Elliot Israel

Identification of Asthma Phenotypes Using Cluster Analysis in the Severe Asthma Research Program

RATIONALE The Severe Asthma Research Program cohort includes subjects with persistent asthma who have undergone detailed phenotypic characterization. Previous univariate methods compared features of mild, moderate, and severe asthma. OBJECTIVES To identify novel asthma phenotypes using an unsupervised hierarchical cluster analysis. METHODS Reduction of the initial 628 variables to 34 core variables was achieved by elimination of redundant data and transformation of categorical variables into ranked ordinal composite variables. Cluster analysis was performed on 726 subjects. MEASUREMENTS AND MAIN RESULTS Five groups were identified. Subjects in Cluster 1 (n = 110) have early onset atopic asthma with normal lung function treated with two or fewer controller medications (82%) and minimal health care utilization. Cluster 2 (n = 321) consists of subjects with early-onset atopic asthma and preserved lung function but increased medication requirements (29% on three or more medications) and health care utilization. Cluster 3 (n = 59) is a unique group of mostly older obese women with late-onset nonatopic asthma, moderate reductions in FEV(1), and frequent oral corticosteroid use to manage exacerbations. Subjects in Clusters 4 (n = 120) and 5 (n = 116) have severe airflow obstruction with bronchodilator responsiveness but differ in to their ability to attain normal lung function, age of asthma onset, atopic status, and use of oral corticosteroids. CONCLUSIONS Five distinct clinical phenotypes of asthma have been identified using unsupervised hierarchical cluster analysis. All clusters contain subjects who meet the American Thoracic Society definition of severe asthma, which supports clinical heterogeneity in asthma and the need for new approaches for the classification of disease severity in asthma.

Use of regularly scheduled albuterol treatment in asthma: genotype-stratified, randomised, placebo-controlled cross-over trial.

BACKGROUND The issue of whether regular use of an inhaled beta2-adrenergic agonist worsens airflow and clinical outcomes in asthma is controversial. Retrospective studies have suggested that adverse effects occur in patients with a genetic polymorphism that results in homozygosity for arginine (Arg/Arg), rather than glycine (Gly/Gly), at aminoacid residue 16 of the beta2-adrenergic receptor. However, the existence of any genotype-dependent difference has not been tested in a prospective clinical trial. METHODS Patients with mild asthma, not using a controller medication, were enrolled in pairs matched for forced expiratory volume in 1 s (FEV1) according to whether they had the Arg/Arg (n=37; four of 41 matches withdrew before randomisation) or Gly/Gly (n=41) genotype. Regularly scheduled treatment with albuterol or placebo was given in a masked, cross-over design, for 16-week periods. During the study, as-needed albuterol use was discontinued and ipratropium bromide was used as needed. Morning peak expiratory flow rate (PEFR) was the primary outcome variable. The primary comparisons were between treatment period for each genotype; the secondary outcome was a treatment by genotype effect. Analyses were by intention to treat. FINDINGS During the run-in period, when albuterol use was kept to a minimum, patients with the Arg/Arg genotype had an increase in morning PEFR of 23 L/min (p=0.0162); the change in patients with the Gly/Gly genotype was not significant (2 L/min; p=0.8399). During randomised treatment, patients with the Gly/Gly genotype had an increase in morning PEFR during treatment with regularly scheduled albuterol compared with placebo (14 L/min [95% CI 3 to 25]; p=0.0175). By contrast, patients with the Arg/Arg genotype had lower morning PEFR during treatment with albuterol than during the placebo period, when albuterol use was limited (-10 L/min [-19 to -2]; p=0.0209). The genotype-attributable treatment difference was therefore -24 L/min (-37 to -12; p=0.0003). There were similar genotype-specific effects in FEV1, symptoms, and use of supplementary reliever medication. INTERPRETATION Genotype at the 16th aminoacid residue of the beta2-adrenergic receptor affects the long-term response to albuterol use. Bronchodilator treatments avoiding albuterol may be appropriate for patients with the Arg/Arg genotype.

