S1PR1 and relapsing-remitting multiple sclerosis: Multiple sclerosis (MS) is the most common chronic, immune‐mediated, and neurodegenerative disease in young adults.[1,2] Fingolimod (Gilenya®, Novartis Pharma AG), a sphingosine 1-phosphate receptor modulator, was the first oral drug approved in Spain for treating remitting-relapsing multiple sclerosis (RRMS) patients.[3] Fingolimod acts as a functional antagonist of the sphingosine-1-phosphate type 1 receptor, inducing receptor internalization and rendering T and B cells insensitive to the egress signals from secondary lymphoid tissues.