Effect of beta2-adrenergic receptor polymorphism on response to longacting beta2 agonist in asthma (LARGE trial): a genotype-stratified, randomised, placebo-controlled, crossover trial

Abstract

Background: Some studies suggest that patients with asthma who are homozygous for arginine at the 16th amino acid position of the beta2-adrenergic receptor (B16 Arg/Arg) benefit less from treatment with longacting beta2 agonists and inhaled corticosteroids than do those homozygous for glycine (B16 Gly/Gly). We investigated whether there is a genotype-specific response to treatment with a longacting beta2 agonist in combination with inhaled corticosteroid.

Methods: In this multicentre, randomised, double-blind, placebo-controlled trial, adult patients with moderate asthma were enrolled in pairs matched for forced expiratory volume in 1 s and ethnic origin, according to whether they had the B16 Arg/Arg (n=42) or B16 Gly/Gly (n=45) genotype. Individuals in a matched pair were randomly assigned by computer-generated randomisation sequence to receive inhaled longacting beta2 agonist (salmeterol 50 microg twice a day) or placebo given in a double-blind, crossover design for two 18-week periods. Open-label inhaled corticosteroid (hydrofluoroalkane beclometasone 240 microg twice a day) was given to all participants during the treatment periods. The primary endpoint was morning peak expiratory flow (PEF). Analysis was by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00200967.

Findings: After 18 weeks of treatment, mean morning PEF in Arg/Arg participants was 21.4 L/min (95% CI 11.8-31.1) higher when participants were assigned to receive salmeterol than when assigned to receive placebo (p<0.0001). In Gly/Gly participants, morning PEF was 21.5 L/min (11.0-32.1) higher when participants were assigned to receive salmeterol than when assigned to receive placebo (p<0.0001). The improvement in PEF did not differ between genotypes (difference [Arg/Arg-Gly/Gly] -0.1, -14.4 to 14.2; p=0.99). In Gly/Gly participants, methacholine PC20 (20% reduction in forced expiratory volume in 1 s; a prespecified secondary outcome) was 2.4 times higher when participants were assigned to salmeterol than when assigned to placebo (p<0.0001). Responsiveness to methacholine did not differ between salmeterol and placebo in Arg/Arg participants (p=0.87). The 2.5 times higher genotype-specific difference in responsiveness to methacholine was significant (1.32 doubling dose difference between genotypes, 0.43-2.21, p=0.0038). Seven Arg/Arg participants (placebo, n=5; salmeterol, n=2) and six Gly/Gly participants (placebo, n=3; salmeterol, n=3) had an asthma exacerbation. Five serious adverse events were reported, one each during the pre-match and run-in phases on open-label inhaled corticosteroid, two during double-blind treatment with salmeterol/inhaled corticosteroid, and one during double-blind treatment with placebo/inhaled corticosteroid. None of the serious events was asthma-related or related to study drugs or procedures.

Interpretation: In asthma patients with B16 Arg/Arg and B16 Gly/Gly genotypes, combination treatment with salmeterol and inhaled corticosteroid improved airway function when compared with inhaled corticosteroid therapy alone. These findings suggest that patients should continue to be treated with longacting beta2 agonists plus moderate-dose inhaled corticosteroids irrespective of B16 genotype. Further investigation is needed to establish the importance of the genotype-specific difference in responsiveness to methacholine.

Funding: National Institutes of Health.

Conflict of interest statement

Conflict of Interest:

Dr. Wechsler reports that he has consulted for or participated in advisory boards or speaker bureaus for AstraZeneca, GlaxoSmithKline, Schering Plough, Novartis, Genentech, Merck, Medicinova and Sepracor. Ms. Kunselman reports no conflicts. Dr. Chinchilli reports no conflicts. Dr. Bleecker reports serving as a consultant, giving presentations and performing clinical trials which were administered by Wake Forest University Health Sciences for AstraZeneca, GlaxoSmithKline and Novartis. Dr. Boushey reports research project support from GlaxoSmithKline, participating on a scientific advisory committee for GlaxoSmithKline; ad-hoc consulting for Altana, Boehringer-Ingelheim, Genentech, Nanomix, Novartis, Sumitomo, Theravance and Watermark Research; and honoraria for lectures and presentations from Merck, Novartis, Sanofi-Aventis and Genentech. Dr. Calhoun reports no conflicts. Dr. Ameredes reports no conflicts. Dr. Castro reports no conflicts. Dr. Craig reports performing research with Schering, Merck, GlaxoSmithKline, Boehringer-Ingelheim, Altana, Genentech/Novartis, and Forrest; grants for investigator initiated research from Viropharma, CSL Mehring, GlaxoSmithKline and Merck; honorarium for consultative services from Teva, Alcon, Novartis, Genentech, Dyax, CSL Behring, Viropharma, Shire and Pharming; and honorarium for speaking from Teva Schering, Merck, Astra Zeneca, S. Aventis, Genentech and Novartis. Dr. Denlinger reports no conflicts. Dr. Fahy reports providing consulting services for Abgenix, Aerovance, Amira, Biogen, Cytokinetics, Gilead, Merck, Oxagen and Roche. Dr. Jarjour reports receiving advisory board honorarium and clinical trial support from GlaxoSmithKline; consulting fees from Asthmatx; advisory board compensation, lecture honorarium and clinical trial support from Genentech-Novartis; trial support from MedImmune; and clinical trial support and lecture honorarium from Merck. Dr. Kazani reports no conflicts. Dr. Kim reports no conflicts. Dr. Kraft reports speaker’s bureau for GlaxoSmithKline; advisory board/consultantion for GlaxoSmithKline, Merck, Novartis and Amira; and research funding from GlaxoSmithKline, Bronchus, GE Healthcare, Asthmatx, Novartis and Genentech. Dr. Lazarus reports no conflicts. Dr Lemanske reports receiving speaker honorarium from Merck, Astra Zeneca, Medicus Group, Park Nicolet Institute; consultant honorarium from Astra Zeneca, MAP Pharmaceuticals, Gray Consulting, Smith Research, Merck Childhood Asthma Network, Novartis, Quintiles/ANOVAs and Rchorowitz & Co.; and serving as an author of Up-to-Date. Dr. Markezich reports no conflicts. Dr. Martin reports conflicts with GlaxoSmithKline, Merck, Genentech, Novartis, Altana and Teva. Dr. Permaul reports no conflicts. Dr. Peters reports pharmaceutical trial support as a member of the Wake forest University Clinical Trials Group sponsored by Abaris, Amgen, Altana, Boehringer-Ingelheim, Contocor, Genentech, GlaxoSmithKline, Medimmune, Novartis, Pfizer, Schering and Wyeth; consulting under the auspices of Adelphi, Exocrine, AstraZeneca, Bristol-Meyers Squibb, Ception Therapeutics, Dey, Dyson, Genentech, Johnson & Johnson, Merck, Novartis, RAD Foundation, Respiratory Medicine, Respiratory Research, Sepracor and Teva; and participating in Physician Education Programs sponsored by AdvanceMed, AstraZeneca, Creative Educational Concepts, DIME, Merck Pharmaceuticals, Genentech, Novartis, Practicome, Pri-Med/SCIOS, Respiratory and Allergic Disease (RAD) Foundation, and UpToDate. Dr. Ramsdell reports no conflicts. Dr. Sorkness reports receiving honorarium for Speaker’s bureau and consultation from GlaxoSmithKline; and receiving research support from Pharmaxis and Schering. Dr. Sutherland reports serving as an advisor or consultant to Dey, GlaxoSmithKline and Schering-Plough; and receiving grant funding from Boehringer-Ingelheim, Dey, GlaxoSmithKline, and Novartis. Dr. Szefler reports serving as a consultant for GlaxoSmithKline, Genentech and Merck; and research funding from Ross and GlaxoSmithKline. Dr. Walter reports no conflicts. Dr. Wasserman reports grant support from Merck and Schering-Plough; and serving as a consultant for Amylin. Dr. Israel reports participating in a funded clinical research trial and serving as a consultant with GlaxoSmithKline; participating in a funded clinical research trial with Boehringer Ingelheim; participating in a funded clinical research trial, serving as a consultant, and receiving Speaker’s fees from Novarits; and attending a Speaker’s symposium and serving as a consultant for AstraZeneca.