Pharmacogenetic association between ALOX5 promoter genotype and the response to anti-asthma treatment.

Clinically similar asthma patients may develop airway obstruction by different mechanisms. Asthma treatments that specifically interfere with the 5-lipoxygenase (ALOX5) pathway provide a method to identify those patients in whom the products of the ALOX5 pathway (that is, the leukotrienes) contribute to the expression of the asthma phenotype. Failure of an asthma patient to respond to treatment with ALOX5-pathway modifiers indicates that leukotrienes are not critical to the expression of the asthmatic phenotype in that patient. We previously defined a family of DNA sequence variants in the core promoter of the gene ALOX5 (on chromosome 10q11.2) associated with diminished promoter-reporter activity in tissue culture. Because expression of ALOX5 is in part transcriptionally regulated, we reasoned that patients with these sequence variants may have diminished gene transcription, and therefore decreased ALOX5 product production and a diminished clinical response to treatment with a drug targeting this pathway. Such an effect indicates an interaction between gene promoter sequence variants and drug-treatment responses, that is, a pharmacogenetic effect of a promoter sequence on treatment responses.

Effectiveness and safety of bronchial thermoplasty in the treatment of severe asthma: a multicenter, randomized, double-blind, sham-controlled clinical trial.

RATIONALE Bronchial thermoplasty (BT) is a bronchoscopic procedure in which controlled thermal energy is applied to the airway wall to decrease smooth muscle. OBJECTIVES To evaluate the effectiveness and safety of BT versus a sham procedure in subjects with severe asthma who remain symptomatic despite treatment with high-dose inhaled corticosteroids and long-acting beta(2)-agonists. METHODS A total of 288 adult subjects (Intent-to-Treat [ITT]) randomized to BT or sham control underwent three bronchoscopy procedures. Primary outcome was the difference in Asthma Quality of Life Questionnaire (AQLQ) scores from baseline to average of 6, 9, and 12 months (integrated AQLQ). Adverse events and health care use were collected to assess safety. Statistical design and analysis of the primary endpoint was Bayesian. Target posterior probability of superiority (PPS) of BT over sham was 95%, except for the primary endpoint (96.4%). MEASUREMENTS AND MAIN RESULTS The improvement from baseline in the integrated AQLQ score was superior in the BT group compared with sham (BT, 1.35 +/- 1.10; sham, 1.16 +/- 1.23 [PPS, 96.0% ITT and 97.9% per protocol]). Seventy-nine percent of BT and 64% of sham subjects achieved changes in AQLQ of 0.5 or greater (PPS, 99.6%). Six percent more BT subjects were hospitalized in the treatment period (up to 6 wk after BT). In the posttreatment period (6-52 wk after BT), the BT group experienced fewer severe exacerbations, emergency department (ED) visits, and days missed from work/school compared with the sham group (PPS, 95.5, 99.9, and 99.3%, respectively). CONCLUSIONS BT in subjects with severe asthma improves asthma-specific quality of life with a reduction in severe exacerbations and healthcare use in the posttreatment period. Clinical trial registered with www.clinialtrials.gov (NCT00231114).

