Type 2 severe asthma: pathophysiology and treatment with biologics.

INTRODUCTION: The hallmark of most patients with severe asthma is type 2 inflammation, driven by innate and adaptive immune responses leading to either allergic or non-allergic eosinophilic infiltration of airways. The cellular and molecular pathways underlying severe type 2 asthma can be successfully targeted by specific monoclonal antibodies. AREAS COVERED: This review article provides a concise overview of the pathophysiology of type 2 asthma, followed by an updated appraisal of the mechanisms of action and therapeutic efficacy of currently available biologic treatments used for management of severe type 2 asthma. Therefore, all reported information arises from a wide literature search performed on PubMed. EXPERT OPINION: The main result of the recent advances in the field of anti-asthma biologic therapies is the implementation of a personalized medicine approach, aimed to achieve clinical remission of severe asthma. Today this accomplishment is made possible by the right choice of the most beneficial biologic drug for the pathologic traits characterizing each patient, including type 2 severe asthma and its comorbidities.

Biomarkers and clinical outcomes after tezepelumab cessation: Extended follow-up from the 2-year DESTINATION study.

BACKGROUND: Long-term tezepelumab treatment in the DESTINATION study (NCT03706079) resulted in reduced asthma exacerbations, reduced biomarker levels, and improved lung function and symptom control in patients with severe, uncontrolled asthma. OBJECTIVE: To explore the time course of changes in biomarkers and clinical manifestations after treatment cessation after 2 years of tezepelumab treatment. METHODS: DESTINATION was a 2-year, phase 3, multicenter, randomized, placebo-controlled, double-blind study of tezepelumab treatment in patients (12-80 years old) with severe asthma. Patients received their last treatment doses at week 100 and could enroll in an extended follow-up period from weeks 104 to 140. Change over time in key biomarkers and clinical outcomes were assessed in tezepelumab vs placebo recipients for 40 weeks after stopping treatment. RESULTS: Of 569 patients enrolled in the extended follow-up period, 426 were included in the analysis (289 received tezepelumab and 137 placebo). In the 40-week period after the last tezepelumab dose, blood eosinophil counts, fractional exhaled nitric oxide levels, and Asthma Control Questionnaire-6 scores gradually increased from weeks 4 to 10, with a gradual reduction in pre-bronchodilator forced expiratory volume in 1 second such that blood eosinophil counts, fractional exhaled nitric oxide levels, and clinical outcomes returned to placebo levels; however, none of these outcomes returned to baseline levels. Total IgE levels increased later from week 28 and remained well below placebo and baseline levels during the 40-week period after the last tezepelumab dose. CONCLUSION: This analysis reveals the benefits of continued tezepelumab treatment in the management of patients with severe, uncontrolled asthma, compared with stopping treatment after 2 years. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03706079.

Characterization of Moderate and Severe Asthma Exacerbations in the CAPTAIN Study.

BACKGROUND: Limited data exist on the relative impact of moderate and severe exacerbations on asthma control and impairment. OBJECTIVE: To explore data from the CAPTAIN trial to evaluate the relationship between first moderate or severe exacerbation and changes in lung function, symptoms, physical activity limitation scores, and short-acting ß2-agonist (SABA) usage to determine the clinical relevance of moderate events. METHODS: CAPTAIN was a phase IIIA 24- to 52-week, multicenter, international, randomized controlled trial evaluating efficacy and safety of fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI in patients with uncontrolled asthma on inhaled corticosteroid/long-acting ß2-agonist. Outcomes reported include first postrandomization exacerbation event by severity (wk 1-52), frequency and duration of moderate and severe exacerbations, and time course of changes over ± 14-day peri-exacerbation period for lung function, symptoms, limitations, and SABA use. RESULTS: Of the intent-to-treat population (n = 2,436), 550 patients (23%) continued to 52 weeks. There were 529 moderate and 546 severe exacerbations. Lung function changes were similar, but symptom, physical activity limitation scores, and SABA use were higher, for severe versus moderate exacerbations. Lung function decline preceded increases in symptom, physical activity limitation scores, and SABA use, irrespective of exacerbation severity. Lung function variables, limitation scores, and SABA use returned to pre-exacerbation baseline after approximately 8 to 12 days for both exacerbation severities. CONCLUSIONS: Whereas severe events were associated with greater impact on symptoms, physical activity limitations, and SABA use, onset and time to resolution were generally similar for moderate and severe events. Both exacerbation severities represent clinically important deteriorations comprising clinical and functional changes.

