Effect of β2-adrenergic receptor gene (ADRB2) 3' untranslated region polymorphisms on inhaled corticosteroid/long-acting β2-adrenergic agonist response

Regular treatment with formoterol and an inhaled corticosteroid versus regular treatment with salmeterol and an inhaled corticosteroid for chronic asthma: serious adverse events

BACKGROUND

Asthma is characterised by chronic inflammation of the airways and recurrent exacerbations with wheezing, chest tightness, and cough. Treatment with inhaled steroids and bronchodilators can result in good control of symptoms, prevention of further morbidity, and improved quality of life. However, an increase in serious adverse events with the use of both regular formoterol and regular salmeterol (long-acting beta₂-agonists) compared with placebo for chronic asthma has been demonstrated in previous Cochrane Reviews. This increase was statistically significant in trials that did not randomise participants to an inhaled corticosteroid, but not when formoterol or salmeterol was combined with an inhaled corticosteroid. The confidence intervals were found to be too wide to ensure that the addition of an inhaled corticosteroid renders regular long-acting beta₂-agonists completely safe; few participants and insufficient serious adverse events in these trials precluded a definitive decision about the safety of combination treatments.

OBJECTIVES

To assess risks of mortality and non-fatal serious adverse events in trials that have randomised patients with chronic asthma to regular formoterol and an inhaled corticosteroid versus regular salmeterol and an inhaled corticosteroid.

SEARCH METHODS

We searched the Cochrane Airways Register of Trials, CENTRAL, MEDLINE, Embase, and two trial registries to identify reports of randomised trials for inclusion. We checked manufacturers' websites and clinical trial registers for unpublished trial data, as well as Food and Drug Administration (FDA) submissions in relation to formoterol and salmeterol. The date of the most recent search was  24 February 2021.

SELECTION CRITERIA

We included controlled clinical trials with a parallel design, recruiting patients of any age and severity of asthma, if they randomised patients to treatment with regular formoterol versus regular salmeterol (each with a randomised inhaled corticosteroid) and were of at least 12 weeks' duration.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion in the review, extracted outcome data from published papers and trial registries, and applied GRADE rating for the results. We sought unpublished data on mortality and serious adverse events from study sponsors and authors. The primary outcomes were all cause mortality and non-fatal serious adverse events. We chose not to calculate an average result from all the formulations of formoterol and inhaled steroid, as the doses and delivery devices are too diverse to assume a single class effect.

MAIN RESULTS

Twenty-one studies in 11,572 adults and adolescents and two studies in 723 children met the eligibility criteria of the review. No data were available for two studies; therefore these were not included in the analysis. Among adult and adolescent studies, seven compared formoterol and budesonide to salmeterol and fluticasone (N = 7764), six compared formoterol and beclomethasone to salmeterol and fluticasone (N = 1923), two compared formoterol and mometasone to salmeterol and fluticasone (N = 1126), two compared formoterol and fluticasone to salmeterol and fluticasone (N = 790), and one compared formoterol and budesonide to salmeterol and budesonide (N = 229). In total, five deaths were reported among adults, none of which was thought to be related to asthma. The certainty of evidence for all-cause mortality was low, as there were not enough deaths to permit any precise conclusions regarding the risk of mortality on combination formoterol versus combination salmeterol. In all, 201 adults reported non-fatal serious adverse events. In studies comparing formoterol and budesonide to salmeterol and fluticasone, there were 77 in the formoterol arm and 68 in the salmeterol arm (Peto odds ratio (OR) 1.14, 95% confidence interval (CI) 0.82 to 1.59; 5935 participants, 7 studies; moderate-certainty evidence). In the formoterol and beclomethasone studies, there were 12 adults in the formoterol arm and 13 in the salmeterol arm with events (Peto OR 0.94, 95% CI 0.43 to 2.08; 1941 participants, 6 studies; moderate-certainty evidence). In the formoterol and mometasone studies, there were 18 in the formoterol arm and 11 in the salmeterol arm (Peto OR 1.02, 95% CI 0.47 to 2.20; 1126 participants, 2 studies; moderate-certainty evidence). One adult in the formoterol and fluticasone studies in the salmeterol arm experienced an event (Peto OR 0.05, 95% CI 0.00 to 3.10; 293 participants, 2 studies; low-certainty evidence). Another adult in the formoterol and budesonide compared to salmeterol and budesonide study in the formoterol arm had an event (Peto OR 7.45, 95% CI 0.15 to 375.68; 229 participants, 1 study; low-certainty evidence). Only 46 adults were reported to have experienced asthma-related serious adverse events. The certainty of the evidence was low to very low due to the small number of events and the absence of independent assessment of causation. The two studies in children compared formoterol and fluticasone to salmeterol and fluticasone. No deaths and no asthma-related serious adverse events were reported in these studies. Four all-cause serious adverse events were reported: three in the formoterol arm, and one in the salmeterol arm (Peto OR 2.72, 95% CI 0.38 to 19.46; 548 participants, 2 studies; low-certainty evidence).

