Asthma is a common chronic illness in children and young people. It affects, for example, an average of two children in every UK classroom. Initial treatment usually consists of salbutamol used on demand at step 1 of British Thoracic Society (BTS) guidelines. At step 2, regular anti-inflammatory 'controller' therapy starts with the regular use of inhaled corticosteroids such as beclomethasone. Therapeutic efficacy with inhaled steroids usually peaks around 400 micrograms per day of beclomethasone (or equivalent). With inadequate asthma control at step 2, inhaled long-acting β2 agonists (LABA) such as salmeterol, or leukotriene receptor antagonists (LTRA) such as montelukast are added or inhaled corticosteroids are increased; this represents BTS step 3 for asthma management.
Overall, in children with asthma managed on step 3, salmeterol appears to provide better asthma control than montelukast in the setting of a randomized controlled trial. However, in real life, the efficacy of salmeterol at step 3 for improving asthma control in individual children appears rather variable, and some children continue to experience day-to-day symptoms and exacerbations.
In this study of 1182 UK children and young adults (4-22 years), 50% of those on regular salmeterol experienced asthma exacerbations over a 6-month period, and 18% required inhaled salbutamol at least daily for symptom relief. Indeed, the investigators reported a step-wise increase in the risk of asthma attacks related to each copy of the Arg16 allele on the β2 receptor gene (1.7-fold) in asthmatic children and young adults exposed to regular salmeterol in conjunction with inhaled corticosteroids. This led the investigators to hypothesize that, contrary to the observations on the overall population of children and young adults where salmeterol is superior in efficacy to montelukast at step 3, those possessing susceptible Arg16 β2 receptor genotype may experience better asthma control with the addition of montelukast rather than salmeterol as second-line controller medication, in addition to inhaled corticosteroids. As such the investigators elected to identify from the database those children with two copies of the Arg16 polymorphism \[i.e. homozygous Arg genotype (∼15% of overall population) who would potentially be at greatest risk\]. The mechanism for worse control with regular salmeterol involves a greater susceptibility to agonist-induced down-regulation and uncoupling of airway β2 receptors and associated sub-sensitivity of response in the Arg16 genotype.
The investigators therefore performed a proof-of-concept randomized controlled trial to determine whether genetically susceptible children with homozygous Arg16 genotype experience superior long-term asthma control with montelukast compared with salmeterol when used as tailored second-line controller therapy as add-on to the inhaled steroid fluticasone. The purpose of this preliminary study was to provide evidence to support the potential for personalised medicine based on the individual genotype to improve asthma-related quality-of-life and control. This study was published in 2013, and represents the first prospective randomized controlled study in children with asthma that addresses personalised medicine based on genotype. The results of this study showed that in children expressing the homozygous Arg 16 genotype, in comparison with salmeterol, adding montelukast to inhaled fluticasone significantly improved asthma-related quality-of-life and clinical symptoms, while reducing school absences and inhaled reliever use. The relative benefits of montelukast in comparison with salmeterol became evident within the first 3 months and persisted throughout the whole year.
Subsequently, the investigators used Pubmed to search the Medline database for other randomised controlled trials comparing the effects of salmeterol (or other long-acting beta2 agonist) with montelukast (or other leukotriene antagonist) within the context of Arg/Gly variation, in children with asthma. No studies could be identified. In particular, there are no trials in either adults or children that have studied quality-of-life, which is a key outcome of interest in the context of asthma-related disability, and which is often unrelated to outcomes such as lung function. This led to the development of the Personalised Medicine for Asthma Control (PACT)-study, a randomised controlled trial to determine if personalised medicine improves quality of life and asthma control in 12-18 years olds. Results of this trial when published, will provide more conclusive evidence as to the effectiveness of personalised medicine in this age group. However, there is an absence of trials in a younger age group of children with asthma (5-11 years) and no evidence to determine if a personalised medicine clinic is feasible within a hospital setting, which underscores the need for this study.
There is an absence of trials in a younger age group of children with asthma (5-11 years) and no evidence to determine if a personalised medicine clinic is feasible within a hospital setting and this underscores the need for this study.
This research proposes two stages of work and has two main objectives:
1. Feasibility study: Conduct a feasibility study to determine important parameters (standard deviation of outcomes, recruitment and retention) to inform the design of a definitive randomised controlled trial
Research questions:
1. Are children with asthma and their parents willing to be recruited and randomised to a trial of genotyping and personalised management for asthma?
2. Are there retention issues? If yes, at what stages did these occur? What were the reasons?
3. Are follow-up data complete?
4. Can the intervention (genotyping plus medication) be delivered with sufficient fidelity?
5. Is there sufficient evidence for scaling up to a definitive randomised controlled trial?
6. What sample size is needed to power a full scale randomised controlled trial?
7. Are there any safety issues or adverse events?
8. What are the associated costs of running a personalised asthma clinic and is it cost effective?
2. Qualitative aspect: Assess the acceptability of a personalised asthma clinic for children with asthma
Research questions:
1. How acceptable do children with asthma and their parents find genotyping and the personalised approach? How does this compare with their views on acceptability of conventional clinics?
2. Was there any aspect of genotyping and personalised medicine clinic which children with asthma and their parents thought was particularly good or worked well?
3. Was there any aspect of genotyping and personalised medicine clinic which children with asthma and their parents thought was particularly bad or difficult?
4. How satisfied were children with asthma and their parents with the genotyping and personalised medicine clinic?
5. How did the genotyping and personalised medicine clinic differ from usual care?
6. What would encourage other children with asthma and their parents to participate in a genotyping and personalised medicine clinic?
7. What would participants change about the personalised clinic?
8. How has the genotyping and personalised medicine clinic impacted on the child and their parent?
9. Were there any outcomes which weren't measured which should have been?
10. What did the health professionals involved think about the clinic? (in primary and secondary care)
Two arm, randomised controlled feasibility trial of genotyping and personalised medicine versus usual care with qualitative aspect to assess acceptability and impact.
The genotyping and personalised medicine clinic is based in the Royal Alexandra Children's Hospital in Brighton, England. Participants are referred to the research team by their health care professional (primary and secondary care).
The intervention and follow up period will last 4 months per participant. Outcomes will be measured at baseline and 3-months.