The carbon footprint of as-needed budesonide/formoterol in mild asthma: a post hoc analysis.

INTRODUCTION: The use of pressurised metered-dose inhalers (pMDIs) and asthma exacerbations necessitating healthcare reviews contribute substantially to the global carbon footprint of healthcare. It is possible that a reduction in carbon footprint could be achieved by switching patients with mild asthma from salbutamol pMDI reliever-based therapy to inhaled corticosteroid-formoterol dry powder inhaler (DPI) reliever therapy, as recommended by the Global Initiative for Asthma. METHODS: This post hoc analysis included all 668 adult participants in the Novel START trial, who were randomised 1:1:1 to treatment with as-needed budesonide/formoterol DPI, as-needed salbutamol pMDI or maintenance budesonide DPI plus as-needed salbutamol pMDI. The primary outcome was carbon footprint of asthma management, expressed as kilograms of carbon dioxide equivalent emissions (kgCO2e) per person-year. Secondary outcomes explored the effect of baseline symptom control and adherence (maintenance budesonide DPI arm only) on carbon footprint. RESULTS: As-needed budesonide/formoterol DPI was associated with 95.8% and 93.6% lower carbon footprint compared with as-needed salbutamol pMDI (least-squares mean 1.1 versus 26.2 kgCO2e; difference -25.0, 95% CI -29.7 to -20.4; p<0.001) and maintenance budesonide DPI plus as-needed salbutamol pMDI (least-squares mean 1.1 versus 17.3 kgCO2e; difference -16.2, 95% CI -20.9 to -11.6; p<0.001), respectively. There was no statistically significant evidence that treatment differences in carbon footprint depended on baseline symptom control or adherence in the maintenance budesonide DPI arm. CONCLUSIONS: The as-needed budesonide/formoterol DPI treatment option was associated with a markedly lower carbon footprint than as-needed salbutamol pMDI and maintenance budesonide DPI plus as-needed salbutamol pMDI.

Dupilumab Reduces Exacerbations Independent of Changes in Biomarkers in Moderate-to-Severe Asthma.

BACKGROUND: Changes from baseline in fractional exhaled nitric oxide (FeNO) and blood eosinophil count (Eos) may be related to efficacy outcomes in dupilumab-treated patients with moderate-to-severe asthma. OBJECTIVE: This post hoc analysis investigated biomarker changes in placebo- and dupilumab-treated patients with uncontrolled moderate-to-severe asthma enrolled in QUEST (NCT02414854). METHODS: Spline analyses of annualized severe exacerbation rate (AER) and change from baseline in pre-bronchodilator (BD) forced expiratory volume in 1 second (FEV1) at week 52 were performed as a function of the fold change in FeNO at week 52 and the maximum fold change in Eos over weeks 0-12 (also change from baseline in pre-BD FEV1 at week 12). RESULTS: The combined placebo and dupilumab groups comprised 638 and 1264 patients, respectively. FeNO levels declined rapidly by week 2 and then gradually to week 52 in patients treated with dupilumab versus placebo; Eos, after initially increasing with dupilumab, declined slightly from baseline in both treatment groups. AER during QUEST showed no significant association with the change in biomarkers in either treatment group. The change from baseline in pre-BD FEV1 at week 52 was inversely associated with the fold change in FeNO in both groups, with a significant difference between the dupilumab and placebo curves (P = .014), and was positively associated with the fold change in Eos in both groups (P = .022). CONCLUSIONS: Relative changes in FeNO and Eos were not associated with AER, regardless of treatment arm. However, changes in both biomarkers showed a predictive value for lung function improvement; for FeNO, this was specific to the dupilumab treatment arm.