Tiotropium Bromide Step-Up Therapy for Adults with Uncontrolled Asthma

BACKGROUND Long-acting beta-agonist (LABA) therapy improves symptoms in patients whose asthma is poorly controlled by an inhaled glucocorticoid alone. Alternative treatments for adults with uncontrolled asthma are needed. METHODS In a three-way, double-blind, triple-dummy crossover trial involving 210 patients with asthma, we evaluated the addition of tiotropium bromide (a long-acting anticholinergic agent approved for the treatment of chronic obstructive pulmonary disease but not asthma) to an inhaled glucocorticoid, as compared with a doubling of the dose of the inhaled glucocorticoid (primary superiority comparison) or the addition of the LABA salmeterol (secondary noninferiority comparison). RESULTS The use of tiotropium resulted in a superior primary outcome, as compared with a doubling of the dose of an inhaled glucocorticoid, as assessed by measuring the morning peak expiratory flow (PEF), with a mean difference of 25.8 liters per minute (P<0.001) and superiority in most secondary outcomes, including evening PEF, with a difference of 35.3 liters per minute (P<0.001); the proportion of asthma-control days, with a difference of 0.079 (P=0.01); the forced expiratory volume in 1 second (FEV1) before bronchodilation, with a difference of 0.10 liters (P=0.004); and daily symptom scores, with a difference of -0.11 points (P<0.001). The addition of tiotropium was also noninferior to the addition of salmeterol for all assessed outcomes and increased the prebronchodilator FEV1 more than did salmeterol, with a difference of 0.11 liters (P=0.003). CONCLUSIONS When added to an inhaled glucocorticoid, tiotropium improved symptoms and lung function in patients with inadequately controlled asthma. Its effects appeared to be equivalent to those with the addition of salmeterol. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT00565266.).

The Effects of a 5-Lipoxygenase Inhibitor on Asthma Induced by Cold, Dry Air

BACKGROUND The enzyme 5-lipoxygenase catalyzes the metabolism of arachidonic acid to form products that have been implicated in the airway obstruction of asthma. We hypothesized that if products of the 5-lipoxygenase pathway are important in mediating this obstruction, then prevention of their formation should decrease the severity of an induced asthmatic response. METHODS In a randomized, double-blind, placebo-controlled, crossover study, we examined the effect of A-64077, a 5-lipoxygenase inhibitor, on the bronchoconstriction induced by hyperventilation of cold, dry air in 13 patients with asthma. The completeness of 5-lipoxygenase inhibition was confirmed by examining the profile of eicosanoids produced in whole blood ex vivo after activation with the calcium ionophore A-23187. RESULTS A-64077 decreased the mean (+/- SEM) ionophore-induced synthesis of leukotriene B4, a 5-lipoxygenase product, by 74 percent (from 265.3 +/- 30.3 to 69.5 +/- 21.5 ng per milliliter, P less than 0.001), but it did not affect the ionophore-induced synthesis of thromboxane B2, a cyclooxygenase metabolite of arachidonic acid (80.0 +/- 17.1 ng per milliliter before A-64077 vs. 75.8 +/- 14.3 ng per milliliter after A-64077). In concert with the selective inhibition of 5-lipoxygenase by A-64077, the amount of cold, dry air (expressed as respiratory heat exchange) required to reduce the forced expiratory volume in one second by 10 percent was increased by 47 percent after A-64077 (3.0 kJ per minute for placebo vs. 4.4 kJ per minute for A-64077, P less than 0.002). Similar results were obtained when minute ventilation was used as an indicator of outcome (27.5 liters per minute for placebo vs. 39.8 liters per minute for A-64077, P less than 0.005). CONCLUSIONS Selective inhibition of 5-lipoxygenase by A-64077 is associated with a significant amelioration of the asthmatic response to cold, dry air, suggesting that 5-lipoxygenase products are involved in this response. This approach may be useful in the treatment of asthma.

Comparison of Regularly Scheduled with As-Needed Use of Albuterol in Mild Asthma

BACKGROUND Inhaled beta-agonists are the most commonly used treatment for asthma, but data suggest that regularly scheduled use of these agents may have deleterious effect on the control of asthma. We compared the effects of regularly scheduled use of inhaled albuterol with those of albuterol used only as needed in patients with mild chronic, stable asthma. METHODS In a multicenter, double-blind study, we randomly assigned 255 patients with mild asthma to inhale albuterol either on a regular schedule (126 patients) or only as needed (129 patients). The patients were followed for 16 weeks. RESULTS The primary outcome indicator, peak expiratory air flow measured in the morning, did not change significantly during the treatment period in the scheduled (416 liters per minute after the run-in period and 414 liters per minute after the treatment period) or the as-needed (424 liters per minute at both times) treatment groups (P=0.71). There were no significant differences between the two groups in peak flow variability, forced expiratory volume in one second, the number of puffs of supplemental albuterol needed, asthma symptoms, asthma quality-of-life score, or airway responsiveness to methacholine. The statistically significant differences between the groups in evening peak flow and in the short-term bronchodilator response to inhaled albuterol were small and judged to be clinically unimportant. CONCLUSIONS In patients with mild asthma, neither deleterious nor beneficial effects derived from the regular use of inhaled albuterol beyond those derived from use of the drug as needed. Inhaled albuterol should be prescribed for patients with mild asthma on an as-needed basis.

