Should Airway Hyper-Responsiveness Be Included in the Definition of Clinical Remission With Biologic Therapy in Severe Asthma.

Airway hyper-responsiveness (AHR) is a tenet of the persistent asthma phenotype along with reversible airway obstruction and type 2 (T2) inflammation. Indirect acting challenges such as mannitol are more closely related to the underlying T2 inflammatory process as compared with direct challenges. In this review article, we summarise the current literature and explore the future role of mannitol AHR in clinical remission with biologics.

Efficacy of biologic therapy on airway hyperresponsiveness in asthma.

Airway hyperresponsiveness refers to an exaggerated bronchial constrictor response to a given exogenous inhaled agent and is governed by airway smooth muscle along with mucosal inflammation in asthma. In recent years, the advent of biologics and antialarmins has transformed severe asthma treatment in terms of reducing oral-corticosteroid-requiring exacerbations and improving disease control, asthma quality of life, and spirometry-measured lung function. In contrast, there have been comparatively fewer studies investigating the efficacy of biologics in airway hyperresponsiveness. In this focused review, we summarize the existing evidence base in this area regarding omalizumab, mepolizumab, benralizumab, and tezepelumab.

Impact of Biologic Therapy on the Small Airways Asthma Phenotype.

The small airways dysfunction (SAD) asthma phenotype is characterised by narrowing of airways < 2 mm in diameter between generations 8 and 23 of the bronchial tree. Recently, this has become particularly relevant as measurements of small airways using airway oscillometry for example, are strong determinants of asthma control and exacerbations in moderate-to-severe asthma. The small airways can be assessed using spirometry as forced expiratory flow rate between 25 and 75% of forced vital capacity (FEF25-75) and has been deemed more accurate in detecting small airways dysfunction than forced expiratory volume in 1 s (FEV1). Oscillometry as the heterogeneity in resistance between 5 and 20 Hz (R5-R20), low frequency reactance at 5 Hz (X5) or area under the reactance curve between 5 Hz and the resonant frequency can also be used to assess the small airways. The small airways can also be assessed using the multiple breath nitrogen washout (MBNW) test giving rise to values including functional residual capacity, lung clearance index and ventilation distribution heterogeneity in the conducting (Scond) and the acinar (Sacin) airways. The ATLANTIS group showed that the prevalence of small airways disease in asthma defined on FEF25-75, oscillometry and MBNW all increased with progressive GINA asthma disease stages. As opposed to topical inhaler therapy that might not adequately penetrate the small airways, it is perhaps more intuitive that systemic anti-inflammatory therapy with biologics targeting downstream cytokines and upstream epithelial anti-alarmins may offer a promising solution to SAD. Here we therefore aim to appraise the available evidence for the effect of anti-IgE, anti-IL5 (Rα), anti-IL4Rα, anti-TSLP and anti-IL33 biologics on small airways disease in patients with severe asthma.

Randomized controlled trial of triple versus dual inhaler therapy on small airways in smoking asthmatics.

BACKGROUND: Smoking worsens underlying asthma inflammation and also induces resistance to inhaled corticosteroids (ICS). Small airways dysfunction measured by impulse oscillometry (IOS) is associated with worse control. OBJECTIVES: We investigated the effects on small airways of adding long-acting beta-agonist (LABA) alone or with long-acting muscarinic antagonist (LAMA) to ICS in asthmatic smokers. METHODS: Sixteen current smokers were enrolled: mean age 44 year, FEV1 84%, FEF25-75 47%, R5 158%, ACQ 1.69, 20 pack year . Patients were converted to a reference ICS as HFA-BDP during initial run-in at median dose of 800 µg/day. Open label olodaterol 5 µg od (OLO) or olodaterol 5 µg/tiotropium 5 µg od (OLO/TIO) was added to HFA-BDP for median duration of 3 weeks in a randomized cross over design, including run-in and washout periods on HFA-BDP. IOS and spirometry were measured after each treatment (BDP/OLO/TIO or BDP/OLO) and at baseline after run-in and washout (BDP). RESULTS: After chronic dosing, IOS outcomes at trough except for R20 were all significantly improved with OLO/TIO compared to OLO. For the primary end-point of total airway resistance (as R5), the mean difference (95%CI) at trough was 0.06 (0.015-0.10) kPa/l/s, peripheral airways resistance (as R5-R20) 0.03 (0.003-0.06) kPa/l/s, peripheral lung reactance area (as AX) 0.38 (0.08-0.68) kPa/l and resonant frequency (as RF) 2.28 (0.45-4.12) Hz. FEF25-75 at trough was also better with OLO/TIO vs TIO: 0.93 (0.86 - 0.95) l/s while FEV1 was not different. CONCLUSIONS: ICS/LABA/LAMA was superior to ICS/LABA on trough small airway outcomes in asthma patients who smoke.