IL-5 antagonism reverses priming and activation of eosinophils in severe eosinophilic asthma.

Eosinophils are key effector cells mediating airway inflammation and exacerbation in patients with severe eosinophilic asthma. They are present in increased numbers and activation states in the airway mucosa and lumen. Interleukin-5 (IL-5) is the key eosinophil growth factor that is thought to play a role in eosinophil priming and activation. However, the mechanism of these effects is still not fully understood. The anti-IL-5 antibody mepolizumab reduces eosinophil counts in the airway modestly but has a large beneficial effect on the frequency of exacerbations of severe eosinophilic asthma, suggesting that reduction in eosinophil priming and activation is of central mechanistic importance. In this study, we used the therapeutic effect of mepolizumab and single-cell ribonucleic acid sequencing to investigate the mechanism of eosinophil priming and activation by IL-5. We demonstrated that IL-5 is a dominant driver of eosinophil priming and plays multifaceted roles in eosinophil function. It enhances eosinophil responses to other stimulators of migration, survival, and activation by activating phosphatidylinositol-3-kinases, extracellular signal-regulated kinases, and p38 mitogen-activated protein kinases signaling pathways. It also enhances the pro-fibrotic roles of eosinophils in airway remodeling via transforming growth factor-ß pathway. These findings provide a mechanistic understanding of eosinophil priming in severe eosinophilic asthma and the therapeutic effect of anti-IL-5 approaches in the disease.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma.

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges. Disruption of epithelial integrity is a key factor contributing to multiple processes underlying asthma pathology. In this review, we first discuss the unmet need in asthma management and provide an overview of the structure and function of the airway epithelium. We then focus on key pathophysiological changes that occur in the airway epithelium, including epithelial barrier disruption, immune hyperreactivity, remodelling, mucus hypersecretion and mucus plugging, highlighting how these processes manifest clinically and how they might be targeted by current and novel therapeutics.

Baseline Characteristics and ICS/LAMA/LABA Response in Asthma: Analyses From the CAPTAIN Study.

BACKGROUND: Findings from CAPTAIN (NCT02924688) suggest that treatment response to fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) differs according to baseline type 2 inflammation markers in patients with moderate to severe asthma. Understanding how other patient physiologic and clinical characteristics affect response to inhaled therapies may guide physicians toward a personalized approach for asthma management. OBJECTIVE: To investigate, using CAPTAIN data, the predictive value of key demographic and baseline physiologic variables in patients with asthma (lung function, bronchodilator reversibility, age, age at asthma onset) on response to addition of the long-acting muscarinic antagonist UMEC to inhaled corticosteroid/long-acting ß2-agonist combination FF/VI, or doubling the FF dose. METHODS: Prespecified and post hoc analyses of CAPTAIN data were performed using categorical and continuous variables of key baseline characteristics to understand their influence on treatment outcomes (lung function [trough FEV1], annualized rate of moderate/severe exacerbations, and asthma control [Asthma Control Questionnaire]) following addition of UMEC to FF/VI or doubling the FF dose in FF/VI or FF/UMEC/VI. RESULTS: Adding UMEC to FF/VI led to greater improvements in trough FEV1 versus doubling the FF dose across all baseline characteristics assessed. Doubling the FF dose was generally associated with numerically greater reductions in the annualized rate of moderate/severe exacerbations compared with adding UMEC, independent of baseline characteristics. Adding UMEC and/or doubling the FF dose generally led to improvements in Asthma Control Questionnaire scores irrespective of baseline characteristics. CONCLUSIONS: Unlike previous findings with type 2 biomarkers, lung function, bronchodilator reversibility, age and age at asthma onset do not appear to predict response to inhaled therapy.

Phenotyping of Severe Asthma in the Era of Broad-Acting Anti-Asthma Biologics.

