Hypersensitivity to siponimod, peanut & soya. Immunodeficiency syndrome. History of progressive multifocal leukoencephalopathy or cryptococcal meningitis. Active malignancies. Patients who in the previous 6 mth had a MI, unstable angina pectoris, stroke/transient ischaemic attack, decompensated heart failure (requiring inpatient treatment) or NYHA class III/IV heart failure. Patients w/ history of 2nd-degree Mobitz type II AV block, 3rd-degree AV block, SA heart block or sick-sinus syndrome, if they do not wear a pacemaker. Patients homozygous for CYP2C9*3 (CYP2C9*3*3) genotype (poor metaboliser). Severe liver impairment (Child-Pugh class C). Women of childbearing potential not using effective contraception. Pregnancy.