beta-Adrenergic receptor polymorphisms and response to salmeterol.
BACKGROUND
Several studies suggest that patients with asthma who are homozygous for arginine at the 16th position of the beta2-adrenergic receptor may not benefit from short-acting beta-agonists.


OBJECTIVE
We investigated whether such genotype-specific effects occur when patients are treated with long-acting beta-agonists and whether such effects are modified by concurrent inhaled corticosteroid (ICS) use.


METHODS
We compared salmeterol response in patients with asthma homozygous for arginine at B16 (B16Arg/Arg) with those homozygous for glycine at B16 (B16Gly/Gly) in two separate cohorts. In the first, subjects were randomized to regular therapy with salmeterol while simultaneously discontinuing ICS therapy. In the second, subjects were randomized to regular therapy with salmeterol while continuing concomitant ICS.


RESULTS
In both trials, B16Arg/Arg subjects did not benefit compared with B16Gly/Gly subjects after salmeterol was initiated. In the first cohort, compared with placebo, the addition of salmeterol was associated with a 51.4 L/min lower A.M. peak expiratory flow (PEF; p = 0.005) in B16Arg/Arg subjects(salmeterol, n = 12; placebo, n = 5) as compared with B16Gly/Gly subjects (salmeterol, n = 13; placebo, n = 13). In the second cohort, B16Arg/Arg subjects treated with salmeterol and ICS concurrently (n = 8) had a lower A.M. PEF (36.8 L/min difference, p = 0.048) than B16Gly/Gly subjects (n = 22) treated with the same regimen. In addition, B16 Arg/Arg subjects in the second cohort had lower FEV1 (0.42 L, p = 0.003), increased symptom scores (0.2 units, p = 0.034), and increased albuterol rescue use (0.95 puffs/d, p = 0.004) compared with B16Gly/Gly subjects.


CONCLUSIONS
Relative to B16Gly/Gly patients with asthma, B16Arg/Arg patients with asthma may have an impaired therapeutic response to salmeterol in either the absence or presence of concurrent ICS use. Investigation of alternate treatment strategies may benefit this group.
Wechsler
Michael E
ME
Brigham and Women's Hospital, 75 Francis Street, Boston, MA, 02115, USA.
Lehman
Erik
E
Lazarus
Stephen C
SC
Lemanske
Robert F
RF
Boushey
Homer A
HA
Deykin
Aaron
A
Fahy
John V
JV
Sorkness
Christine A
CA
Chinchilli
Vernon M
VM
Craig
Timothy J
TJ
DiMango
Emily
E
Kraft
Monica
M
Leone
Frank
F
Martin
Richard J
RJ
Peters
Stephen P
SP
Szefler
Stanley J
SJ
Liu
Wenlei
W
Israel
Elliot
E
D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D000420:Albuterol / Q000031:analogs & derivatives* / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy* / Q000235:genetics*; D004359:Drug Therapy, Combination; D005260:Female; D005838:Genotype; D005938:Glucocorticoids / Q000008:administration & dosage; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011943:Receptors, Adrenergic, beta / Q000235:genetics*; D000068299:Salmeterol Xinafoate; D014221:Triamcinolone / Q000008:administration & dosage
D000318:Adrenergic beta-Agonists; D005938:Glucocorticoids; D011943:Receptors, Adrenergic, beta; D014221:Triamcinolone; D000068299:Salmeterol Xinafoate; D000420:Albuterol