The Effect of Inhibition of 5-Lipoxygenase by Zileuton in Mild-to-Moderate Asthma

Although intermittent episodic airway narrowing occurs in persons with asthma, the biochemical basis of this obstruction has not been elucidated. Nonetheless, inflammatory cells present in the airways of persons with asthma [1, 2] release various substances that narrow airways. Among these are cysteinyl leukotrienes, which are formed from arachidonic acid in part by the enzyme 5-lipoxygenase [3]. The evidence favoring a role for leukotrienes in asthma is that they are produced by various airway cells including eosinophils and mast cells [4, 5], they are potent bronchoconstrictor agonists [6-8], and they can be recovered from biological fluids during asthma attacks [9-11]. Recently, the salutary effects of specific leukotriene-receptor antagonists or synthesis inhibitors in persons with asthma have suggested that interventions in the 5-lipoxygenase pathway may be of therapeutic use in the treatment of asthma [12-20]. These observations are particularly interesting because of the increasing concerns about asthma therapies such as -agonists and theophylline [21-24] and the known toxicity of long-term steroid use [25, 26]. However, the conclusions about the efficacy of these new drugs in persons with asthma largely derive from studies in laboratory-induced, rather than spontaneously occurring, asthma. Because cases of spontaneously occurring asthma may differ from those of laboratory-induced asthma, in mechanism or in response to therapy, we examined the effects of zileuton (N-1-[benzo(b)thien-2-ylethyl]-N-hydroxyurea), an investigational inhibitor of 5-lipoxygenase [27] currently in phase III trials of efficacy, in persons with asthma. In a double-blind, placebo-controlled trial in patients with mild-to-moderate airflow obstruction, we investigated the effects of inhibition of 5-lipoxygenase with zileuton (Leutrol; Abbott Laboratories, North Chicago, Illinois), during a 4-week period, on airway function, asthma symptoms, and the bronchodilator response to -agonists. We found that a dose of 600 mg four times per day (2.4 g/d), which produces more than 35% inhibition of leukotriene production as indicated by excretion of leukotriene E4 (LTE4) in the urine, had a salutary effect on airway function and asthma symptoms. Methods Patient Selection Patients with mild-to-moderate asthma were recruited at 14 centers, which included university hospitals and private allergy and pulmonary practices. Patients with symptoms that corresponded with the American Thoracic Society definition of asthma [28] were screened. All patients had to have a forced expiratory volume in 1 second (FEV1) of 40% to 75% of predicted value and a 15% or greater increase in FEV1 30 minutes after inhalation of two puffs of albuterol. Additionally, patients were required to be 18 to 65 years old; women of childbearing potential were excluded. Before enrollment in the study, none of the patients had used oral or inhaled steroids or cromolyn sodium for 4 weeks. Beta-blockers, calcium-channel blockers, and nonsteroidal anti-inflammatory drugs could not have been used for at least 1 week before entry into the study. All patients were required to be able to achieve adequate symptomatic asthma control without using theophylline, oral -agonists, or antihistamines; none of these medications was permitted throughout the entire study period. Study Design and Intervention A randomized parallel design was used in this double-blind, placebo-controlled study. Patients were chosen randomly to receive either 600 mg of zileuton (four times a day), 800 mg of zileuton (twice a day), or placebo. A 1-week, single-blind, placebo lead-in qualification period (dummy lead-in period) was followed by random allocation to one of the three treatment groups for a 4-week, double-blind phase. During the single-blind, dummy lead-in and the double-blind study periods, all patients took capsules four times a day. Self-determined peak expiratory flow rates were recorded in the morning (before medication) and evening (2 hours after the third set of capsules) in a study diary. Albuterol inhaler use and asthma symptoms were recorded in the diary as well. Daytime asthma symptoms were self-rated on a scale of 1 to 5 (1 = no symptoms, 5 = severe symptoms; maximum weekly score of 35). After the 1-week dummy lead-in period, patients returned to their study center. Inhaled albuterol was withheld for at least 8 hours before the study visit. Spirometry was done on patients who had no clinically significant laboratory abnormalities, who had successfully completed their diary card, who had moderately symptomatic asthma (a total score of 12 but 28 in the previous 7 days), and who had used their albuterol inhaler at least 7 times during the dummy lead-in week. If the FEV1 was 40% to 75% of the predicted value, the patient was assigned randomly to a group according to a predetermined code. All patients took visually identical capsules four times per day that