Stopping versus continuing long-term mepolizumab treatment in severe eosinophilic asthma (COMET study).

BACKGROUND: The long-term efficacy and safety of mepolizumab for treatment of severe eosinophilic asthma are well established. Here, we examine the clinical impact of stopping mepolizumab after long-term use. METHODS: COMET (NCT02555371) was a randomised, double-blind, placebo-controlled, parallel-group, multicentre study. Patients who had completed COLUMBA (NCT01691859) or COSMEX (NCT02135692) and received continuous mepolizumab treatment for ≥3 years were randomised 1:1 to stop (switch to placebo) or continue subcutaneous mepolizumab 100 mg every 4 weeks for 52 weeks. Primary end-point: time to first clinically significant exacerbation; secondary end-points: time to first exacerbation requiring hospitalisation/emergency department visit, time to decrease in asthma control (≥0.5-point increase in Asthma Control Questionnaire-5 score from COMET baseline) and blood eosinophil count ratio to COMET baseline. Safety was assessed. RESULTS: Patients stopping (n=151) versus continuing (n=144) mepolizumab had significantly shorter times to first clinically significant exacerbation (hazard ratio 1.61, 95% CI 1.17-2.22; p=0.004) and decrease in asthma control (hazard ratio 1.52, 95% CI 1.13-2.02; p=0.005), and higher blood eosinophil counts at week 52 (270 versus 40 cells·µL-1; ratio (stopping versus continuing) 6.19, 95% CI 4.89-7.83; p<0.001). Differences in efficacy outcomes between groups were observed when assessed from week 12 (16 weeks after last mepolizumab dose). Exacerbations requiring hospitalisation/emergency department visit were rare. Adverse events in patients continuing mepolizumab were consistent with previous studies. For patients who stopped mepolizumab, the safety profile was consistent with other eosinophilic asthma populations. CONCLUSION: Patients who stopped mepolizumab had an increase in exacerbations and reduced asthma control versus those who continued.

Mepolizumab improves clinical outcomes in patients with severe asthma and comorbid conditions.

BACKGROUND: Comorbidities can complicate the management of severe asthma; therefore, the presence of comorbid conditions or traits often need to be considered when considering treatment options for patients with severe asthma. The aim of this analysis is to investigate the efficacy of mepolizumab in patients with severe eosinophilic asthma and comorbidities. METHODS: This was a post hoc analysis (GSK ID:209140) of data from the Phase IIb/III studies DREAM, MENSA, SIRIUS, and MUSCA. Patients aged ≥ 12 years with severe eosinophilic asthma were randomized to: mepolizumab 750, 250, or 75 mg intravenously or placebo (DREAM); mepolizumab 75 mg intravenously or 100 mg subcutaneously or placebo (MENSA); or mepolizumab 100 mg subcutaneously or placebo (SIRIUS and MUSCA) every 4 weeks for 24 weeks in SIRIUS and MUSCA, 32 weeks in MENSA or 52 weeks in DREAM. In this analysis the primary endpoint was the annual rate of clinically significant exacerbations; secondary endpoints were Asthma Control Questionnaire-5 score, St George's Respiratory Questionnaire total score, and pre-bronchodilator forced expiratory volume in 1 s at study end. Subgroups were based on comorbidities at baseline. RESULTS: Overall, 1878 patients received placebo (n = 689) or mepolizumab (n = 1189). Across all comorbidity subgroups mepolizumab reduced the rate of clinically significant exacerbations by 44-68% versus placebo, improved Asthma Control Questionnaire-5 score by 0.27-0.59 points, and improved St George's Respiratory Questionnaire total score by 5.0-11.6 points. Pre-bronchodilator forced expiratory volume in 1 s was improved by 27.1-286.9 mL in all but one comorbidity subgroup, the diabetes mellitus subgroup. CONCLUSIONS: Mepolizumab reduces exacerbations, and improves asthma control, health-related quality of life, and lung function in patients with severe eosinophilic asthma despite comorbid conditions, including upper respiratory conditions, psychopathologies, cardiovascular conditions, gastroesophageal reflux disease, diabetes mellitus, and obesity. TRIAL REGISTRATION: https://clinicaltrials.gov/ DREAM, MEA112997/NCT01000506; MENSA, MEA115588/NCT01691521; SIRIUS, MEA115575/NCT01842607; MUSCA, 200862/NCT02281318.