Current appraisal of single inhaler triple therapy in COPD.

A single inhaler containing inhaled corticosteroid (ICS)/long-acting beta-agonist (LABA)/long-acting muscarinic antagonist (LAMA) is a more convenient way of delivering triple therapy in patients with COPD. Single triple therapy has been shown to be superior at reducing exacerbations and improving quality of life compared to LABA/LAMA, especially in patients with a prior history of frequent exacerbations and blood eosinophilia, who have ICS responsive disease. The corollary is that patients with infrequent exacerbations who are noneosinophilic may be safely de-escalated from triple therapy to LABA/LAMA without loss of control. Pointedly, there is a substantially increased risk of pneumonia associated with the triple therapy containing fluticasone furoate but not beclometasone dipropionate or budesonide. Since triple therapy is also better than ICS/LABA at reducing exacerbations and improving lung function, symptoms, and quality of life, this brings into question the rationale for using ICS/LABA. Hence, we propose a simplified pragmatic decision process based on symptoms, prior to exacerbation history, and blood eosinophils to select which patients should be given a single triple inhaler or LABA/LAMA. Differences in patient preference of inhaler device, formulations and drugs will also determine which triple inhaler prescribers elect to use.

Emerging role of long acting muscarinic antagonists for asthma.

Acetlycholine is involved in the control of airway smooth muscle constriction and in recruitment of inflammatory cells via neuronal and paracrine effects on muscarinic type 3 receptors. Long acting muscarinic antagonists (LAMA) are well established in guidelines for COPD but are not currently licensed for use in asthma. There are emerging data from key clinical trials to show that LAMA may confer bronchodilator effects and improved control when used in addition to inhaled corticosteroid (ICS) alone or in conjunction with long acting ß-adrenoceptor agonists (LABA). Further studies in persistent asthmatic patients are required to evaluate ICS sparing effects of LAMA looking particularly at airway hyper-responsiveness and surrogate inflammatory markers, in addition to evaluation of possible synergy between LAMA and LABA when given together. Future possible development of combination inhalers comprising ICS/LAMA or ICS/LAMA/LABA will require long term studies looking at asthma control and exacerbations in both adult and paediatric patients.

Optimised glucocorticoid therapy: the sharpening of an old spear.

CONTEXT: Glucocorticoids are frequently and successfully used drugs that mediate important immunosuppressive and anti-inflammatory effects. These drugs are also relatively inexpensive, but it is their broad range of adverse reactions that continuously stimulate efforts to optimise glucocorticoid treatment. STARTING POINT: Last year, Mary Leonard and colleagues studied 60 children and adolescents with nephrotic syndrome intermittently treated with high-dose glucocorticoids (N Engl J Med 2004; 351: 868-75). The patients received an average of 23 g glucocorticoids and were significantly shorter, had a significantly greater body-mass index, and the prevalence of obesity was significantly higher than in controls. The expected deficits in the bone-mineral content of the spine or whole body were not seen, although this finding could be attributed to the highly increased body-mass index of many of the patients. WHERE NEXT: Glucocorticoids are urgently needed to treat a wide range of diseases in children and adults. Therefore strategies such as preferred local application or fine-tuned dose regimens have been developed over the past five decades to improve the benefit-risk ratio. However, these efforts with conventional glucocorticoid drugs seem to have almost reached their limits. A further improvement needs qualitatively new drugs, which are currently in the development pipeline, with the most promising being the nitrosoglucocorticoids (nitrosteroids) and selective glucocorticoid-receptor agonists.

