Real-world impact of mepolizumab in patients with life-threatening asthma: US insurance claims database analysis

PURPOSE

Patients with life-threatening asthma typically experience recurrent exacerbations, are dependent on oral corticosteroids (OCSs), and have considerable asthma-related health care costs. Data on the impact of mepolizumab on exacerbations and OCS use in patients with life-threatening asthma in real-world clinical practice are limited. This study assessed the impact of mepolizumab on exacerbation rates and OCS use in patients with life-threatening asthma in a real-word setting.

METHODS

This retrospective study utilized data from US administrative claims from patients with life-threatening asthma. Eligible patients were treated between November 1, 2015, and December 31, 2017; were ≥12 years of age upon mepolizumab initiation (index date); and had undergone at least two mepolizumab administrations during the 6 months postindex. Data from the 12 months before (baseline) and after (follow-up) index were collected, with each patient serving as his or her own control. Life-threatening asthma was defined as at least three exacerbations and/or at least one asthma-related hospitalization during baseline, and/or a history of endotracheal intubation. Asthma exacerbation frequency and OCS use were assessed.

FINDINGS

The analysis included 327 patients who received a mean (SD) of 10.6 (4.3) mepolizumab doses during follow-up. The percentage of patients experiencing at least one exacerbation and the mean exacerbation rate were significantly reduced from baseline to follow-up with mepolizumab, from 94.5% to 67.9% (P < 0.001), and from 3.2 to 1.5 events per patient per year, corresponding to a 53.1% relative reduction (P < 0.001). The percentage of patients with OCS claims was reduced by 12.6%, from 99.1% to 86.5% (P < 0.001). Of the patients who had a reduction in mean daily OCS use, most (57.9%, 140/242) had a reduction in mean daily OCS use of at least 50%.

IMPLICATIONS

These data from patients with life-threatening asthma in clinical practice demonstrated that asthma exacerbation and OCS use were significantly reduced with mepolizumab treatment.

Effect of tezepelumab on airway inflammatory cells, remodelling, and hyperresponsiveness in patients with moderate-to-severe uncontrolled asthma (CASCADE): a double-blind, randomised, placebo-controlled, phase 2 trial

BACKGROUND

Tezepelumab is a human monoclonal antibody that blocks the activity of thymic stromal lymphopoietin (TSLP), an epithelial cell-derived cytokine. In phase 2b and 3 studies, tezepelumab significantly reduced exacerbations versus placebo in patients with severe uncontrolled asthma, irrespective of baseline levels of type 2 inflammatory biomarkers. We investigated the mechanism of action of tezepelumab by assessing its effects on airway inflammatory cells, airway remodelling, and airway hyperresponsiveness.

METHODS

CASCADE was an exploratory, double-blind, randomised, placebo-controlled, parallel-group, phase 2 study done in 27 medical centres in Canada, Denmark, Germany, the UK, and the USA. Adults aged 18-75 years with uncontrolled, moderate-to-severe asthma were randomly assigned (1:1) to receive tezepelumab 210 mg or placebo administered subcutaneously every 4 weeks for a planned 28 weeks, extended to up to 52 weeks if COVID-19-related disruption delayed participants' end-of-treatment assessments. Randomisation was balanced and stratified by blood eosinophil count. The primary endpoint was the change from baseline to the end of treatment in the number of airway submucosal inflammatory cells in bronchoscopic biopsy samples. Eosinophils, neutrophils, CD3⁺ T cells, CD4⁺ T cells, tryptase⁺ mast cells, and chymase⁺ mast cells were evaluated separately. This endpoint was also assessed in subgroups according to baseline type 2 inflammatory biomarker levels, including blood eosinophil count. Airway remodelling was assessed via the secondary endpoints of change from baseline in reticular basement membrane thickness and epithelial integrity (proportions of denuded, damaged, and intact epithelium). Exploratory outcomes included airway hyperresponsiveness to mannitol. All participants who completed at least 20 weeks of study treatment, had an end-of-treatment visit up to 8 weeks after the last dose of study drug, and had evaluable baseline and end-of-treatment bronchoscopies were included in the primary efficacy analysis. All participants who received at least one dose of study drug were included in the safety analyses. This study is registered with ClinicalTrials.gov, NCT03688074.

FINDINGS

Between Nov 2, 2018, and Nov 16, 2020, 250 patients were enrolled, 116 of whom were randomly assigned (59 to tezepelumab, 57 to placebo). 48 in the tezepelumab group and 51 in the placebo group completed the study and were assessed for the primary endpoint. Treatment with tezepelumab resulted in a nominally significantly greater reduction from baseline to the end of treatment in airway submucosal eosinophils versus placebo (ratio of geometric least-squares means 0·15 [95% CI 0·05-0·41]; nominal p<0·0010), with the difference seen across all baseline biomarker subgroups. There were no significant differences between treatment groups in the other cell types evaluated (ratio of geometric least-squares means: neutrophils 1·36 [95% CI 0·94-1·97]; CD3⁺ T cells 1·12 [0·86-1·46]; CD4⁺ T cells 1·18 [0·90-1·55]; tryptase⁺ mast cells 0·83 [0·61-1·15]; chymase⁺ mast cells 1·19 [0·67-2·10]; all p>0·10). In assessment of secondary endpoints, there were no significant differences between treatment groups in reticular basement membrane thickness and epithelial integrity. In an exploratory analysis, the reduction in airway hyperresponsiveness to mannitol was significantly greater with tezepelumab versus placebo (least-squares mean change from baseline in interpolated or extrapolated provoking dose of mannitol required to induce ≥15% reduction in FEV₁ from baseline: tezepelumab 197·4 mg [95% CI 107·9 to 286·9]; placebo 58·6 mg [-30·1 to 147·33]; difference 138·8 [14·2 to 263·3], nominal p=0·030). Adverse events were reported in 53 (90%) patients in the tezepelumab group and 51 (90%) patients in the placebo group, and there were no safety findings of concern.

INTERPRETATION

The improvements in asthma clinical outcomes observed in previous studies with tezepelumab are probably driven, at least in part, by reductions in eosinophilic airway inflammation, as shown here by reduced airway eosinophil counts regardless of baseline blood eosinophil count. Tezepelumab also reduced airway hyperresponsiveness to mannitol, indicating that TSLP blockade might have additional benefits in asthma beyond reducing type 2 airway inflammation.

FUNDING

AstraZeneca and Amgen.

Investigational therapeutics targeting the IL-4/IL-13/STAT-6 pathway for the treatment of asthma

Asthma is a complex, persistent, inflammatory disease characterised by airway hyperresponsiveness in association with airway inflammation. Studies suggest that regular use of high-dose inhaled corticosteroids and long-acting bronchodilators or omalizumab (a humanised monoclonal antibody that binds to immunoglobulin E and is often used as next-step therapy) may not be sufficient to provide asthma control in all patients, highlighting an important unmet need. Interleukin-4, interleukin-13, and the signal transducer and activator of transcription factor-6 are key components in the development of airway inflammation, mucus production, and airway hyperresponsiveness in asthma. Biological compounds targeting these molecules may provide a new therapeutic modality for patients with uncontrolled severe asthma. The purpose of this review is to summarise current studies of compounds targeting the interleukin-4/interleukin-13 pathway and to provide a rationale for the development of such compounds for this use.