[Siponimod (BAF312): General Characteristics and Clinical Implications of Pharmacogenomic Dosage in the Treatment of Active Secondary Progressive Multiple Sclerosis].

Siponimod is a selective immunosuppressive medication, developed as the first oral therapy for active secondary progressive multiple sclerosis. This medication acts by modulating the sphingosine 1 phosphate (S1P) receptor, as an antagonist of S1P1 and S1P5, thus preventing the egress of lymphocytes from lymph nodes and preventing inflammatory processes in the Central Nervous System that trigger demyelination. There is extensive scientific knowledge regarding the administration of the medication to patients, which will depend on their pharmacogenetic characteristics. Therefore, the FDA strongly recommends conducting a genotyping study of the enzyme that metabolizes siponimod, CYP2C9, whose genetic variants *2 and *3 classify patients as poor, extensive, or rapid metabolizers. Siponimod is completely contraindicated for patients who are homozygous for CYP2C9*3. Additionally, before prescribing it, an electrocardiogram, assessments of antibody status, ophthalmic evaluation, varicella vaccination status, and peripheral lymphocyte count should be conducted, as the medication's effect is dose-dependent. Therefore, a titration process is carried out starting from 0.25mg up to 2 mg. The pharmacotherapeutic protocol of siponimod is a reliable reflection of the utility of pharmacogenetics in personalized medicine.