Effects of butterbur treatment in intermittent allergic rhinitis: a placebo-controlled evaluation.

BACKGROUND: Butterbur (Petasites hybridus) contains the active ingredient petasin, which exhibits antileukotriene and antihistamine activity. Previous studies of intermittent allergic rhinitis (IAR) have demonstrated a comparable response to butterbur compared with a histamine H1-receptor antagonist on the 36-Item Short-Form Health Survey quality-of-life score. However, there has been no placebo-controlled study of the effects of butterbur use on objective and subjective outcomes in IAR. OBJECTIVE: To evaluate the effects of treatment with butterbur vs placebo on objective and subjective outcomes in IAR. METHODS: A double-blind, placebo-controlled, crossover study was carried out during the grass pollen season in Tayside, Scotland. Thirty-five patients (14 men and 21 women) with IAR received butterbur, 50 mg twice daily, or placebo for 2 weeks. Domiciliary measurements were taken in the morning and evening for peak nasal inspiratory flow (PNIF) (the primary outcome variable), nasal and eye symptoms, and rhinoconjunctivitis-specific quality-of-life score. RESULTS: Butterbur treatment had no significant effect on PNIF, total nasal symptom score, eye symptom score, or quality of life compared with placebo use. Mean (SEM) morning and evening PNIF values were 107 (6) and 114 (6) L/min, respectively, for butterbur vs 105 (6) and 117 (6) L/min for placebo. Mean (SEM) morning and evening total nasal symptom scores (maximum total score, 12) were 3.4 (0.4) and 3.5 (0.4), respectively, for butterbur vs 3.7 (0.3) and 3.8 (0.4) for placebo. CONCLUSIONS: There was no significant clinical efficacy of butterbur use vs placebo use on objective and subjective outcomes in IAR. Further studies are now indicated to investigate the use of butterbur in persistent allergic rhinitis.

The effects of butterbur on the histamine and allergen cutaneous response.

BACKGROUND: Butterbur or Petasites hybridus is an herbal remedy that exhibits antihistamine and antileukotriene activity and has been shown to attenuate the response to adenosine monophosphate challenge in patients with allergic rhinitis and asthma. However, no data are available regarding its effects on the histamine and allergen cutaneous response. OBJECTIVE: To evaluate the effects of butterbur compared with fexofenadine and montelukast on the histamine and allergen wheal and flare cutaneous responses. METHODS: Atopic patients were randomized into a double-blind, double-dummy, crossover study to receive for 1 week butterbur, 50 mg twice daily (8 AM and 10 PM); fexofenadine, 180 mg once daily (10 PM), and placebo once daily (8 AM); montelukast, 10 mg once daily (10 PM), and placebo once daily (8 AM); or placebo twice daily (8 AM and 10 PM). Patients attended the department at 10 AM and had measurements of the cutaneous wheal and flare responses to histamine, allergen, and saline control at 10-minute intervals for 60 minutes. RESULTS: Twenty patients completed the study. The mean +/- SE histamine wheal and flare responses, respectively, were significantly attenuated (P < .05) by fexofenadine (9.4 +/- 1.8 mm2 and 13.5 +/- 3.2 mm2) compared with placebo (15.5 +/- 3.3 mm2 and 179.8 +/- 74.3 mm2) but not by butterbur (16.4 +/- 2.1 mm2 and 297.7 +/- 121.2 mm2) or montelukast (19 +/- 1.9 mm2 and 240.2 +/- 66.6 mm2). The allergen wheal and flare responses, respectively, were also significantly attenuated (P < .05) by fexofenadine (31.1 +/- 6.3 mm2 and 256.9 +/- 86.5 mm2) compared with placebo (65.4 +/- 15.2 mm2 and 1,014.5 +/- 250.0 mm2) but not by butterbur (50.4 +/- 9.2 mm2 and 1,110.3 +/- 256.1 mm2) or montelukast (58.8 +/- 9.1 mm2 and 1,463.6 +/- 295.6 mm2). CONCLUSIONS: Butterbur did not produce any significant effects on the histamine and allergen cutaneous response compared with placebo, whereas mediator antagonism with fexofenadine but not montelukast produced significant attenuation. This finding would suggest that butterbur may not be effective in allergic skin disease.