Impact of baseline clinical asthma characteristics on the response to mepolizumab: a post hoc meta-analysis of two Phase III trials.

BACKGROUND: Severe asthma is associated with a broad range of phenotypes and clinical characteristics. This analysis assessed whether select baseline patient characteristics could prognosticate mepolizumab efficacy in severe eosinophilic asthma. METHODS: This was a post hoc meta-analysis of data from the Phase III MENSA (NCT01691521/MEA115588) and MUSCA (NCT02281318/200862) studies. Patients aged ≥ 12 years with severe eosinophilic asthma and a history of exacerbations were randomised to receive placebo (MENSA/MUSCA), mepolizumab 75 mg intravenously (MENSA) or 100 mg subcutaneously (SC) (MENSA/MUSCA) every 4 weeks for 32 (MENSA) or 24 (MUSCA) weeks. The primary endpoint was the annual rate of clinically significant exacerbations; other outcomes included the proportion of patients with no exacerbations and changes from baseline in pre-bronchodilator forced expiratory volume in 1 s (FEV1), St George's Respiratory Questionnaire (SGRQ) total score and Asthma Control Questionnaire (ACQ)-5 score. Analyses were performed by baseline age of asthma onset (< 18 years; 18-40 years; ≥ 40 years); lung function (% predicted FEV1 ≤ 60; 60-80; > 80); airway reversibility (reversible [≥ 12% change in FEV1]; non-reversible [< 12% change in FEV1]); perennial and/or seasonal allergen sensitivity (yes/no); asthma control (uncontrolled [ACQ-5 score ≥ 1.5]; partial/complete control [ACQ-5 score < 1.5]). RESULTS: Overall, 936 patients received mepolizumab 100 mg SC or placebo. Across age at asthma onset, lung function and airway reversibility subgroups, mepolizumab reduced the rate of clinically significant exacerbations by 49-63% versus placebo. Improvements in lung function, SGRQ total score and ACQ-5 score were also seen with mepolizumab versus placebo across most age and lung function subgroups. Clinically significant exacerbations were reduced with mepolizumab versus placebo irrespective of season or allergen sensitivity; SGRQ total and ACQ-5 scores were generally improved across seasons. CONCLUSIONS: Mepolizumab efficacy was consistent for patients with varying age at asthma onset, lung function, airway reversibility and allergen sensitivities at baseline. Our results indicate that mepolizumab is likely to be beneficial for patients with severe eosinophilic asthma with a broad range of baseline clinical characteristics; large-scale real-world studies are needed to confirm the external validity of these findings. Trial registration Post hoc meta-analysis of data from MENSA (NCT01691521/MEA115588) and MUSCA (NCT02281318/200862).

Efficacy and safety of mepolizumab in hypereosinophilic syndrome: A phase III, randomized, placebo-controlled trial.

BACKGROUND: Anti-IL-5 therapy is a potential treatment for patients with hypereosinophilic syndrome (HES), although its clinical efficacy is unclear. OBJECTIVE: We sought to investigate the clinical efficacy and safety of mepolizumab versus placebo in patients with HES. METHODS: This randomized, multicenter, double-blind, placebo-controlled, phase III trial was conducted across 39 centers in 13 countries. Eligible patients had FIP1L1-PDGFRA-negative HES, experienced 2 or more flares (worsening of HES-related symptoms or blood eosinophil count requiring therapeutic escalation) in the previous 12 months, and had a screening blood eosinophil count greater than or equal to 1000 cells/µL. Patients were randomized (1:1) to subcutaneous mepolizumab (300 mg) or placebo every 4 weeks for 32 weeks, plus existing HES therapy. The primary outcome was the proportion of patients with 1 or more flares (worsening of HES-related symptoms necessitating therapy escalation or ≥2 courses of blinded rescue oral corticosteroids) during the study; in addition, patients who withdrew early from the study were counted as having a flare. Safety end points were also assessed. RESULTS: The proportion of patients experiencing 1 or more flares/withdrawing from the study was 50% lower with mepolizumab versus placebo (15 of 54 [28%] vs 30 of 54 [56%]; P = .002). Logistic regression analysis was consistent with the primary analysis (odds ratio, 0.28; 95% CI, 0.12-0.64; P = .003). Similar proportions of patients in the mepolizumab and placebo groups experienced on-treatment adverse events (48 of 54 [89%] vs 47 of 54 [87%]). CONCLUSIONS: Compared with placebo, mepolizumab significantly reduced the occurrence of flares in patients with HES, with no new safety signals identified.

