Asthma is a chronic inflammatory disease of the airways that affects approximately 300 million people globally with about 5-10% of asthmatics being severe asthma.¹ Severe asthma typically requires treatment with high-dose inhaled corticosteroid (ICS) plus a second controller and/or systemic corticosteroids for controlled managment.¹ However, patients with severe asthma usually suffer from a series of associated comorbidities that require additional biologics to control the worsened symptoms.¹ As studies about biologics treating asthma with comorbidities are limited, a recently published study has investigated the real-world effectiveness of a biologic, mepolizumab, in the management of patients with severe asthma as stratified by common overlapping comorbid conditions.²

Severe asthma is characterized by poor symptom control, airflow limitation and frequent exacerbations despite the use of ICS and a long-acting β2-agonist (LABA) or oral corticosteroids (OCS).³ The disease is frequently associated with atopic, respiratory and other comorbidities including obesity, anxiety and depression which compound on top of existing asthma symptoms and present challenges for asthma management, leading to increased healthcare resource utilization (HCRU).² Consequently, careful management of these comorbidities could provide clinical benefit for asthma patients.²

Mepolizumab is a targeted, humanized anti-interleukin (IL)-5 monoclonal antibody that inhibits IL-5 from binding to its receptors on eosinophils and selectively inhibits eosinophilic inflammation without complete eosinophil count depletion.⁴ In clinical practice, several studies had shown the benefits of mepolizumab in a general population of patients with severe eosinophilic asthma, but the real-world efficacy of mepolizumab in asthmatics with specific comorbidities remained undetermined.² Against this background, a retrospective analysis was conducted to describe the real-world effectiveness of mepolizumab and the associated HCRU in patients with severe asthma as stratified by common overlapping comorbid conditions.²

The United States-based retrospective analysis studied the patient data from the MarketScan Commercial and Medicare Supplemental Database in 2014-2018.² Eligible asthmatics were at least 12-years-old, received at least two administrations of mepolizumab within 180 days, and had at least one claim (excluding claims for diagnostic tests) with a diagnosis code for at least one of the seven comorbidities (atopic disease, nasal polyps, chronic sinusitis, obesity, respiratory infections, chronic obstructive pulmonary disease [COPD], and depression or anxiety) at baseline.² These comorbidities were used to divide patients into seven non-mutually exclusive subgroups.² Outcomes included asthma exacerbations and exacerbation-related HCRU during the 12-month baseline and follow-up periods.²

A total of 639 patients were included in the study, with atopic diseases (73.2%), respiratory infections (55.6%) and chronic sinusitis (45.1%) as the most common comorbidities.² Across the seven comorbidity subgroups, significant decreases in exacerbations by 38-55% and exacerbations requiring hospitalization by 57-83% (both p<0.05) were observed during the follow-up when compared to the baseline period, except for exacerbations requiring hospitalization in the nasal polyps subgroup due to the small subgroup sample size.² In addition, significant reduction in the mean number of OCS claims by 29-38% was observed during follow-up when compared with baseline periods (p<0.001) with 39-47% of patients experienced at least 50% decrease in their OCS dose over 12 months.² In respect to exacerbation-related HCRU, the mean numbers of exacerbation-related inpatient admissions and emergency department visits were significantly reduced by at least 50% during the follow-up versus baseline periods in all comorbidity subgroups except the nasal polyps subgroup (p<0.05).² Similarly, significant decreasing trends were also observed in the mean numbers of exacerbation-related outpatient office visits and outpatient pharmacy claims (p<0.05).² Of note, in most subgroups, reductions in the mean number of exacerbations and OCS use during follow-up versus baseline periods were most obvious in patients with at least 10 mepolizumab administrations during the follow-up period.²

These results suggested that patients suffering from severe asthma gained real-world clinical benefits with mepolizumab irrespective of the presence of common comorbidities including airway diseases, obesity and mood disorders.² A significant reduction in exacerbation rate, OCS use and exacerbation-related HCRU was also observed with mepolizumab treatment.² The treatment benefits were clearer in patients with more mepolizumab administrations during the 12-month follow-up period, which further demonstrated the efficacy of mepolizumab despite the complexities of asthmatic comorbidities.²