Effectiveness of benralizumab in patients with severe asthma

Benralizumab, an interleukin-5 receptor antibody, can be used in patients with severe asthma resistant to existing treatments. This study aimed to clarify the usefulness of benralizumab in clinical practice. We included 24 patients who were administered benralizumab between April 2018 and July 2019. Changes in parameters, including Global Evaluation of Treatment Effectiveness (GETE) scale, ACT, ACQ-5, blood eosinophils, FeNO, and spirometry, after 4 and 24 weeks of administration were examined. Of the 24 patients, 21 completed the treatment for 24 weeks. ACT and ACQ improved in 64% and 76% of the patients, respectively, at 4 weeks, and the effect continued until 24 weeks. The dose was reduced in 10 of 16 patients administered with oral corticosteroid. The mean FEV1 improved at 4 weeks. Moderate positive correlation was found between the improvement rate of FEV1 and eosinophil count before treatment (rho=0.653), and an ROC analysis revealed that a 10% improvement in FEV1 was predicted by the eosinophil count before treatment with the best cut-off value of 200/μl. In patients without increased blood eosinophils, improvement in FEV1 was poor; however, the steroid dose could be reduced in 40% of the patients, and symptom scores also improved. In patients who completed benralizumab for 24 weeks, the frequency of exacerbations was significantly reduced compared with that 24 weeks before administration (19% vs 51%, p=0.006). Benralizumab improved pulmonary function, depending on peripheral blood eosinophil count and symptoms, and reduced the frequency of exacerbation.