Efficacy of biologic therapy in patients with severe occupational and work-related asthma

Severe asthma is characterized by significant prevalence and unfavorable outcomes. Biological therapy with monoclonal antibodies significantly improves the prognosis of T2-phenotype of severe asthma. Features of allergic occupational asthma associated with the properties of industrial allergens determine the need to study its response to biological therapy. The aim of the study was to determine the effectiveness of biological therapy with monoclonal antibodies in patients with occupational or work-related asthma in real clinical practice. Methods. A prospective observational study was conducted involving patients with severe occupational and work-related asthma (n = 49) receiving therapy with monoclonal antibodies (omalizumab (n = 19), reslizumab (n = 3), mepolizumab (n = 8), dupilumab (n = 9), benralizumab (n = 11)). The diagnosis of asthma was confirmed by a positive bronchodilator test. The occupational and work-related nature of the disease was identified by allergy tests or return-to-work test. The primary endpoints were symptom control (ACQ-5 < 0.75) and asthma exacerbations. Statistical analysis was performed using descriptive statistics methods (median and interquartile range, proportions), Mann – Whitney test or χ2 criterion for comparison of independent groups, Wilcoxon test or McNemar criterion for interrelated groups. Cox proportional hazards method was used to search for factors associated with endpoints, Kaplan–Meier method was used for survival analysis. Results. The observation period was 12 – 60 months. Asthma control was achieved in 39 (79.6 %) patients. The following factors were associated with achieving asthma control (relative risk; 95% confidence interval): sensitization to a low-molecular allergen (2.30; 1.84–3.46), a decrease in the forced expiratory volume in 1 second (FEV1) after exercise (0.89; 0.50 – 0.97), and blood eosinophilia (1.02; 1.01 – 1.05). Exacerbations were noted in 49 (100%) subjects before treatment and in 16 (32.7%) during therapy (p = 0.0001). Sensitization to a low-molecular allergen and high baseline blood eosinophilia reduced the likelihood of exacerbations during treatment (0.27; 0.15 – 0.86 and 0.96; 0.92 – 0.99). In the Kaplan–Meier analysis, the probability of symptom control was 90.3% in patients with low-molecular-weight allergen-induced asthma and 61.1% in patients with high-molecular-weight allergens. The survival rate without exacerbations was 72.3% and 37.7%, respectively (p < 0.05). FEV1 increased, and blood eosinophilia decreased. Conclusion. In patients with occupational and work-related asthma, biological therapy prevents exacerbations, increases the probability of symptom control, and improves lung function, primarily in asthma caused by low-molecular-weight allergens.