AUTHORS' CONCLUSIONS

Overall, for both adults and children, evidence is insufficient to show whether regular formoterol in combination with budesonide, beclomethasone, fluticasone, or mometasone has a different safety profile from salmeterol in combination with fluticasone or budesonide. Five deaths of any cause were reported across all studies and no deaths from asthma; this information is insufficient to permit any firm conclusions about the relative risks of mortality on combination formoterol in comparison to combination salmeterol inhalers. Evidence on all-cause non-fatal serious adverse events indicates that there is probably little to no difference between formoterol/budesonide and salmeterol/fluticasone inhalers. However events for the other formoterol combination inhalers were too few to allow conclusions. Only 46 non-fatal serious adverse events were thought to be asthma related; this small number in addition to the absence of independent outcome assessment means that we have very low confidence for this outcome. We found no evidence of safety issues that would affect the choice between salmeterol and formoterol combination inhalers used for regular maintenance therapy by adults and children with asthma.

Association between ADRB2, IL33, and IL2RB gene polymorphisms and lung cancer risk in a Chinese Han population

PURPOSE

This study aimed to explore the associations between polymorphisms of a very important pharmacogene, ADRB2, two inflammation-related genes, IL33 and IL2RB, and the risk of lung cancer.

METHODS

Six polymorphisms of ADRB2, IL33, and IL2RB were genotyped in 300 lung cancer patients and 300 healthy controls using MassARRAY. The relationship between genotypes and lung cancer risk was evaluated using chi-square tests.

RESULTS

The minor allele of rs1042711 was a risk allele for lung cancer, whereas the minor alleles of rs7025417 and rs5756523 had protective effects against lung cancer (p＜0.05). The CT genotype of rs1042711 and the GT genotype of rs1560642 were associated with increased risk of lung cancer, whereas the CC and AA genotypes of rs7025417 and the CT and CC genotypes of rs5756523 were associated with decreased disease risk (p < 0.05). Genetic model analysis shows that rs1042711 and rs1560642 were associated with increased risk of lung cancer; whereas rs7025417, rs5756523, and rs2284033 were associated with decreased disease risk (p < 0.05). Stratification analysis showed that rs1042711 and rs1560642 were associated with increased risk of lung cancer in nonsmokers and smokers, respectively, whereas rs7025417 and rs5756523 were associated with decreased disease risk in both subgroups (p＜0.05).

CONCLUSION

Our results shed new light on the association between polymorphisms of ADRB2, IL33, and IL2RB and the risk of lung cancer.

Pharmacogenetics of inhaled long-acting beta2-agonists in asthma: A systematic review

BACKGROUND

Long-acting beta2-agonists (LABA) are recommended in asthma therapy; however, not all asthma patients respond well to LABA. We performed a systematic review on genetic variants associated with LABA response in patients with asthma.

