BACKGROUND: Exacerbations of asthma are associated with substantial morbidity and mortality and with considerable use of health care resources. Preventing exacerbations remains an important goal of therapy. There is evidence that eosinophilic inflammation of the airway is associated with the risk of exacerbations. METHODS: We conducted a randomized, double-blind, placebo-controlled, parallel-group study of 61 subjects who had refractory eosinophilic asthma and a history of recurrent severe exacerbations. Subjects received infusions of either mepolizumab, an anti-interleukin-5 monoclonal antibody (29 subjects), or placebo (32) at monthly intervals for 1 year. The primary outcome measure was the number of severe exacerbations per subject during the 50-week treatment phase. Secondary outcomes included a change in asthma symptoms, scores on the Asthma Quality of Life Questionnaire (AQLQ, in which scores range from 1 to 7, with lower values indicating more severe impairment and a change of 0.5 unit considered to be clinically important), forced expiratory volume in 1 second (FEV(1)) after use of a bronchodilator, airway hyperresponsiveness, and eosinophil counts in the blood and sputum. RESULTS: Mepolizumab was associated with significantly fewer severe exacerbations than placebo over the course of 50 weeks (2.0 vs. 3.4 mean exacerbations per subject; relative risk, 0.57; 95% confidence interval [CI], 0.32 to 0.92; P=0.02) and with a significant improvement in the score on the AQLQ (mean increase from baseline, 0.55 vs. 0.19; mean difference between groups, 0.35; 95% CI, 0.08 to 0.62; P=0.02). Mepolizumab significantly lowered eosinophil counts in the blood (P<0.001) and sputum (P=0.002). There were no significant differences between the groups with respect to symptoms, FEV(1) after bronchodilator use, or airway hyperresponsiveness. The only serious adverse events reported were hospitalizations for acute severe asthma. CONCLUSIONS: Mepolizumab therapy reduces exacerbations and improves AQLQ scores in patients with refractory eosinophilic asthma. The results of our study suggest that eosinophils have a role as important effector cells in the pathogenesis of severe exacerbations of asthma in this patient population. (Current Controlled Trials number, ISRCTN75169762.)

BACKGROUND: Eosinophilic inflammation, which may be a consequence of interleukin-5 action, is a characteristic feature of some forms of asthma. However, in three previous clinical trials involving patients with asthma, blockade of this cytokine did not result in a significant improvement in outcomes. We studied the prednisone-sparing effect of mepolizumab, a monoclonal antibody against interleukin-5, in a rare subgroup of patients who have sputum eosinophilia and airway symptoms despite continued treatment with prednisone. Secondary objectives were to examine its effect on the number of eosinophils in sputum and blood, symptoms, and airflow limitation. METHODS: In this randomized, double-blind, parallel-group trial involving patients with persistent sputum eosinophilia and symptoms despite prednisone treatment, we assigned 9 patients to receive mepolizumab (administered in five monthly infusions of 750 mg each) and 11 patients to receive placebo. RESULTS: There were 12 asthma exacerbations in 10 patients who received placebo, 9 of whom had sputum eosinophilia at the time of exacerbation. In comparison, only one patient who received mepolizumab had an asthma exacerbation, and this episode was not associated with sputum eosinophilia (P=0.002). Patients who received mepolizumab were able to reduce their prednisone dose by a mean (+/-SD) of 83.8+/-33.4% of their maximum possible dose, as compared with 47.7+/-40.5% in the placebo group (P=0.04). The use of mepolizumab was associated with a significant decrease in the number of sputum and blood eosinophils. Improvements in eosinophil numbers, asthma control, and forced expiratory volume in 1 second were maintained for 8 weeks after the last infusion. There were no serious adverse events. CONCLUSIONS: Mepolizumab reduced the number of blood and sputum eosinophils and allowed prednisone sparing in patients who had asthma with sputum eosinophilia despite prednisone treatment. (ClinicalTrials.gov number, NCT00292877.)

RECORD STATUS: This is a bibliographic record of a published health technology assessment from a member of INAHTA. No evaluation of the quality of this assessment has been made for the HTA database. CITATION: NIHR HSC. Mepolizumab for severe refractory eosinophilic asthma – first line. Birmingham: NIHR Horizon Scanning Centre (NIHR HSC). Horizon Scanning Review. 2014

