ASSESSMENT OF MEPOLIZUMAB EFFICACY IN TREATMENT OF SEVERE, UNCONTROLLED EOSINOPHILIC ASTHMA ACCORDING TO THE BASELINE BLOOD EOSINOPHIL COUNT: EXPERIENCE OF KAUNO KLINIKOS SEVERE ASTHMA CENTRE

Abstract

Mepolizumab is a biological agent for add-on maintenance therapy in treating severe eosinophilic asthma. Numerous randomized clinical trials demonstrated the efficacy of this drug. However, many questions remain unanswered, particularly regarding the natural course of severe asthma (SA) as well as the predictive factors of successful SA treatment.
Objective. Based on baseline blood eosinophil count evaluate the efficacy of mepolizumab as an add-on treatment for severe uncontrolled eosinophilic asthma (a study of the Lithuanian University of Health Sciences Kauno klinikos SA Center). Methods. A retrospective data analysis of 34 patients with severe uncontrolled eosinophilic asthma treated with mepolizumab was performed. All subjects were divided into two groups based on baseline blood eosinophil count (9 patients with eosinophil count ≤0.30×109/l and 25 patients with eosinophil count >0.30×109/l). The efficacy of mepolizumab was assessed by analyzing oral corticosteroid use (OCS), asthma control test (ACT), asthma exacerbation rate, and lung function parameters at 4 and 12 months after initiation of treatment. The data were also compared between the groups. Results. Treatment with mepolizumab improved asthma control yet after 4th month of treatment compared to the baseline in both groups (group ≤0.30×109/l ACT score 11.1±3.8 vs 15.3±4.5, p=0.016; group >0.30×109/l 11.8±4.5 vs 18.4±5.3, p=0.001). Asthma control remained improved after 12 months (comparing 12 months’ data to the baseline ACT scores) in both groups too (group ≤0.30×109/l 11.1±3.8 vs
17.1±4.6, p=0.007; group >0.30×109/l – 11.8±4.5 vs 19.5±3.1, p=0.001). Moreover, this treatment enabled to decrease OCS dose after 4th month (16.0±10.2 vs 5.5±9.3 mg/d, p=0.045) and 12th month (16.0±10.2 vs. 0.5±1.6 mg/d, p=0.007) for the patients with a higher baseline eosinophil count (>0.3×109/l). The lung function also significantly improved after 12 months (FEV1 1.86±1.00 vs 2.31±1.00 l, p=0.017) for the patients with a higher baseline eosinophil count (>0.3×109/l). Furthermore, reduced asthma exacerbation was also observed (group ≤0.30×109/l 3.2±0.8 vs 0.6±1.0, p=0.011; group >0.30×109/l – 3.8±2.7 vs 0.6±1.4, p=0.001) in both groups after one year. Conclusions. The experience of Kauno klinikos SA centre showed that 12-months severe uncontrolled eosinophilic asthma treatment with mepolizumab significantly improves lung function and decreases OCS dose for the patients with a higher baseline eosinophil count (>0.3×109/l).