Mepolizumab for Eosinophilic Chronic Obstructive Pulmonary Disease.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) with an eosinophilic phenotype may benefit from treatment with mepolizumab, a monoclonal antibody directed against interleukin-5. METHODS: We performed two phase 3, randomized, placebo-controlled, double-blind, parallel-group trials comparing mepolizumab (100 mg in METREX, 100 or 300 mg in METREO) with placebo, given as a subcutaneous injection every 4 weeks for 52 weeks in patients with COPD who had a history of moderate or severe exacerbations while taking inhaled glucocorticoid-based triple maintenance therapy. In METREX, unselected patients in the modified intention-to-treat population with an eosinophilic phenotype were stratified according to blood eosinophil count (≥150 per cubic millimeter at screening or ≥300 per cubic millimeter during the previous year). In METREO, all patients had a blood eosinophil count of at least 150 per cubic millimeter at screening or at least 300 per cubic millimeter during the previous year. The primary end point was the annual rate of moderate or severe exacerbations. Safety was also assessed. RESULTS: In METREX, the mean annual rate of moderate or severe exacerbations in the modified intention-to-treat population with an eosinophilic phenotype (462 patients) was 1.40 per year in the mepolizumab group versus 1.71 per year in the placebo group (rate ratio, 0.82; 95% confidence interval [CI], 0.68 to 0.98; adjusted P=0.04); no significant between-group differences were found in the overall modified intention-to-treat population (836 patients) (rate ratio, 0.98; 95% CI, 0.85 to 1.12; adjusted P>0.99). In METREO, the mean annual rate of moderate or severe exacerbations was 1.19 per year in the 100-mg mepolizumab group, 1.27 per year in the 300-mg mepolizumab group, and 1.49 per year in the placebo group. The rate ratios for exacerbations in the 100-mg and 300-mg mepolizumab groups versus the placebo group were 0.80 (95% CI, 0.65 to 0.98; adjusted P=0.07) and 0.86 (95% CI, 0.70 to 1.05; adjusted P=0.14), respectively. A greater effect of mepolizumab, as compared with placebo, on the annual rate of moderate or severe exacerbations was found among patients with higher blood eosinophil counts at screening. The safety profile of mepolizumab was similar to that of placebo. CONCLUSIONS: Mepolizumab at a dose of 100 mg was associated with a lower annual rate of moderate or severe exacerbations than placebo among patients with COPD and an eosinophilic phenotype. This finding suggests that eosinophilic airway inflammation contributes to COPD exacerbations. (Funded by GlaxoSmithKline; METREX and METREO ClinicalTrials.gov numbers, NCT02105948 and NCT02105961 .).

Impact of exacerbations on St George's Respiratory Questionnaire score in patients with severe asthma: post hoc analyses of two clinical trials and an observational study.

Objective: To assess the effect of asthma exacerbations and mepolizumab treatment on health status of patients with severe asthma using the St George's Respiratory Questionnaire (SGRQ).Methods: Post hoc analyses were conducted using data from two randomized controlled trials in patients ≥12 years old with severe eosinophilic asthma randomized to receive placebo or mepolizumab 75 mg intravenously (32-week MENSA study) or 100 mg subcutaneously (MENSA/24-week MUSCA studies), and an observational single-visit study in patients with severe asthma (IDEAL). Linear regression models assessed the impact of historical exacerbations on baseline SGRQ total and domain scores (using data from each of the three studies), and within-study severe exacerbations and mepolizumab treatment on end-of-study SGRQ scores (using data from MENSA/MUSCA).Results: Overall, 1755 patients were included (MENSA, N = 540; MUSCA, N = 551; IDEAL, N = 664). In all studies, higher numbers of historical exacerbations were associated with worse baseline SGRQ total scores. Each additional historical exacerbation (beyond the second [MENSA/MUSCA]) or first [IDEAL] was associated with worsening mean total SGRQ scores of +1.5, +1.1 at baseline and +2.3 within the year prior to study enrollment. During MENSA and MUSCA, each within-study severe exacerbation was associated with a worsening in total SGRQ score of +2.4 and +3.4 points at study end. Independent of exacerbation reduction, mepolizumab accounted for an improvement in total SGRQ score of -5.3 points (MENSA) and -6.2 points (MUSCA).Conclusions: These findings support an association between a higher number of exacerbations and worse health status in patients with severe (eosinophilic) asthma.

