RESUMO
There are now several monoclonal antibody (mAb) therapies ("biologics") available to treat severe asthma. Omalizumab is an anti-IgE mAb and is licensed in severe allergic asthma. Current evidence suggests it may decrease exacerbations by augmenting deficient antiviral immune responses in asthma. Like all other biologics, clinical efficacy is greatest in those with elevated T2 biomarkers. Three biologics target the interleukin (IL)-5-eosinophil pathway, including mepolizumab and reslizumab that target IL-5 itself, and benralizumab that targets the IL-5 receptor (IL-5R-α). These drugs all reduce the exacerbation rate in those with raised blood eosinophil counts. Mepolizumab and benralizumab have also demonstrated steroid-sparing efficacy. Reslizumab is the only biologic that is given intravenously rather than by the subcutaneous route. Dupilumab targets the IL-4 receptor and like mepolizumab and benralizumab is effective at reducing exacerbation rate as well as oral corticosteroid requirements. It is also effective for the treatment of nasal polyposis and atopic dermatitis. Tezepelumab is an anti-TSLP (thymic stromal lymphopoietin) mAb that has recently completed phase 3 trials demonstrating significant reductions in exacerbation rate even at lower T2 biomarker thresholds. Many patients with severe asthma qualify for more than one biologic. To date, there are no head-to-head trials to aid physicians in this choice. However, post-hoc analyses have identified certain clinical characteristics that are associated with superior responses to some therapies. The presence of allergic and/or eosinophilic comorbidities, such as atopic dermatitis, nasal polyposis or eosinophilic granulomatosis with polyangiitis, that may additionally benefit by the choice of biologic should also be taken into consideration, as should patient preferences which may include dosing frequency. To date, all biologics have been shown to have excellent safety profiles.
RESUMO
BACKGROUND: Mepolizumab was the first licensed anti-IL5 monoclonal antibody for severe eosinophilic asthma (SEA). To date there are few data to confirm its efficacy in the real-world setting or assessment of baseline characteristics associated with response. RESEARCH QUESTION: How do patients with severe eosinophilic asthma respond to mepolizumab in the real world setting and which characteristics are associated with a super-response to this therapy? STUDY DESIGN AND METHODS: We conducted a retrospective review of all patients who received at least 16 weeks of treatment with mepolizumab (100 mg subcutaneously) for SEA at our regional asthma center in the United Kingdom. Clinical data were collected at each 4-week visit. At 16, 24, and 52 weeks, patients were classified as "responders" or "nonresponders." A response was defined as ≥50% reduction in exacerbations; for patients whose condition requires maintenance oral corticosteroids (mOCS), a response was defined as ≥50% reduction in prednisolone dose. Super responders were defined as exacerbation-free and off mOCS at one year. RESULTS: Ninety-nine patients were included in the analysis. Asthma exacerbations decreased from a baseline of 4.04 ± 2.57 to 1.86 ± 2.17 per year at one year (54% reduction; P < .001). Sixty-eight patients were receiving mOCS at the time of commencing mepolizumab. By one year, the daily median dose fell from 10 mg (interquartile range, 10 to 15) to 0 mg (interquartile range, 0 to 10; P < .001). Fifty-seven percent of them were able to discontinue mOCS; 72.7% (95% CI, 63.0 to 80.7) of the patients were classified as responders, and 28.3% (95% CI, 20.2 to 38.0) of the patients were classified as super responders. Baseline characteristics associated with responder and super responder status included the presence of nasal polyposis (P = .012), lower baseline Asthma Control Questionnaire 6 (P = .006), a lower BMI (P = .014), and, in those patients receiving mOCS, a significantly lower prednisolone dose at baseline (P = .005). At 16 weeks, the one-year responder status was correctly identified in 80.8% patients; by 24 weeks, this status rose to 92.9%. INTERPRETATION: In a real-world SEA cohort, treatment with mepolizumab reduced exacerbation frequency and mOCS requirements. Nasal polyposis, a lower BMI, and a lower maintenance prednisolone requirement at baseline were associated with better outcomes. Twelve-month response was identifiable in >90% of patients by week 24.