METHODS

Articles published until April 2017 were searched by two authors using PubMed and EMBASE. Pharmacogenetic studies in patients with asthma and LABA response as an outcome were included.

RESULTS

In total, 33 studies were included in this systematic review; eight focused on children (n = 6051). Nineteen studies were clinical trials, while 14 were observational studies. Studies used different outcomes to define LABA response, for example, lung function measurements (FEV₁ , PEF, MMEF, FVC), exacerbations, quality of life, and asthma symptoms. Most studies (n = 30) focused on the ADRB2 gene, encoding the beta2-adrenergic receptor. Thirty studies (n = 14 874) addressed ADRB2 rs1042713, 7 ADRB2 rs1042714 (n = 1629), and 3 ADRB2 rs1800888 (n = 1892). The association of ADRB2 rs1042713 and rs1800888 with LABA response heterogeneity was successfully replicated. Other variants were only studied in three studies but not replicated. One study focused on the ADCY9 gene. Five studies and a meta-analysis found an increased risk of exacerbations in pediatrics using LABA carrying one or two A alleles (OR 1.52 [1.17; 1.99]). These results were not confirmed in adults.

CONCLUSIONS

ADRB2 rs1042713 variant is most consistently associated with response to LABA in children but not adults. To assess the clinical value of ADRB2 rs1042713 in children with asthma using LABA, a randomized clinical trial with well-defined outcomes is needed.

Personalized management of asthma exacerbations: lessons from genetic studies

INTRODUCTION

The genetics of severe asthma and asthma exacerbations are distinct from milder forms of asthma. Gene-environmental interactions contribute to the complexity and heterogeneity of severe asthma and asthma exacerbations, and pharmacogenomic studies have also identified genes that affect susceptibility to asthma exacerbations.

AREAS COVERED

Studies on the genetics, gene-environment interactions, and pharmacogenomics of asthma exacerbations are reviewed. Multiple individual genetic variants have been identified to be associated with asthma exacerbations but each genetic polymorphism explains only a fraction of the disease and by itself is not able to translate into clinical practice. Research is shifting from candidate gene studies and genome wide association studies towards more integrative approaches to translate genetic findings into clinical diagnostic and therapeutic tools.

EXPERT COMMENTARY

Integrative approaches combining polygenic or genomic data with multi-omics technologies have the potential to discover new biologic mechanisms and biomarkers for severe asthma and asthma exacerbations. Greater understanding of genomics and underlying biologic pathways will also lead to improved prevention and treatment, lowering costs, morbidity, and mortality. The utilization of genomic testing and personalized medicine may revolutionize asthma management, in particular for patients with severe, refractory asthma.

Pooled Sequencing of Candidate Genes Implicates Rare Variants in the Development of Asthma Following Severe RSV Bronchiolitis in Infancy

Severe infection with respiratory syncytial virus (RSV) during infancy is strongly associated with the development of asthma. To identify genetic variation that contributes to asthma following severe RSV bronchiolitis during infancy, we sequenced the coding exons of 131 asthma candidate genes in 182 European and African American children with severe RSV bronchiolitis in infancy using anonymous pools for variant discovery, and then directly genotyped a set of 190 nonsynonymous variants. Association testing was performed for physician-diagnosed asthma before the 7^th birthday (asthma) using genotypes from 6,500 individuals from the Exome Sequencing Project (ESP) as controls to gain statistical power. In addition, among patients with severe RSV bronchiolitis during infancy, we examined genetic associations with asthma, active asthma, persistent wheeze, and bronchial hyperreactivity (methacholine PC₂₀) at age 6 years. We identified four rare nonsynonymous variants that were significantly associated with asthma following severe RSV bronchiolitis, including single variants in ADRB2, FLG and NCAM1 in European Americans (p = 4.6x10^-4, 1.9x10^-13 and 5.0x10^-5, respectively), and NOS1 in African Americans (p = 2.3x10^-11). One of the variants was a highly functional nonsynonymous variant in ADRB2 (rs1800888), which was also nominally associated with asthma (p = 0.027) and active asthma (p = 0.013) among European Americans with severe RSV bronchiolitis without including the ESP. Our results suggest that rare nonsynonymous variants contribute to the development of asthma following severe RSV bronchiolitis in infancy, notably in ADRB2. Additional studies are required to explore the role of rare variants in the etiology of asthma and asthma-related traits following severe RSV bronchiolitis.