Long-term safety and pharmacodynamics of mepolizumab in children with severe asthma with an eosinophilic phenotype.

BACKGROUND: Mepolizumab is approved for patients with severe asthma with an eosinophilic phenotype aged 12 or more (United States) or 6 or more (European Union) years, but its long-term use in children aged 6 to 11 years has not yet been assessed. OBJECTIVE: We sought to assess the long-term safety, efficacy, and pharmacodynamics of mepolizumab in children aged 6 to 11 years with severe asthma with an eosinophilic phenotype. METHODS: In this open-label, uncontrolled, repeat-dose extension study (NCT02377427), children aged 6 to 11 years with severe asthma with an eosinophilic phenotype (blood eosinophil counts ≥150 cells/µL at screening or ≥300 cells/µL in the previous year) received a body weight-dependent dose of subcutaneous mepolizumab of 40 mg (<40 kg) or 100 mg (≥40 kg) over 52 weeks. End points included the incidence of adverse events (AEs) and immunogenicity (primary), absolute blood eosinophil counts (cells per microliter; secondary), and annualized exacerbation rates and asthma control questionnaire/childhood asthma control test scores (exploratory). RESULTS: Over 52 weeks, 30 children received mepolizumab; 27 (90%) and 7 (23%) experienced on-treatment AEs and serious AEs, respectively. No serious AEs were treatment related. There were no fatal AEs. No specific patterns of AEs were evident, and no anti-drug antibody or neutralizing antibody responses were reported. Compared with baseline values, mepolizumab treatment reduced blood eosinophil counts and asthma exacerbations and improved asthma control across all treatment groups. CONCLUSION: Long-term safety, pharmacodynamic, and efficacy data from this study support a positive benefit-risk profile for mepolizumab in children with severe asthma with an eosinophilic phenotype and were similar to data in studies in adults and adolescents.

Evaluation of clinical benefit from treatment with mepolizumab for patients with eosinophilic granulomatosis with polyangiitis.

BACKGROUND: In a recent phase III trial (NCT02020889) 53% of mepolizumab-treated versus 19% of placebo-treated patients with eosinophilic granulomatosis with polyangiitis (EGPA) achieved protocol-defined remission. OBJECTIVE: We sought to investigate post hoc the clinical benefit of mepolizumab in patients with EGPA using a comprehensive definition of benefit encompassing remission, oral glucocorticoid (OGC) dose reduction, and EGPA relapses. METHODS: The randomized, placebo-controlled, double-blind, parallel-group trial recruited patients with relapsing/refractory EGPA receiving stable OGCs (prednisolone/prednisone, ≥7.5-50 mg/d) for 4 or more weeks. Patients received 300 mg of subcutaneous mepolizumab or placebo every 4 weeks for 52 weeks. Clinical benefit was defined post hoc as follows: remission at any time (2 definitions used), 50% or greater OGC dose reduction during weeks 48 to 52, or no EGPA relapses. The 2 remission definitions were Birmingham Vasculitis Activity Score of 0 plus OGC dose of 4 mg/d or less (remission 1/clinical benefit 1) or 7.5 mg/d or less (remission 2/clinical benefit 2). Clinical benefit was assessed in all patients and among subgroups with a baseline blood eosinophil count of less than 150 cells/µL, baseline OGC dosage of greater than 20 mg/d, or weight of greater than 85 kg. RESULTS: With mepolizumab versus placebo, 78% versus 32% of patients experienced clinical benefit 1, and 87% versus 53% of patients experienced clinical benefit 2 (both P < .001). Significantly more patients experienced clinical benefit 1 with mepolizumab versus placebo in the blood eosinophil count less than 150 cells/µL subgroup (72% vs 43%, P = .033) and weight greater than 85 kg subgroup (68% vs 23%, P = .005); in the OGC greater than 20 mg/d subgroup, results were not significant but favored mepolizumab (60% vs 36%, P = .395). CONCLUSION: When a comprehensive definition of clinical benefit was applied to data from a randomized controlled trial, 78% to 87% of patients with EGPA experienced benefit with mepolizumab.