contained either 600 mg of zileuton four times daily, 800 mg of zileuton twice daily (active drug first and last dose daily), or placebo, which were supplied by Abbott Laboratories in a blind manner. The first dose of study medication was administered at the study center, and spirometry was done 30, 60, and 120 minutes later. In the 800-mg group, each days drug card contained both placebo and active drug, and as a result, on the first day, an undetermined number of patients received placebo instead of 800 mg of zileuton as their first dose of drug. Therefore, the 800-mg group was not included in the analysis of the acute response to the first dose of drug. During the 4-week double-blind period, patients returned to the study center at the same time of day on a weekly basis to have spirometry done and to review diary cards and medication use. During the second and third weeks of the double-blind randomization period, spirometry was also repeated 30 minutes after inhalation of two puffs of albuterol. Urine Collection and Analysis Urine was collected for 4 hours beginning at 8:00 a.m. before the dummy lead-in period and on day 28 of the study. Urinary LTE4 levels were determined by reverse-phase high-performance liquid chromatography and enzyme immunoassay using minor modifications of established procedures [29]. The recovery of the internal LTE4 standard was 74% 6%. The LTE4 content of the urine was expressed as picograms of immunoreactive LTE4 per milligram of creatinine. Adverse Events Routine complete blood counts, serum chemistries, urinalyses, and electrocardiograms were obtained throughout the study. Adverse symptoms were elicited daily through a diary question and were reviewed at the weekly visit to the study site. Statistical Analysis All values were expressed as means with associated 95% CIs; all outcome indicators were normally distributed. Paired t-tests were used to assess the statistical significance of any within-group changes from the baseline dummy lead-in phase. The statistical significance of differences among the placebo and active treatment groups during the 4 weeks of double-blind treatment was evaluated using a two-way analysis of variance model with effects for center, treatment, and center-treatment interaction. When statistical differences were noted among groups in the dummy lead-in, the groups were compared using an analysis of covariance adjusting for baseline differences. Available data were analyzed up to the point of withdrawal for patients who did not complete the study protocol. The Fisher test for the protected least significant difference was used to make pair-wise comparisons. Results Patients A total of 188 patients entered the single-blind dummy lead-in period; 143 fulfilled the enrollment criteria and were randomly assigned to receive study drug or placebo (46 patients received 2.4 g/d, 49 patients received 1.6 g/d, and 48 patients received placebo). Two patients withdrew during the first week of the double-blind study1 for personal reasons and the other because of worsening asthma (both received 1.6 g/d of zileuton). Two patients were not included in the final analysis, because they were enrolled in a center that did not have representation in all three treatment groups (1 received 1.6 g/d of zileuton and 1 received placebo). The characteristics of the 139 evaluated patients are given in Table 1. Of the 139 patients who were still in the trial after 1 week, 12 evaluated patients left the study before completing the trial protocol (all their data were included up to the point of termination): 4 patients because of worsening asthma (1 received 2.4 g/d, 2 received 1.6 g/d, and 1 received placebo); 2 patients because of upper respiratory infections (1 received 2.4 g/d and 1 received placebo); 1 patient because of sinusitis (placebo); 1 patient because of urticaria (1.6 g/d); 3 patients because of personal reasons (1 in each group); and 1 patient because of headaches that had begun before randomization (2.4 g/d). Table 1. Characteristics or Evaluated Patients* Acute Effects on Airway Obstruction A single 600-mg dose of zileuton produced rapid bronchodilation (Figure 1). Compared with the mean FEV1 measured just before study drug ingestion (0 minutes), the mean FEV1 improved 30 minutes after a single 600-mg dose of zileuton and remained increased for the entire 2-hour observation period (P < 0.005 for all observation points). The maximum increase (14.6%) in the mean FEV1 was 0.35 L (CI, 0.25 to 0.45 L) (P < 0.001), which occurred at 60 minutes. No improvement of the FEV1 occurred in the placebo group (0.09 L [CI, 0.01 to 0.19 L]; P = 0.075). The improvement in the mean FEV1 after zileuton was greater than that after placebo at 60 and 120 minutes (P < 0.001 and P = 0.01, respectively). Figure 1. Change in the forced expiratory volume during the 2 hours after administration of zileuton or placebo. P P P Effects of 4 Weeks of Zileuton Administration on Airway Obstruction All three groups of patients had an initial impr