Pharmacogenomics of long-acting β2-agonists

INTRODUCTION

Long-acting β2-agonists are an effective class of drugs, when combined with inhaled corticosteroids, for reducing symptoms and exacerbations in patients with asthma that is not adequately controlled by inhaled corticosteroids alone. However, because this class of drugs has been associated with severe adverse events, including hospitalization and death in small numbers of patients, efforts to identify a pharmacogenetic profile for patients at risk has been diligently investigated.

AREAS COVERED

The PubMed search engine of the National Library of Medicine was used to identify English-language and non-English language articles published from 1947 to March 2015 pertinent to asthma, pharmacogenomics, and long-acting β2-agonists. Keywords and topics included: asthma, asthma control, long-acting β2-agonists, salmeterol, formoterol, pharmacogenetics, and pharmacogenomics. This strategy was also used for the Cochrane Library Database and CINAHL. Reference types were randomized controlled trials, reviews, and editorials. Additional publications were culled from reference lists. The publications were reviewed by the authors and those most relevant were used to support the topics covered in this review.

EXPERT OPINION

Children, who carry the ADRB2 Arg16Arg genotype, may be at greater risk than adults for severe adverse events. Rare ADRB2 variants appear to provide better clues for identifying the at-risk population of asthmatics.

CMTR1 is associated with increased asthma exacerbations in patients taking inhaled corticosteroids

Inhaled corticosteroids (ICS) are the most effective controller medications for asthma, and variability in ICS response is associated with genetic variation. Despite ICS treatment, some patients with poor asthma control experience severe asthma exacerbations, defined as a hospitalization or emergency room visit. We hypothesized that some individuals may be at increased risk of asthma exacerbations, despite ICS use, due to genetic factors. A GWAS of 237,726 common, independent markers was conducted in 806 Caucasian asthmatic patients from two population-based biobanks: BioVU, at Vanderbilt University Medical Center (VUMC) in Tennessee (369 patients), and Personalized Medicine Research Project (PMRP) at the Marshfield Clinic in Wisconsin (437 patients). Using a case-control study design, the association of each SNP locus with the outcome of asthma exacerbations (defined as asthma-related emergency department visits or hospitalizations concurrent with oral corticosteroid use), was evaluated for each population by logistic regression analysis, adjusting for age, gender and the first four principal components. A meta-analysis of the results was conducted. Validation of expression of selected candidate genes was determined by evaluating an independent microarray expression data set. Our study identified six novel SNPs associated with differential risk of asthma exacerbations (P < 10(-05)). The top GWAS result, rs2395672 in CMTR1, was associated with an increased risk of exacerbations in both populations (OR = 1.07, 95% CI 1.03-1.11; joint P = 2.3 × 10(-06)). Two SNPs (rs2395672 and rs279728) were associated with increased risk of exacerbations, while the remaining four SNPs (rs4271056, rs6467778, rs2691529, and rs9303988) were associated with decreased risk. Three SNPs (rs2395672, rs6467778, and rs2691529) were present in three genes: CMTR1, TRIM24 and MAGI2. The CMTR1 mRNA transcript was significantly differentially expressed in nasal lavage samples from asthmatics during acute exacerbations, suggesting potential involvement of this gene in the development of this phenotype. We show that genetic variability may contribute to asthma exacerbations in patients taking ICS. Furthermore, our studies implicate CMTR1 as a novel candidate gene with potential roles in the pathogenesis of asthma exacerbations.