Assessment of the long-term safety of mepolizumab and durability of clinical response in patients with severe eosinophilic asthma.

BACKGROUND: Mepolizumab has demonstrated favorable safety and efficacy profiles in placebo-controlled trials of 12 months' duration or less; however, long-term data are lacking. OBJECTIVE: We sought to evaluate the long-term safety and efficacy of mepolizumab in patients with severe eosinophilic asthma (SEA). METHODS: COLUMBA (Open-label Long Term Extension Safety Study of Mepolizumab in Asthmatic Subjects, NCT01691859) was an open-label extension study in patients with SEA previously enrolled in DREAM (Dose Ranging Efficacy And Safety With Mepolizumab in Severe Asthma, NCT01000506). Patients received 100 mg of subcutaneous mepolizumab every 4 weeks plus standard of care until a protocol-defined stopping criterion was met. Safety end points included frequency of adverse events (AEs), serious AEs, and AEs of special interest. Efficacy end points included annualized exacerbation rates, changes from baseline in Asthma Control Questionnaire 5 scores, and blood eosinophil counts. Immunogenicity was also assessed. RESULTS: Overall, 347 patients were enrolled for an average of 3.5 years (maximum, 4.5 years; total exposure, 1201 patient-years). On-treatment AEs were reported in 94% of patients (exposure-adjusted rate, 3688 events/1000 patient-years). The most frequently reported on-treatment AEs were respiratory tract infection, headache, bronchitis, and asthma worsening. Seventy-nine (23%) patients experienced 1 or more on-treatment serious AEs; there were 6 deaths, none of which were assessed as related to mepolizumab. For patients with 156 weeks or greater enrollment, the exacerbation rate was 0.74 events/y (weeks 0-156), a 56% reduction from the off-treatment period between DREAM and COLUMBA. For all patients, at the first postbaseline assessment, the mean Asthma Control Questionnaire 5 score was reduced by 0.47 points, and blood eosinophil counts were reduced by 78%, with similar improvements maintained throughout the study. The immunogenicity profile (8% anti-drug antibodies) was consistent with previous studies. CONCLUSION: These data support the long-term safety and efficacy of mepolizumab in patients with SEA.

Mepolizumab reduces exacerbations in patients with severe eosinophilic asthma, irrespective of body weight/body mass index: meta-analysis of MENSA and MUSCA.

BACKGROUND: We assessed the efficacy of the licensed mepolizumab dose (100 mg subcutaneously [SC]) in patients with severe eosinophilic asthma according to body weight/body mass index (BMI). METHODS: This was a post hoc individual patient-level meta-analysis of data from the Phase 3 studies MENSA (MEA115588/NCT01691521) and MUSCA (200862/NCT02281318). Patients aged ≥12 years with severe eosinophilic asthma and a history of exacerbations were randomised to 4-weekly placebo, mepolizumab 75 mg intravenously (IV) or 100 mg SC (MENSA) or placebo or mepolizumab 100 mg SC (MUSCA) for 32 (MENSA) or 24 (MUSCA) weeks. The primary endpoint was the annual rate of clinically significant exacerbations; other outcomes included the proportion of patients with no exacerbations, lung function, St George's Respiratory Questionnaire (SGRQ) and Asthma Control Questionnaire-5 (ACQ-5) scores and blood eosinophil counts. Analyses were performed by baseline body weight and BMI (≤60, > 60-75, > 75-90, > 90, < 100, ≥100 kg; ≤25, > 25-30, > 30, < 36, ≥36 kg/m2). RESULTS: Overall, 936 patients received placebo or mepolizumab 100 mg SC. Across all body weight/BMI categories, mepolizumab reduced the rate of clinically significant exacerbations by 49-70% versus placebo. Improvements with mepolizumab versus placebo were also seen in lung function in all body weight/BMI categories except > 90 kg; improvements in SGRQ and ACQ-5 scores were seen across all categories. CONCLUSIONS: Mepolizumab 100 mg SC has consistent clinical benefits in patients with severe eosinophilic asthma across a range of body weights and BMIs. Data show that the fixed-dose regimen of mepolizumab is suitable, without the need for weight-based dosing. TRIAL REGISTRATION: This manuscript is a post hoc meta-analysis of data from the Phase 3 studies MENSA and MUSCA. ClinicalTrials.gov, NCT01691521 (MEA115588; MENSA). Registered September 24, 2012. ClinicalTrials.gov, NCT02281318 (200862; MUSCA). Registered November 3, 2014.

