Multiple sclerosis is a chronic inflammatory disease of the CNS. Secondary progressive MS is the second most common form of MS worldwide and symptomatic treatment is currently the only available option in the Czech Republic. Neurodegeneration and less inflammatory processes are the main pathophysiological processes underlying the transition to the secondary progressive phase of MS. Because of clinical diagnostic obstacles, the diagnosis of secondary progressive MS is often postponed by 3 years. Diagnostic criteria based on the data from MSBase registry enable the elimination of this diagnostic gap. Siponimod is the first oral drug for the treatment of secondary progressive MS with clinical or MRI activity reducing the disability progression or selected MRI parameters. The efficacy and safety of siponimod were tested in the phase III clinical trial EXPAND. The most suitable criteria for treatment with siponimod and its safety profile including possibilities in the case of treatment failure are under scrutiny of the scientific neurological society in the Czech Republic.