Acute and chronic lung function responses to salmeterol and salmeterol plus fluticasone propionate in relation to Arg16Gly beta(2)-adrenergic polymorphisms

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.

ADRB2 Arg16Gly Polymorphism and Pulmonary Function Response of Inhaled Corticosteroids plus Long-Acting Beta Agonists for Asthma Treatment: A Systematic Review and Meta-Analysis

Background

The beta-2 adrenergic receptor (ADRB2) Arg16Gly polymorphism may alter the bronchodilation response to long-acting beta2-agonists, thereby influencing the clinical effectiveness of LABAs plus corticosteroids (ICS) treatment. But the results of individual studies are inconclusive.

Methods

A systematic search was conducted in PubMed, Embase, the Cochrane Database, WHO International Clinical Trials Registry Platform, Chinese National Knowledge Infrastructure, Wanfang, Chinese BioMedical Literature Database, and VIP databases. The meta-analysis was performed with RevMan statistical software (version 5.2), and potential publication bias was estimated by Egger's test using STATA (version 12.0), with p < 0.05 indicating significant publication bias.

Results

We found 5 cohort studies with a total of 632 patients and included them in the meta-analysis. There are no significant differences in pulmonary function response between patients with the Arg/Arg and Arg/Gly phenotype (SMD -0.04, 95% CI -0.45 to 0.37; p=0.84). There were also no significant differences in the pulmonary function response between patients with the Arg/Arg and Gly/Gly phenotype (MD -0.03, 95% CI -0.07 to 0.02; p=0.28).

Conclusions

Our systematic review and meta-analysis suggest that ADRB2 Arg16Gly polymorphism is not associated with pulmonary response to asthma treatment with ICS plus LABAs.

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.

Treatment of persistent asthma with Symbicort (budesonide/formoterol inhalation aerosol): an inhaled corticosteroid and long-acting beta2-adrenergic agonist in one pressurized metered-dose inhaler

OBJECTIVE

Budesonide/formoterol inhalation aerosol (Symbicort AstraZeneca, Wilmington, Delaware) is an inhaled corticosteroid (ICS) and long-acting beta(2)-adrenergic agonist (LABA) combination administered twice daily via one hydrofluoroalkane pressurized metered-dose inhaler (pMDI) approved in the United States for the long-term maintenance treatment of persistent asthma in patients >or=12 years of age whose asthma cannot be controlled by an ICS alone. The objective was to review efficacy, safety, and pharmacogenetic data on budesonide/formoterol pMDI in the treatment of persistent asthma.

METHODS

The authors searched PubMed and respiratory meeting databases to identify asthma studies of budesonide/formoterol pMDI. Studies involving traditional and patient-reported outcomes, safety, tolerability, or pharmacogenetics were included.

RESULTS

In two 12-week pivotal trials in adolescents and adults, treatment with budesonide/formoterol pMDI 160/4.5 microg x 2 inhalations (320/9 microg) twice daily for moderate to severe persistent asthma or 80/4.5 microg x 2 inhalations (160/9 microg) twice daily for mild to moderate persistent asthma, demonstrated greater efficacy and similar tolerability compared with placebo and the same nominal dose of its monocomponents. Comparisons with formoterol dry powder inhaler (DPI) for predose forced expiratory volume in one second (FEV(1)) and with budesonide pMDI for 12-hour mean postdose FEV(1) demonstrated the anti-inflammatory and bronchodilatory contributions of budesonide and formoterol, respectively. Evaluations of patient-reported outcomes, including asthma-specific quality of life and treatment satisfaction, further supported the clinical benefits of budesonide/formoterol pMDI. In a 52-week tolerability study of patients aged >or=12 years, budesonide/formoterol pMDI was delivered at up to double the maximum dose (640/18 microg twice daily) and demonstrated a safety profile similar to that of budesonide (640 microg twice daily), with no unexpected pattern of abnormalities. Additional studies reported that budesonide/formoterol pMDI 320/9 microg twice daily and fluticasone propionate/salmeterol DPI 250/50 microg twice daily have similar efficacy and tolerability, with significantly more patients achieving >or=15% improvement in FEV(1) within 15 minutes with budesonide/formoterol pMDI compared with fluticasone/salmeterol DPI. Moreover, inheritance of the Gly16Arg polymorphism of the beta(2)-adrenergic receptor does not appear to affect clinical outcomes with budesonide/formoterol pMDI.

CONCLUSION

Budesonide/formoterol pMDI administered twice daily is effective and generally well tolerated in patients whose asthma is not well controlled on ICS alone.