Severe asthma is associated with significant morbidity and mortality despite the maximal use of inhaled corticosteroids and additional controller medications, and has a high economic burden. Biologic therapies are recommended for the management of severe, uncontrolled asthma to help to prevent exacerbations and to improve symptoms and health-related quality of life. The effective management of severe asthma requires consideration of clinical heterogeneity that is driven by varying clinical and inflammatory phenotypes, which are reflective of distinct underlying disease mechanisms. Phenotyping patients using a combination of clinical characteristics such as the age of onset or comorbidities and biomarker profiles, including blood eosinophil counts and levels of fractional exhaled nitric oxide and serum total immunoglobulin E, is important for the differential diagnosis of asthma. In addition, phenotyping is beneficial for risk assessment, selection of treatment, and monitoring of the treatment response in patients with asthma. This review describes the clinical and inflammatory phenotypes of asthma, provides an overview of biomarkers routinely used in clinical practice and those that have recently been explored for phenotyping, and aims to assess the value of phenotyping in severe asthma management in the current era of biologics.

Dupilumab sustains lung function improvements in patients with moderate-to-severe asthma.

BACKGROUND: TRAVERSE (NCT02134028), a phase 3 open-label extension study, assessed dupilumab safety and efficacy in patients with asthma aged ≥12 years who completed a previous dupilumab asthma study. This analysis evaluated changes in multiple lung function parameters in patients with moderate-to-severe asthma with elevated type 2 biomarkers (baseline eosinophils ≥150 cells·µL-1 or fractional exhaled nitric oxide ≥25 ppb) who completed QUEST (parent study) and 2 years of dupilumab treatment in TRAVERSE. METHODS: Endpoints analyzed included: pre-bronchodilator forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory flow (FEF25-75 %), and pre- and post-bronchodilator FEV1/FVC at parent study baseline (PSBL) at Weeks 0, 2, 48, and 96 in TRAVERSE, as well as pre- and post-bronchodilator FEV1 slopes in QUEST and TRAVERSE. Statistical analyses were descriptive. RESULTS: Dupilumab improved pre-bronchodilator FEV1, FVC, and FEF25-75 % in QUEST; these improvements were sustained in TRAVERSE. In QUEST patients who received placebo, dupilumab initiation in TRAVERSE resulted in rapid lung function improvements. Mean (standard deviation) changes from PSBL at TRAVERSE Weeks 48 and 96 in pre-bronchodilator FEV1 were 0.52 (0.59) and 0.45 (0.49) L in the dupilumab/dupilumab group and 0.47 (0.42) and 0.44 L (0.45) in the placebo/dupilumab group, respectively. Similar trends were observed for FVC and FEF25-75 %. Dupilumab also improved FEV1 slopes in QUEST and TRAVERSE. CONCLUSION: Dupilumab demonstrated sustained improvements across multiple spirometric lung function measurements for up to 3 years; patients who received placebo in QUEST experienced rapid lung function improvement upon initiation of dupilumab in TRAVERSE.

Blood eosinophils and fractional exhaled nitric oxide are prognostic and predictive biomarkers in childhood asthma.

BACKGROUND: Blood eosinophils and fractional exhaled nitric oxide (Feno) are prognostic biomarkers for exacerbations and predict lung function responses to dupilumab in adolescents and adults with asthma. OBJECTIVE: We evaluated the relationship between baseline blood eosinophils and Feno and response to dupilumab in children with asthma. METHODS: Children aged 6 to 11 years with uncontrolled moderate-to-severe asthma (n = 408) were randomized to receive dupilumab 100/200 mg by body weight or volume-matched placebo every 2 weeks for 52 weeks. Annualized exacerbation rate (AER) reduction and least squares mean change in prebronchodilator percent predicted forced expiratory volume in 1 second (ppFEV1) at week 12 were assessed according to cutoff baseline levels for Feno (<20 ppb vs ≥20 ppb) and blood eosinophil count (<150, ≥150 to <300, ≥300 to <500, and ≥500 cells/µL). Quadrant analyses in populations defined by biomarker thresholds and spline models across continuous end points assessed the relationship with Feno and eosinophil count. Interaction testing evaluated the independent roles of Feno and blood eosinophils as predictive markers. RESULTS: Exacerbation risk and magnitude of AER reduction increased in subgroups with higher baseline biomarker levels. Quadrant analyses revealed that disease of patients with either elevated Feno or eosinophil counts demonstrated a clinical response to dupilumab. Interaction testing indicated blood eosinophil counts or Feno independently added value as predictive biomarkers. CONCLUSIONS: In children with uncontrolled moderate-to-severe asthma, blood eosinophil counts and Feno are clinically relevant biomarkers to identify those at risk for asthma exacerbations, as well as those with disease with clinical response to dupilumab. TRIAL REGISTRATION: Liberty Asthma VOYAGE ClinicalTrials.gov NCT02948959.

