Systematizing clinical experience in the use of biological treatments in patients with severe bronchial asthma in real world settings with assessment of clinical outcomes and quality of life level is of great interest and value in practical pulmonology.The aim of the BEST study (Real World Evidence of Benralizumab in Eosinophilic Severe AsThma in Russia) was to evaluate effectiveness of benralizumab by control and quality of life associated with respiratory status in patients with eosinophilic phenotype of severe asthma in real clinical practice in Russia.Results. The results obtained through 16 weeks of benralizumab therapy in patients with severe eosinophilic asthma (SEA) were analyzed. All 59 enrolled patients showed significant improvement in the asthma control questionnaire (ACQ-5) score, the quality of life associated with respiratory status according to the St. George Respiratory Questionnaire (SGRQ), and subjective assessments of the well-being of patients and the disease severity (PGIC and PGIS). Treatment with benralizumab contributed to a reduction in the oral glucocorticosteroids intake throughout the study period.Conclusion. In real clinical practice, treatment with benralizumab results in significant improvement in disease control and the quality of life in patients with severe eosinophilic asthma and is characterized by a favorable safety profile.