The presence of emphysema does not affect the systemic bioactivity of inhaled fluticasone in severe chronic obstructive pulmonary disease.

AIMS: To assess the systemic bioactivity of fluticasone proprionate (FP) 2000 micro g daily on sensitive adrenal and bone markers in severe chronic obstructive pulmonary disease (COPD) patients with or without significant emphysema. METHODS: Ten patients without emphysema (COPD group: age 55 years, FEV(1) 51% predicted and DL(CO) 83% predicted) and 10 patients with emphysema (COPDE group: age 59 years, FEV(1) 43% predicted and DL(CO) 49% predicted) received FP 2000 micro g daily via a spacer for 2 weeks. There was a 1-week washout period prior to FP treatment where patients were given salmeterol and oxitropium, after stopping their usual inhaled corticosteroids for the duration of the study. Measurements including overnight 10 h urinary cortisol excretion corrected for creatinine (OUCC) and serum osteocalcin concentrations were performed at baseline following washout and after 2 weeks of FP. RESULTS: Values for OUCC and serum osteocalcin concentrations pre- and post-FP were not significantly different between the COPD and COPDE groups. There was significant suppression of OUCC (nmol mmol(-1)) by FP treatment within the COPD group (P = 0.03): 7.86 vs 4.64 (95% CI on the difference 0.47, 5.98), and within the COPDE group (P = 0.006): 7.13 vs 4.27 (95% CI on the difference: 1.03, 4.69). Likewise, there was significant suppression of osteocalcin concentration (nmol l(-1)) by FP treatment within the COPD group (P = 0.04): 7.24 vs 6.34 (95% CI on the difference: 0.01, 1.78), and within the COPDE group (P = 0.03): 6.92 vs 5.72 (95% CI on the difference: 0.12, 2.29). CONCLUSIONS: Severe COPD patients who are receiving high dose FP are susceptible to the development of systemic adverse effects, irrespective of the presence of emphysema.

Relationship of skin-prick reactivity to aeroallergens and hyperresponsiveness to challenges with methacholine and adenosine monophosphate.

BACKGROUND: Clarification of the relationship between atopy and bronchial hyperresponsiveness (BHR), both key features of asthma, is critical to our understanding of the disease. We therefore investigated the putative relationship between skin-prick reactivity to aeroallergens and BHR to direct and indirect stimuli. METHODS: We performed a retrospective analysis of data from 332 patients presenting with a diagnosis of asthma. Patients were characterized by skin prick tests (SPT), spirometry and bronchial challenge with methacholine and adenosine monophosphate (AMP). RESULTS: For patients who had BHR to methacholine but not AMP, the presence of atopy was associated with a lower PD20 (the provocative dose of methacholine producing a fall in FEV1 of 20%), amounting to a geometric mean (95% confidence interval (CI)) of 2.3-fold (1.4-4.0) difference. Furthermore, the number of skin-prick positive (SPP) responses was related to methacholine reactivity: 0-1 SPP, PD20 = 69.9 micro g; 2-4 SPP, PD20 = 47.8 micro g; 5-8 SPP, PD20 = 35.6 micro g. There was a 2.0- fold (1.1-3.6) difference between the groups with a low (0-1 SPP) and high (5-8 SPP) degree of skin-prick reactivity. A similar pattern was seen when data were analyzed including only perennial allergens. Spirometry was unrelated to the degree of skin-prick reactivity. DISCUSSION: These results suggest that skin-prick reactivity to aeroallergens is associated with BHR to methacholine.