Pharmacogenomic test that predicts response to inhaled corticosteroids in adults with asthma likely to be cost-saving

Cost-effectiveness of Arg16Gly in ADRB2 pharmacogenomic-guided treatment for pediatric asthma

OBJECTIVES

To assess the cost-effectiveness of Arg16Gly ADRB2 pharmacogenomic testing compared with no Arg16Gly ADRB2 testing to guide the use of long-acting β2 receptor agonist (LABA) in asthma patients aged 1 to 5 years in China.

METHODS

This economic evaluation developed a Markov model with four health states (no exacerbation, mild exacerbation, moderate-to-severe exacerbation, and death). Transition probabilities were estimated from the rate of exacerbations, the case-fatality rate of patients hospitalized for exacerbations, and natural mortality. Costs included drug costs and exacerbation management costs. Cost inputs and utilities for each health state were gained from public databases and the literatures. Costs and quality-adjusted life years (QALYs) were estimated for ten years. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In the base case analysis, in contrast to the group without the genotype test, the incremental total cost was -¥334.7, and the incremental QALY was 0.001 in the Arg16Gly ADRB2 genotyping group. Therefore, the Arg16Gly ADRB2 test group was the dominant strategy for children with asthma in China. The sensitivity analyses showed that the model was relatively stable.

CONCLUSION

Arg16Gly ADRB2 testing before using LABA is a cost-effective approach compared with no gene testing for pediatric asthma.

Pharmacogenomics and Pediatric Asthmatic Medications

Asthma is a respiratory condition often stemming from childhood, characterized by difficulty breathing and/or chest tightness. Current treatment options for both adults and children include beta-2 agonists, inhaled corticosteroids (ICS), and leukotriene modifiers (LTM). Despite recommendations by the Global Initiative for Asthma, a substantial number of patients are unresponsive to treatment and unable to control symptoms. Pharmacogenomics have increasingly become the front line of precision medicine, especially with the recent use of candidate gene and genome- wide association studies (GWAS). Screening patients preemptively could likely decrease adverse events and therapeutic failure. However, research in asthma, specifically in pediatrics, has been low. Although numerous adult trials have evaluated the impact of pharmacogenomics and treatment response, the lack of evidence in children has hindered progress towards clinical application. This review aims to discuss the impact of genetic variability and response to asthmatic medications in the pediatric population.

Predictors of response to medications for asthma in pediatric patients: A systematic review of the literature

OBJECTIVES

There has been no systematic review of studies aimed to predict differential responses to medication regimens for asthma controller therapies in pediatric patients. The aim of the present study was to summarize those identifying biomarkers for the different asthma controller therapies.

METHODS

Studies published by June 2019 that report phenotypic or genotypic characteristics or biomarkers that could potentially serve as response predictors to asthma controller therapies in pediatric patients were included. The quality of studies was assessed using the Cochrane Risk of Bias tool and the Newcastle-Ottawa Scale tool.

RESULTS

Of 385 trials identified, 30 studies were included. Children with asthma and a positive family history of asthma, with more severe disease, of the white race, with allergy biomarkers, nonobese, with lower lung function, high bronchial hyperresponsiveness to methacholine, or having variants in the FCER2 and CRHR1 gene respond better to inhaled corticosteroids (ICS). Younger age (<10 years), short disease duration (<4 years), high cotinine and urinary leukotriene E4 (LTE4) levels, and 5/5 ALOX5 were associated with a better response to leukotriene receptor antagonist (LTRA). For patients that remain symptomatic, white Hispanics were more likely to respond to LTRA, blacks to ICS, white non-Hispanics to LTRA or LABA, and children without a history of eczema, regardless of race or ethnicity to LABA set-up therapy. In severe persistent asthma, those with atopy and body mass index greater than or equal 25 were more likely to benefit from omalizumab.

CONCLUSION

Several phenotypic characteristics, biomarkers, or pharmacogenomics markers could be useful for predicting the best drug for asthma treatment.

Understanding the genetics of asthma and implications for clinical practice

Asthma is one of the most common heritable diseases globally, with variable clinical expression and response to treatment that is attributed to underlying genetic differences. Hundreds of loci on multiple chromosomes are associated with asthma. Although routine genetic screening is not recommended, testing for medication responsiveness might soon play a role in clinical management. Pharmacogenetic research remains early stage but has demonstrated potential for both clinical and cost effectiveness. Furthermore, recognition of clinically apparent asthma phenotypes, the result of genetic and environmental interactions, can help to inform treatment decisions. Phenotypes are divided into two broad categories of atopic and nonatopic disease, with further subdivisions that are associated with clinical presentation patterns and responsiveness to treatment. In general, earlier onset and allergic disease will respond well to traditional therapy with inhaled corticosteroids (ICSs) and leukotrienes because these medications target inflammatory pathways for allergic disease. However, patients with late-onset, symptom predominant (lacking inflammation), and obese asthma might be resistant to standard therapy and may require treatment modification. These patients are at risk for overuse of ICSs with poor response and may benefit more by use of long-acting beta agonists, long-acting muscarinic agonists, weight reduction, and exercise.