Tezepelumab in patients with allergic and eosinophilic asthma.

Asthma is a heterogeneous disease commonly driven by allergic and/or eosinophilic inflammation, both of which may be present in severe disease. Most approved biologics for severe asthma are indicated for specific phenotypes and target individual downstream type 2 components of the inflammatory cascade. Tezepelumab, a human monoclonal antibody (immunoglobulin G2λ), binds specifically to thymic stromal lymphopoietin (TSLP), an epithelial cytokine that initiates and sustains allergic and eosinophilic inflammation in asthma. By blocking TSLP, tezepelumab has demonstrated efficacy across known asthma phenotypes and acts upstream of all current clinically used biomarkers. In a pooled analysis of the phase 2b PATHWAY (NCT02054130) and phase 3 NAVIGATOR (NCT03347279) studies, compared with placebo, tezepelumab reduced the annualized asthma exacerbation rate over 52 weeks by 62% (95% confidence interval [CI]: 53, 70) in patients with perennial aeroallergen sensitization (allergic asthma); by 71% (95% CI: 62, 78) in patients with a baseline blood eosinophil count ≥300 cells/µL; and by 71% (95% CI: 59, 79) in patients with allergic asthma and a baseline blood eosinophil count ≥300 cells/µL. This review examines the efficacy and mode of action of tezepelumab in patients with allergic asthma, eosinophilic asthma and coexisting allergic and eosinophilic phenotypes.

Dupilumab efficacy in high sleep disturbance management among patients with type 2 asthma.

BACKGROUND: Patients with asthma often experience sleep disturbances. We assessed the 5-item Asthma Control Questionnaire (ACQ-5) score ≥2.5 as a useful threshold to identify patients with moderate-to-severe type 2 asthma and high sleep disturbance (HSD) and investigated dupilumab efficacy on clinical and sleep-related outcomes among patients with HSD. METHODS: QUEST (NCT02414854) data were used in this post hoc analysis. A composite endpoint from validated patient-reported outcomes was developed to identify patients with HSD using sleep-related items from the ACQ-5, Asthma-Related Quality-of-Life Questionnaire, Rhino-Conjunctivitis Quality-of-Life Questionnaire, and Sino-Nasal Outcome Test-22. Impairment in at least 1 item was considered an indication of HSD. Change from baseline to Week 52 in nighttime symptoms, ACQ-5 score, lung function, annualized severe exacerbation rates (AER), and short-acting ß-agonists use during treatment was used to assess dupilumab efficacy. RESULTS: In type 2 asthma patients, 64% had HSD at baseline; of those with ACQ-5 ≥2.5 at baseline, 82% had HSD. In this population, dupilumab reduced nighttime symptoms and ACQ-5 score by 0.31 and 0.56 points, respectively, by Week 52 versus placebo, and led to a 66% reduction in AER during QUEST and 0.34 L improvement in pre-bronchodilator (pre-BD) forced expiratory volume in 1 s (FEV1) at Week 52. CONCLUSION: A majority of patients with moderate-to-severe type 2 asthma with ACQ-5 ≥2.5 at baseline had HSD. Dupilumab reduced nighttime symptoms and exacerbations, and improved lung function, overall asthma control, and quality of life. Further studies are needed to confirm the association between ACQ-5 score ≥2.5 and higher sleep disturbance rates.