Search for β2 adrenergic receptor ligands by virtual screening via grid computing and investigation of binding modes by docking and molecular dynamics simulations

We designed a program called MolGridCal that can be used to screen small molecule database in grid computing on basis of JPPF grid environment. Based on MolGridCal program, we proposed an integrated strategy for virtual screening and binding mode investigation by combining molecular docking, molecular dynamics (MD) simulations and free energy calculations. To test the effectiveness of MolGridCal, we screened potential ligands for β2 adrenergic receptor (β2AR) from a database containing 50,000 small molecules. MolGridCal can not only send tasks to the grid server automatically, but also can distribute tasks using the screensaver function. As for the results of virtual screening, the known agonist BI-167107 of β2AR is ranked among the top 2% of the screened candidates, indicating MolGridCal program can give reasonable results. To further study the binding mode and refine the results of MolGridCal, more accurate docking and scoring methods are used to estimate the binding affinity for the top three molecules (agonist BI-167107, neutral antagonist alprenolol and inverse agonist ICI 118,551). The results indicate agonist BI-167107 has the best binding affinity. MD simulation and free energy calculation are employed to investigate the dynamic interaction mechanism between the ligands and β2AR. The results show that the agonist BI-167107 also has the lowest binding free energy. This study can provide a new way to perform virtual screening effectively through integrating molecular docking based on grid computing, MD simulations and free energy calculations. The source codes of MolGridCal are freely available at http://molgridcal.codeplex.com.

What the Genetic Background of Individuals with Asthma and Obesity Can Reveal: Is β2-Adrenergic Receptor Gene Polymorphism Important?

The goal of this review was to evaluate the association of β2-adrenergic receptor (ADRB2) gene polymorphisms with asthma and obesity. Asthma is the most common pediatric inflammatory disorder. The prevalence, severity, and hospitalization index for asthma have increased markedly in the last several decades. Interestingly, asthma is often diagnosed along with obesity. Genetic factors are essential for both conditions, and some of the candidate pleiotropic genes thought to be involved in the development of these diseases are ADRB2, vitamin D receptor (VDR), leptin (LEP), protein kinase C alpha (PRKCA), and tumor necrosis factor alpha (TNFα). The ADRB2 has been studied in multiple populations and more than 80 polymorphisms, mainly single-nucleotide polymorphisms, have been identified. For nonsynonymous Arg16Gly, Gln27Glu, and Thr164Ile, functional effects have been shown. In vivo, these polymorphisms have been evaluated to determine their association with both obesity and asthma, but the results are inconsistent and depend on the population studied or how the disease was defined. Currently, there are only few reports describing the genetic background for the comorbidity of asthma and obesity.

Do genetic polymorphisms alter patient response to inhaled bronchodilators?

INTRODUCTION

Short- and long-acting β agonists (SABA and LABA) are bronchodilators for treating asthma. Bronchodilator response (BDR) is quantified by measuring air expired in the first second during a forced expiratory maneuver, prior to and following inhalation of SABA. BDR has been associated with a significant degree of heterogeneity, in part attributable to genetic variation. Heritability, the proportion of phenotypic variability accounted for by genetic variation is estimated to account for 50% of pulmonary function and 28.5% for BDR.

AREAS COVERED

A MEDLINE search for English articles published from January 1990 to June 2014 was completed using the terms: bronchodilator, bronchodilator response, short-acting bronchodilator, long-acting bronchodilator, β2 adrenergic receptor gene (ADRB2), asthma and pharmacogenomics. The effects of ADRB2 variants on BDR and the safety of SABA and LABA + inhaled corticosteroids have been studied with equivocal results. Single and candidate gene studies have identified variants in other genes that alter response to bronchodilators. Associations were recently observed between hospital admission rates and two rare ADRB2 polymorphisms: Thr164Ile and a 25 base pair insertion-deletion at nucleotide -376. This was the first report of life-threatening events associated with LABA being linked to rare ADRB2 variants.

EXPERT OPINION

Pharmacogenomic studies over the last two decades clearly demonstrate that polymorphisms alter patient response to bronchodilators in patients with asthma.