Oral corticosteroid dose changes and impact on peripheral blood eosinophil counts in patients with severe eosinophilic asthma: a post hoc analysis.

BACKGROUND: An inverse relationship between oral corticosteroid (OCS) dose and peripheral blood eosinophil (PBE) count is widely recognized in patients with severe eosinophilic asthma; however, there are limited data available to quantify this relationship. This post hoc analysis of the SIRIUS study (NCT01691508) examined the impact of weekly incremental OCS dose reductions on PBE counts during the 3-8-week optimization phase of the study. METHODS: SIRIUS was a randomized, double-blind study involving patients with severe asthma (≥12 years old), which included an initial OCS dose optimization phase prior to randomization. Regression analysis assuming a linear relationship between change in OCS dose and change in log (PBE count) during the optimization phase was used to estimate the changes in PBE count following specific decreases in OCS dose. RESULTS: All 135 patients from the SIRIUS intent-to-treat population were included in this analysis. During the optimization period, 44% (60/135) of patients reduced their OCS dose, with an increase in geometric mean PBE count of 110 cells/µL (200 to 310 cells/µL; geometric mean ratio from beginning to end of the optimization phase: 1.52) recorded in these patients. The model estimated that reduction of daily OCS dose by 5 mg/day led to a 41% increase in PBE count (mean ratio to beginning of optimization phase: 1.41 [95% confidence interval (CI); 1.22, 1.63]). CONCLUSION: These data confirmed and quantified the inverse association between OCS dose and PBE count. These insights will help to inform clinicians when tapering OCS doses in patients with severe eosinophilic asthma.

Biologic treatment eligibility for real-world patients with severe asthma: The IDEAL study.

OBJECTIVES: Severe asthma comprises several distinct phenotypes. Consequently, patients with severe asthma can be eligible for more than one biologic treatment targeting Th2 inflammation, such as anti-interleukin (IL)-5 and anti-immunoglobulin (Ig) E. The objective of this study was to describe treatment eligibility and overlap in treatment eligibility for mepolizumab (anti-IL-5), omalizumab (anti-IgE) and reslizumab (anti-IL-5) in patients with severe asthma, who were recruited from clinical practice. METHODS: This cross-sectional, single-visit, observational study in six countries enrolled patients with severe asthma (defined by American Thoracic Society/European Respiratory Society guidelines). Assessable patients were analysed as a total cohort and a sub-cohort, who were not currently receiving omalizumab. Treatment eligibility was defined according to the local prescribing information or protocol-defined inclusion/exclusion criteria. Patients currently receiving omalizumab were automatically categorised as omalizumab-eligible. RESULTS: The total cohort comprised 670 patients who met the analysis criteria, of whom 20% were eligible for mepolizumab, 31-41% were eligible for omalizumab (depending on eligibility criteria used), and 5% were eligible for reslizumab. In patients not currently receiving omalizumab (n = 502), proportions eligible for each biologic were similar (mepolizumab: 20%, reslizumab 6%) or lower (omalizumab 7-21%) than those for the total cohort. Overlap in treatment eligibility varied; in mepolizumab-eligible patients not currently receiving omalizumab (n = 101), 27-37% were omalizumab-eligible and 18% were reslizumab-eligible. CONCLUSIONS: Treatment eligibility for mepolizumab and omalizumab was higher than that for reslizumab. Although there was some overlap in treatment eligibility, the patient groups eligible for treatment with anti-IL-5 or anti-IgE therapies were often distinct, emphasising the different phenotypes and endotypes in severe asthma.