The pharmacogenomics of inhaled corticosteroids and lung function decline in COPD

Inhaled corticosteroids (ICS) are widely prescribed for patients with chronic obstructive pulmonary disease (COPD), yet have variable outcomes and adverse reactions, which may be genetically determined. The primary aim of the study was to identify the genetic determinants for forced expiratory volume in 1 s (FEV₁) changes related to ICS therapy.In the Lung Health Study (LHS)-2, 1116 COPD patients were randomised to the ICS triamcinolone acetonide (n=559) or placebo (n=557) with spirometry performed every 6 months for 3 years. We performed a pharmacogenomic genome-wide association study for the genotype-by-ICS treatment effect on 3 years of FEV₁ changes (estimated as slope) in 802 genotyped LHS-2 participants. Replication was performed in 199 COPD patients randomised to the ICS, fluticasone or placebo.A total of five loci showed genotype-by-ICS interaction at p<5×10^-6; of these, single nucleotide polymorphism (SNP) rs111720447 on chromosome 7 was replicated (discovery p=4.8×10^-6, replication p=5.9×10^-5) with the same direction of interaction effect. ENCODE (Encyclopedia of DNA Elements) data revealed that in glucocorticoid-treated (dexamethasone) A549 alveolar cell line, glucocorticoid receptor binding sites were located near SNP rs111720447. In stratified analyses of LHS-2, genotype at SNP rs111720447 was significantly associated with rate of FEV₁ decline in patients taking ICS (C allele β 56.36 mL·year^-1, 95% CI 29.96-82.76 mL·year^-1) and in patients who were assigned to placebo, although the relationship was weaker and in the opposite direction to that in the ICS group (C allele β -27.57 mL·year^-1, 95% CI -53.27- -1.87 mL·year^-1).The study uncovered genetic factors associated with FEV₁ changes related to ICS in COPD patients, which may provide new insight on the potential biology of steroid responsiveness in COPD.

Pharmacogenetics of asthma: toward precision medicine

PURPOSE OF REVIEW

Although currently available drugs to treat asthma are effective in most patients, a proportion of patients do not respond or experience side-effects; which is partly genetically determined. Pharmacogenetics is the study of how genetic variations influence drug response. In this review, we summarize prior results and recent studies in pharmacogenetics to determine if we can use genetic profiles for personalized treatment of asthma.

RECENT FINDINGS

The field of pharmacogenetics has moved from candidate gene studies in single populations toward genome-wide association studies and meta-analysis of multiple studies. New technologies have been used to enrich results, and an expanding number of genetic loci have been associated with therapeutic responses to asthma drugs. Prospective, genotype-stratified treatment studies have been conducted for β2-agonists, showing attenuated response in children carrying the Arg16 variant in the β2-adrenoreceptor gene.

SUMMARY

Although there has been much progress, many findings have not been replicated and currently known genetic loci only account for a fraction of variability in drug response. More research is necessary to translate into clinical practice. A polygenic predictive approach integrated in complex networks with other 'omics' technologies could aid to achieve this goal. Finally, to change clinical practice, studies that compare precision medicine with traditional medicine are needed.

Economic evaluation of medical tests at the early phases of development: a systematic review of empirical studies

INTRODUCTION

There is little specific guidance on the implementation of cost-effectiveness modelling at the early stage of test development. The aim of this study was to review the literature in this field to examine the methodologies and tools that have been employed to date.

AREAS COVERED

A systematic review to identify relevant studies in established literature databases. Five studies were identified and included for narrative synthesis. These studies revealed that there is no consistent approach in this growing field. The perspective of patients and the potential for value of information (VOI) to provide information on the value of future research is often overlooked. Test accuracy is an essential consideration, with most studies having described and included all possible test results in their analysis, and conducted extensive sensitivity analyses on important parameters. Headroom analysis was considered in some instances but at the early development stage (not the concept stage).

EXPERT COMMENTARY

The techniques available to modellers that can demonstrate the value of conducting further research and product development (i.e. VOI analysis, headroom analysis) should be better utilized. There is the need for concerted efforts to develop rigorous methodology in this growing field to maximize the value and quality of such analysis.

Pharmacogenomic test that predicts response to β2-agonists in adults with asthma is cost effective

BACKGROUND

Pharmacogenomic tests that predict which asthma patients are likely to respond to β₂-agonists hold promise to improve care for asthma.

OBJECTIVE

To identify the clinical and economic circumstances under which a pharmacogenomic test that predicts response to β₂-agonists might or might not be an appropriate, cost-effective option.

METHODS

We synthesized published data on clinical and economic outcomes in adults 18-35 to project 10-year costs, quality-adjusted life years and cost-effectiveness of pharmacogenomic testing for β₂-agonist response.

RESULTS

Pharmacogenomic testing for β₂-agonist response conferred a cost-effectiveness ratio of $13,700 per quality-adjusted life year gained compared with no testing.

CONCLUSION

Pharmacogenomic testing for β₂-agonist response in individuals with asthma is potentially cost effective and should be pursued by test developers.