Pharmacogenetics: implications of race and ethnicity on defining genetic profiles for personalized medicine

Pharmacogenetics is being used to develop personalized therapies specific to subjects from different ethnic or racial groups. To date, pharmacogenetic studies have been primarily performed in trial cohorts consisting of non-Hispanic white subjects of European descent. A "bottleneck" or collapse of genetic diversity associated with the first human colonization of Europe during the Upper Paleolithic period, followed by the recent mixing of African, European, and Native American ancestries, has resulted in different ethnic groups with varying degrees of genetic diversity. Differences in genetic ancestry might introduce genetic variation, which has the potential to alter the therapeutic efficacy of commonly used asthma therapies, such as β2-adrenergic receptor agonists (β-agonists). Pharmacogenetic studies of admixed ethnic groups have been limited to small candidate gene association studies, of which the best example is the gene coding for the receptor target of β-agonist therapy, the β2-adrenergic receptor (ADRB2). Large consortium-based sequencing studies are using next-generation whole-genome sequencing to provide a diverse genome map of different admixed populations, which can be used for future pharmacogenetic studies. These studies will include candidate gene studies, genome-wide association studies, and whole-genome admixture-based approaches that account for ancestral genetic structure, complex haplotypes, gene-gene interactions, and rare variants to detect and replicate novel pharmacogenetic loci.

Pharmacogenetics and the development of personalized approaches for combination therapy in asthma

Asthma is a common, chronic disease of the airways that is treated with a combination of different therapies. The combination of LABA and ICS therapy results in a synergistic interaction that is efficacious in improving asthma symptom control; however, genetic variation has the potential to alter therapeutic efficacy. Both agents mediate complex molecular pathways consisting of gene variation that has been investigated with the analysis of candidate genes in the β2-adrenergic receptor and glucocorticoid pathway. These pharmacogenetic studies have been limited to retrospective analyses of clinical trial cohorts and a small number of prospective, genotype-stratified trials. More recently, genome-wide association studies in combination with replication in additional cohorts and in vitro cell-based models have been used to identify novel pathway-related pharmacogenetic variations. This review of the pharmacogenetics of the β2-adrenergic receptor and glucocorticoid pathways highlights the genotypic effects of variation in multiple genes from interacting pathways which may contribute to differential responses to inhaled beta agonists and glucocorticoids. As our understanding of these genetic mechanisms improves, panels of biomarkers may be developed to determine which combination therapies are the most effective with the least risk to an individual asthma patient. Before we can usher in an era of personalized medicine for asthma, it is first important to improve our ability to analyze large volumes of genetic data in large clinical trial cohorts using a combination of study designs, analytical methods, and in vitro functional studies.

Asthma pharmacogenetics: responding to the call for a personalized approach

PURPOSE OF REVIEW

Asthma is a chronic, complex disease that is treated with a combination of different therapies. However, interindividual variability in clinical responses to different therapies complicates asthma management. A personalized approach to asthma management could identify appropriate responders to specific agents or those that might be at an increased risk for adverse responses.

RECENT FINDINGS

Pharmacogenetic studies of genes from the leukotriene, glucocorticoid, and beta2-adrenergic receptor pathways have improved our understanding of how gene variation determines therapeutic responses to different classes of antiasthma therapies. Such studies have previously been limited to retrospective analyses of candidate genes in the leukotriene, glucocorticoid, and beta2-adrenergic receptor pathways in trial cohorts. However, prospective genotype-stratified trials in asthma have recently been done and recent genome-wide association studies have identified novel pharmacogenetic loci.

SUMMARY

It will be important to replicate previous genotypic associations in large clinical trial cohorts as future pharmacogenetic studies continue to focus on genome-wide approaches and the study of novel therapeutic pathways. This review of the pharmacogenetics of asthma highlights the contributions of genomics research to the future of personalized medicine in asthma and draws attention to the role of genetic biomarkers in predicting clinical responses to specific therapies.