Figures

Figure 1. LARGE study design

Following screening and genotyping, genotype-eligible and matched subjects who received 8 weeks of ICS during the run-in were randomized to continue ICS with either LABA or placebo for 18 weeks, followed by an 8 week runout period on ICS alone, followed by the alternate treatment.

Figure 2. Fate of 474 screened subjects in LARGE trial

42 B16 Arg/Arg individuals and 45 B16 Gly/Gly individuals were randomized to receive 1 of 2 sequential treatment regimens consisting of ICS with either LABA or placebo.

Figure 3

Figure 3A. AM PEF in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA. Both groups of subjects ended up with a higher AM PEF with LABA/ICS than with Placebo/ICS, but there was no significant difference between the two groups. Bars represent 95% confidence limits about the mean. Figure 3B. AM PEF in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA from beginning to end of 18 week treatment periods (Modeled data= thick lines, Raw data = thin lines). Modeled data account for repeated measurements within subject. P-values are shown for the 18-week comparison within genotype. There was no significant difference between the two genotype groups (p=0.99).

Figure 3

Figure 3A. AM PEF in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA. Both groups of subjects ended up with a higher AM PEF with LABA/ICS than with Placebo/ICS, but there was no significant difference between the two groups. Bars represent 95% confidence limits about the mean. Figure 3B. AM PEF in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA from beginning to end of 18 week treatment periods (Modeled data= thick lines, Raw data = thin lines). Modeled data account for repeated measurements within subject. P-values are shown for the 18-week comparison within genotype. There was no significant difference between the two genotype groups (p=0.99).

Figure 4

Figure 4a. Methacholine responsiveness in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA. While B16 Gly/Gly subjects demonstrated a doubling of their methacholine PC20 with salmeterol compared with placebo (P<0.0001), B16 Arg/Arg subjects derived no such benefit. This genotype specific difference was significant (p=0.0038). Data were log transformed for analysis. Bars represent back-transformed 95% confidence intervals about the geometric mean. Figure 4b. Individual raw data for the doubling dilution difference in methacholine PC20 , comparing LABA/ICS to Placebo/ICS at the end of each treatment period for B16 Arg/Arg and B16 Gly/Gly subjects. Mean values are depicted as horizontal lines. 71% of Gly/Gly subjects had an improved PC20 vs. 56% of Arg/Arg subjects.

Figure 4

Figure 4a. Methacholine responsiveness in B16 Arg/Arg subjects and B16 Gly/Gly subjects receiving ICS with placebo or LABA. While B16 Gly/Gly subjects demonstrated a doubling of their methacholine PC20 with salmeterol compared with placebo (P<0.0001), B16 Arg/Arg subjects derived no such benefit. This genotype specific difference was significant (p=0.0038). Data were log transformed for analysis. Bars represent back-transformed 95% confidence intervals about the geometric mean. Figure 4b. Individual raw data for the doubling dilution difference in methacholine PC20 , comparing LABA/ICS to Placebo/ICS at the end of each treatment period for B16 Arg/Arg and B16 Gly/Gly subjects. Mean values are depicted as horizontal lines. 71% of Gly/Gly subjects had an improved PC20 vs. 56% of Arg/Arg subjects.

Figure 5

AM and PM PEF in the 9 African American B16 Arg/Arg and the 8 B16 Gly/Gly subjects receiving ICS with placebo or LABA. African American B16 Gly/Gly subjects ended up with a higher AM PEF with LABA/ICS than with Placebo /ICS; this was not observed with African American B16 Arg/Arg subjects. Bars represent 95% confidence intervals about the mean.