for relapsing-remitting MS. Recently, the Japanese fingolimod core and extension studies showed the efficacy of fingolimod in terms of brain magnetic resonance imaging criteria and clinical activities in Japanese patients with relapsing MS without longitudinally extensive spinal cord lesions (LESCL). These results were consistent with the effects of fingolimod in Caucasian MS patients. No new safety issues were observed except for severe exacerbations that occurred in four anti-aquaporin-4 antibody-positive cases in whom LESCL were absent at the time of the entry. Thus, fingolimod is regarded as efficacious and safe for Asian MS patients, although Asian neuromyelitis optica cases in the early course of the disease should be excluded from fingolimod treatment.