Human immunodeficiency virus infection among patients attending clinics for sexually transmitted diseases

To assess the prevalence and associated risk factors for human immunodeficiency virus (HIV) infection in patients attending inner-city clinics for sexually transmitted diseases in Baltimore, we screened 4028 patients anonymously, of whom 209 (5.2 percent) were seropositive for HIV. HIV-seropositivity rates were higher among men (6.3 percent) than women (3.0 percent) (P less than 0.001) and among blacks (5.0 percent) than whites (1.2 percent) (P less than 0.02). Among men, but not women, HIV seroprevalence increased markedly and steadily up to the age of 40. In men, HIV seropositivity was independently associated with increased age, black race, a history of homosexual contact, and the use of parenteral drugs. In women, a history of parenteral drug use or of being a sexual partner of a bisexual man or parenteral drug user were independently predictive of HIV seropositivity. In men, HIV seropositivity was also associated with a history of syphilis or a reactive serologic test for syphilis, and in women, with a history of genital warts. Since these associations were independent of the type and number of reported sexual partners, they raise the possibility that sexually transmitted diseases that disrupt epithelial surfaces may be important in the transmissibility of HIV. In addition, on a self-administered questionnaire, one third of HIV-infected men and one half of infected women did not acknowledge previous high-risk behavior for HIV exposure. These data suggest that patients at clinics for sexually transmitted diseases represent a group at high risk for HIV infection, and that screening, counseling, and intensive education should be offered to all patients attending such clinics.

Interleukin-17–producing innate lymphoid cells and the NLRP3 inflammasome facilitate obesity-associated airway hyperreactivity

Obesity is associated with the development of asthma, which is often difficult to control. To understand the immunological pathways that lead to obesity-associated asthma, we fed mice a high-fat diet for 12 weeks, which resulted in obesity and the development of airway hyperreactivity (AHR), a cardinal feature of asthma. This AHR was independent of adaptive immunity, as it occurred in obese Rag1−/− mice, which lack B and T cells, and was dependent on interleukin-17A (IL-17A) and the NLRP3 inflammasome, as it did not develop in obese Il17a−/− or Nlrp3−/− mice. AHR was also associated with the expansion of CCR6+ type 3 innate lymphoid cells (ILCs) producing IL-17A (ILC3 cells) in the lung, which could by themselves mediate AHR when adoptively transferred into Rag2−/−; Il2rg−/− mice treated with recombinant IL-1β. Macrophage-derived IL-1β production was induced by HFD and expanded the number of lung ILC3 cells. Blockade of IL-1β with an IL-1 receptor antagonist abolished obesity-induced AHR and reduced the number of ILC3 cells. As we found ILC3-like cells in the bronchoalveolar lavage fluid of individuals with asthma, we suggest that obesity-associated asthma is facilitated by inflammation mediated by NLRP3, IL-1β and ILC3 cells.