Clinical Development of Mepolizumab for the Treatment of Severe Eosinophilic Asthma: On the Path to Personalized Medicine.

The development of mepolizumab, an anti-IL-5 monoclonal antibody for the treatment of severe eosinophilic asthma, is an example of a clinical development program that evolved over time based on sound, basic scientific principles. Initial clinical data on the effects of mepolizumab on lung function in a general asthmatic population were disappointing. However, it became clear that mepolizumab may be more effective against other clinical endpoints, particularly asthma exacerbations, in patients with more severe disease. Furthermore, a developing understanding of asthma disease pathobiology led to the identification of an appropriate target population and predictive biomarker for mepolizumab treatment: patients with severe eosinophilic asthma and blood eosinophil count. Mepolizumab use provides clinically meaningful benefits in this target population, fulfilling an unmet need. This Clinical Commentary Review describes the clinical development of mepolizumab and details of how this program informed the development of other biologic therapies in patients with severe asthma. This account highlights how a personalized approach toward treatment of patients with severe eosinophilic asthma, supported by a large body of scientific evidence, ultimately led to new and effective treatments and improved patient outcomes.

Mepolizumab for Eosinophil-Associated COPD: Analysis of METREX and METREO.

Background: A pre-specified meta-analysis of individual patient data from the 52-week METREX and METREO trials, which investigated mepolizumab for chronic obstructive pulmonary disease (COPD) in patients with blood eosinophil counts ≥150 cells/µL (screening) or ≥300 cells/µL (prior year) and frequent exacerbations, enables more robust characterization of mepolizumab efficacy in COPD and exploration of the relationship between blood eosinophil count and treatment responses. Methods: In METREX (117106/NCT02105948) and METREO (117113/NCT02105961), randomized patients received mepolizumab or placebo added to existing inhaled corticosteroid (ICS)-based triple maintenance therapy. The annual rate of moderate/severe exacerbations (primary endpoint) was compared between subcutaneous (SC) mepolizumab 100 mg versus placebo (primary comparison of interest) and all doses (100 mg and 300 mg SC) versus placebo in patients with blood eosinophil counts ≥150 cells/µL at screening or ≥300 cells/µL in the prior year. Secondary/other endpoints included time to first moderate/severe exacerbation, exacerbations leading to emergency department visit/hospitalization and health-related quality of life (HRQoL). A predictive model of the relationship between screening blood eosinophil counts and exacerbation rates included data from all randomized patients. Results: In total, 1510 patients were randomized in METREX and METREO and 1136 patients were included in the pre-specified meta-analysis. From the meta-analysis, mepolizumab 100 mg SC significantly reduced annual moderate/severe exacerbation rates versus placebo by 18% (rate ratio: 0.82; 95% confidence interval: 0.71, 0.95; p=0.006) and delayed time to first moderate/severe exacerbation (hazard ratio: 0.80 [0.68, 0.94]; p=0.006). Mepolizumab 100 mg SC versus placebo numerically reduced exacerbations leading to ED visits/hospitalization and improved HRQoL. A modelling approach demonstrated increasing efficacy for moderate/severe exacerbations with increasing screening blood eosinophil count; this relationship was more pronounced for exacerbations requiring oral corticosteroids (post hoc). The all-doses comparison had similar results. Conclusion: Mepolizumab reduces exacerbations in patients with eosinophil-associated COPD. Results suggest that blood eosinophil counts (≥150 cells/µL at screening or ≥300 cells/µL in the prior year) allow for identification of patients with COPD who experience exacerbations while treated with maximal ICS-based triple maintenance therapy who are likely to benefit from mepolizumab.

The Pharmacokinetics and Relative Bioavailability of Mepolizumab 100 mg Liquid Formulation Administered Subcutaneously to Healthy Participants: A Randomized Trial.