BACKGROUND: Treatments for Churg-Strauss syndrome (CSS), a rare eosinophilic vasculitis characterized by asthma, sinusitis, peripheral eosinophilia, pulmonary infiltrates, and tissue infiltration, are limited by toxicity or poor efficacy. Levels of IL-5, a cytokine regulating eosinophils, can be increased in patients with CSS. Mepolizumab, a humanized monoclonal anti-IL-5 antibody, decreases steroid requirements in patients with non-CSS hypereosinophilic syndromes. OBJECTIVE: The purpose of this study was to assess whether mepolizumab would safely allow corticosteroid tapering in patients with steroid-dependent CSS while decreasing serum markers of disease activity. METHODS: This open-label pilot study treated 7 patients with 4 monthly doses of mepolizumab to assess whether it safely decreased CSS disease activity and permitted tapering of systemic corticosteroids. RESULTS: Mepolizumab was safe and well tolerated in patients with CSS. Mepolizumab reduced eosinophil counts and allowed for safe corticosteroid reduction in all 7 subjects. On cessation of mepolizumab, CSS manifestations recurred, necessitating corticosteroid bursts. CONCLUSION: Mepolizumab is a safe and well-tolerated therapy in patients with CSS, offering clinical benefit by enabling corticosteroid tapering while maintaining clinical stability.

RATIONALE: Accumulation of eosinophils in the bronchial mucosa of individuals with asthma is considered to be a central event in the pathogenesis of asthma. In animal models, airway eosinophil recruitment and airway hyperresponsiveness in response to allergen challenge are reduced by specific targeting of interleukin-5. A previous small dose-finding study found that mepolizumab, a humanized anti-interleukin-5 monoclonal antibody, had no effect on allergen challenge in humans. OBJECTIVES: To investigate the effect of three intravenous infusions of mepolizumab, 250 or 750 mg at monthly intervals, on clinical outcome measures in 362 patients with asthma experiencing persistent symptoms despite inhaled corticosteroid therapy (400-1,000 mug of beclomethasone or equivalent). METHODS: Multicenter, randomized, double-blind, placebo-controlled study. MEASUREMENTS AND MAIN RESULTS: Morning peak expiratory flow, forced expiratory volume in 1 second, daily beta(2)-agonist use, symptom scores, exacerbation rates, and quality of life measures. Sputum eosinophil levels were also measured in a subgroup of 37 individuals. Mepolizumab was associated with a significant reduction in blood and sputum eosinophils in both treatment groups (blood, P < 0.001 for both doses; sputum, P = 0.006 for 250 mg and P = 0.004 for 750 mg). There were no statistically significant changes in any of the clinical end points measured. There was a nonsignificant trend for decrease in exacerbation rates in the mepolizumab 750-mg treatment group (P = 0.065). CONCLUSIONS: Mepolizumab treatment does not appear to add significant clinical benefit in patients with asthma with persistent symptoms despite inhaled corticosteroid therapy. Further studies are needed to investigate the effect of mepolizumab on exacerbation rates, using protocols specifically tailored to patients with asthma with persistent airway eosinophilia.

RECORD STATUS: None CITATION: National Horizon Scanning Centre. Mepolizumab (Bosatria) for hypereosinophilic syndrome - first line in combination with corticosteroids Birmingham: National Horizon Scanning Centre (NHSC). Horizon Scanning Technology Briefing. 2008

BACKGROUND: Interleukin (IL)-5 is believed to be a key cytokine in eosinophil inflammatory infiltration in asthma. Previous clinical trials have evaluated the efficacy and safety of mepolizumab, a monoclonal antibody against IL-5, in patients with asthma. However, most of these studies were small, the conclusions were inconsistent, and the precise effects are therefore debatable. METHODS: A meta-analysis of randomized placebo-controlled trials was conducted to evaluate the effect of intravenous infusion of mepolizumab on clinical outcomes in patients with asthma. Trials were searched in PubMed, Embase, Web of Science, Cochrane CENTRAL, Scopus, reviews, and reference lists of relevant articles. The outcome variables analyzed included eosinophil counts in blood and sputum, airways outcome measures, exacerbations, asthma control, and quality of life scores. RESULTS: Seven studies met final inclusion criteria (total n = 1131). From the pooled analyses, mepolizumab significantly reduced eosinophils in blood (MD -0.29×10(9)/L, 95% CI -0.44 to -0.14×10(9)/L, P = 0.0001) and sputum (MD -6.05%, 95% CI -9.34 to -2.77%, P = 0.0003). Mepolizumab was also associated with significantly decreased exacerbation risk than placebo (OR 0.30, 95%CI 0.13 to 0.67, P = 0.004), and with a significant improvement in the scores on the Asthma Quality of Life Questionnaire (AQLQ) (MD 0.26, 95% CI 0.03 to 0.49, P = 0.03) in patients with eosinophilic asthma. There were no statistical differences between the groups with respect to FEV1, PEF, or histamine PC20 (all P>0.05), and a non-significant trend for improvement in scores on the Juniper Asthma Control Questionnaire (JACQ) (MD -0.21, 95% CI -0.43 to 0.01, P = 0.06) in the mepolizumab group was observed. CONCLUSIONS: Mepolizumab reduces the risk of exacerbations and improves quality of life in patients with eosinophilic asthma, but no significant improvement in lung function outcomes was observed. Further research is required to establish the possible role of anti-IL-5 as a therapy for asthma.

