The increase in the number of patients with moderate and severe psoriasis, torpid to traditional methods of therapy, necessitates a wider use of genetically engineered biological drugs. The results of recent studies confirm the important role of interleukin-17 (IL-17) in the development of psoriasis. IL-17A is a natural cytokine that is involved in normal inflammation and immune response reactions. IL-17A plays a key role in the pathogenesis of plaque psoriasis and psoriatic arthritis. Inhibition of this cytokine causes a significant improvement in the course of the disease. Secukinumab is an all-human antibody (immunoglobulin G1, IgG1) that selectively binds to and neutralizes the proinflammatory cytokine IL-17A.Secukinumab treatment at a dose of 300 mg for patients with plaque psoriasis provides a more pronounced cleansing of the skin compared with the use of a dose of 150 mg, with a maximum effect at 16 weeks. Secukinumab is effective both in patients who have not previously received therapy with genetically engineered biological drugs and in case of an insufficient response to therapy with inhibitors of tumor necrosis factor alpha. Secukinumab treatment improved the clinical course, quality of life associated with functional status and health status and slowed the progression of disorders of the peripheral joints. The objective of this observational study was to evaluate the efficacy and safety of secukinumab in the treatment of severe forms of psoriasis. The results of clinical observation of two patients treated with secukinumab are presented. As a result of the treatment, the PASI index reached 90% in the patient D., in the patient P. — 94%.