This study compared the pharmacokinetic (PK) profile of a new liquid formulation of mepolizumab with the established lyophilized formulation. In this open-label, parallel-group, single-dose study (NCT03014674; GSK ID: 204958), healthy participants were randomized (1:1:1) to receive a single mepolizumab dose (100 mg) administered subcutaneously as liquid in a single-use prefilled syringe or single-use prefilled autoinjector, or as a lyophilized formulation. Maximum plasma concentration, area under the plasma concentration-time curve from time zero (predose) to time of last quantifiable concentration (AUC0-t ), and AUC from time zero to infinity (AUC0-∞ ) as well as additional PK parameters, safety assessments, and blood eosinophil count were evaluated. In total, 244 participants received study drug. All PK parameters were similar across the 3 groups; 90% confidence intervals for maximum plasma concentration, AUC0-t , and AUC0-∞ treatment ratios (liquid prefilled syringe or autoinjector vs lyophilized formulation) were within conventional bioequivalence bounds (0.80-1.25), demonstrating statistical PK comparability. On-treatment adverse event incidence was 29% to 38%. Mepolizumab liquid formulation administered via prefilled syringe or autoinjector had similar PK properties to the lyophilized formulation, with no safety concerns identified.

Multinational cohort study of mortality in patients with asthma and severe asthma.

BACKGROUND: Data on the risk of death following an asthma exacerbation are scarce. With this multinational cohort study, we assessed all-cause mortality rates, mortality rates following an exacerbation, and patient characteristics associated with all-cause mortality in asthma. METHODS: Asthma patients aged ≥18 years and with ≥1 year of follow-up were identified in 5 European electronic databases from the Netherlands, Italy, UK, Denmark and Spain during the study period January 1, 2008-December 31, 2013. Patients with asthma-COPD overlap were excluded. Severe asthma was defined as use of high dose ICS + use of a second controller. Severe asthma exacerbations were defined as emergency department visits, hospitalizations or systemic corticosteroid use, all for reason of asthma. RESULTS: The cohort consisted of 586,436 asthma patients of which 42,611 patients (7.3%) had severe asthma. The age and sex standardized all-cause mortality rates ranged between databases from 5.2 to 9.5/1000 person-years (PY) in asthma, and between 11.3 and 14.8/1000 PY in severe asthma. The all-cause mortality rate in the first week following a severe asthma exacerbation ranged between 14.1 and 59.9/1000 PY. Mortality rates remained high in the first month following a severe asthma exacerbation and decreased thereafter. Higher age, male gender, comorbidity, smoking, and previous severe asthma exacerbations were associated with mortality. CONCLUSION: All-cause mortality following a severe exacerbation is high, especially in the first month following the event. Smoking cessation, comorbidity-management and asthma-treatment focusing on the prevention of exacerbations might reduce associated mortality.

Disease burden and efficacy of mepolizumab in patients with severe asthma and blood eosinophil counts of ≥150-300 cells/µL.

BACKGROUND: In patients with severe eosinophilic asthma, treatment decisions can be determined by blood eosinophil counts; however, a specific blood eosinophil threshold has not been defined for starting mepolizumab treatment. METHODS: We summarized the disease burden and efficacy of mepolizumab in patients with severe eosinophilic asthma and baseline blood eosinophil counts of ≥150-300 cells/µL and ≥300 cells/µL using data from the mepolizumab clinical development program (DREAM [NCT01000506], MENSA [NCT01691521], SIRIUS [NCT01691508] and MUSCA [NCT02281318]). RESULTS: The morbidity of asthma in patients with baseline blood eosinophil counts ≥150-300 cells/µL was similar to that in patients with blood eosinophil counts ≥300 cells/µL, with similar rates of exacerbations (2.8-3.5 events/year versus 2.8-3.8 events/year, respectively), asthma related emergency room visits, intubations and near fatal events. Use of maintenance oral corticosteroids (OCS) was similar across blood eosinophil count subgroups. Reductions in the rates of clinically significant exacerbations with mepolizumab versus placebo ranged from 27 to 49% in patients with blood eosinophil counts of ≥150-300 cells/µL for DREAM, MENSA and MUSCA. The odds of achieving a reduction in OCS in SIRIUS was 2.03 (95% CI: 0.53, 7.75) versus 1.79 (95% CI: 0.71, 4.52) in patients with blood eosinophil counts ≥150-300 cells/µL and ≥300 cells/µL, respectively. CONCLUSION: There is a high unmet clinical need in patients with blood eosinophil counts ≥150-300 cells/µL, and a clinically meaningful benefit is seen with mepolizumab in this subgroup. Mepolizumab is an efficacious treatment option for patients with blood eosinophil counts ≥150 cells/µL.