BACKGROUND: Severe asthma is a heterogeneous disease. Patients with both eosinophilic and allergic asthma phenotypes may be eligible for treatment with mepolizumab and omalizumab. Evidence on the relative effectiveness of these treatments in this 'overlap' population would be informative for clinical and payer decision making. METHODS: A systematic literature review and indirect treatment comparison (Bayesian framework) were performed to assess the comparative effectiveness and tolerability of mepolizumab and omalizumab, as add-ons to standard of care. Studies included in the primary analysis were double-blind, randomized controlled trials, ≥12 weeks' duration enrolling patients with severe asthma with a documented exacerbation history and receiving high-dose inhaled corticosteroids plus ≥1 additional controller. Two populations were examined: patients potentially eligible for 1) both treatments (Overlap population) and 2) either treatment (Trial population). RESULTS: In the Overlap population, no differences between treatments in clinically significant exacerbations and exacerbations requiring hospitalization were found, although trends favored mepolizumab (rate ratio [RR]:0.66 [95% credible intervals (Crl):0.37,1.19]; 0.19[0.02,2.32], respectively). In the Trial population, mepolizumab treatment produced greater reductions in clinically significant exacerbations (RR:0.63 [95% CrI:0.45,0.89]) but not exacerbations requiring hospitalization compared with omalizumab (RR:0.58 [95% Crl: 0.16,2.13]), although the trend favored mepolizumab. Both treatments had broadly comparable effects on lung function, and similar tolerability profiles. CONCLUSIONS: Whilst this analysis has limitations due to a restricted evidence base and residual heterogeneity, it showed that in patients with severe asthma, mepolizumab seems to be at least as effective as omalizumab and that the tolerability profiles of the two treatments did not meaningfully differentiate.

OBJECTIVES: To report on the extended follow-up of relapsing/refractory CSS patients treated with mepolizumab with respect to relapse rates. METHODS: The follow-up consisted of regular clinic visits of patients who received nine infusions of mepolizumab (750mg IV) and switched to methotrexate 0.3mg/kg for maintenance of remission. Glucocorticoids were maintained as low as possible. Disease activity was measured using the Birmingham Vasculitis Activity Score (BVAS). Disease states as remission or relapse were defined according to the EULAR/EUVAS recommendations. The serum eosinophil cationic protein (ECP) was measured regularly and concentrations were correlated with BVAS. RESULTS: The follow-up of the study population under standard methotrexate maintenance therapy was extended to a median of 22 months. Three of nine patients were still in remission at the end of follow-up. During this time five major relapses in three and seven minor relapses in five out of the total nine patients were recognised. ECP levels were found to correlate stronger with the BVAS (r=0.38; p<0.0001) than other measures such as eosinophil counts. CONCLUSIONS: After induction of remission with mepolizumab the majority of patients suffered relapses when switched to methotrexate maintenance therapy. These data suggest that patients with CSS may require long term treatment with mepolizumab. Future trials in CSS should use other doses or dosing intervals for patients in remission. ECP is a promising marker of disease activity in CSS.

OBJECTIVE: The purpose of this study is to examine the comparative efficacy of Omalizumab (OMA) and Mepolizumab (Mepo) in the treatment of severe asthma by performing a network meta-analysis. METHOD: Data Sources: A systematic review of the literature was performed through four databases from their inception to February 2016. STUDY SELECTIONS: Randomized control trials and cohort studies were considered if they addressed the individual efficacy of OMA and Mepo in the treatment of asthma that was not well controlled on inhaled corticosteroids (ICSs) with or without other agents. RESULTS: OMA was significantly better than Mepo in improving the Asthma Quality of Life Questionnaire with a mean difference of 0.38 and a confidence interval of (0.21-0.55), p < 0.0001, without reaching the minimal clinically important difference of 0.5. No significant difference was seen in Asthma Control Questionnaire, forced expiratory volume in second 1 (FEV1), and Peak Expiratory Flow Rate (PEFR) improvement from baseline. Both medications were successful in reducing the calculated annualized rates of asthma exacerbations (AEs) vs placebo by approximately 50%. The heterogeneity score for the different comparisons were elevated except for the PEFR. CONCLUSION: When compared indirectly via a network meta-analysis, the efficacy of OMA and Mepo was similar in the treatment of asthma that was not well controlled on at least high-dose ICS. The high heterogeneity observed and the different selection criteria for the use of the two drugs do not permit us to make any definitive recommendations for the preferential use of OMA vs Mepo in the patient populations studied. However, the current data do not suggest any major differences in efficacy.