Pharmacogenetic characterization of indacaterol, a novel beta 2-adrenoceptor agonist.
OBJECTIVE
Indacaterol is a novel beta(2)-adrenoceptor agonist in development for the treatment of chronic obstructive pulmonary disease. The aim of this study was to investigate the comparative pharmacology of indacaterol in recombinant cells expressing the common polymorphic variants of the human beta(2)-adrenoceptor and in human primary airway smooth muscle (ASM) cells.


METHODS
Chinese hamster ovarian-K1 cell lines expressing high and low levels of the common human beta(2)-adrenoceptor variants were generated [Gly16-Glu27-Val34-Thr164(GEVT), RQVT, GQVT] and also the rare GQVI variant. Human primary ASM cells were isolated from explants of trachealis muscle. Adenosine-3',5'-cyclic-monophosphate production was used as an outcome measure.


RESULTS
In both the low- and high-expression recombinant GEVT 'wild type' cell lines indacaterol is a high-efficacy agonist. Salmeterol and formoterol were identified as low- and high-efficacy agonists, respectively, and showed similar potencies to indacaterol irrespective of the beta(2)-adrenoceptor genotype. The I164 variant cell line was associated with a reduced capacity to generate adenosine-3',5'-cyclic-monophosphate in response to beta(2)-adrenoceptor agonist. In the human primary ASM cells indacaterol gave a maximal response intermediate between that of salmeterol and formoterol.


CONCLUSIONS
These data demonstrate that indacaterol is a high-efficacy agonist in recombinant cell systems but acts with lower efficacy in human primary ASM cells. No marked genotype-dependent effects were observed for common variants; however, changes in I164 receptor activity were identified, which were dependent on the level of expression of beta(2)-adrenoceptors.
Division of Therapeutics & Molecular Medicine, University Hospital of Nottingham, Nottingham, UK. ian.sayers@nottingham.ac.uk
I
I
Sayers
J
J
Hawley
C E
CE
Stewart
C K
CK
Billington
A
A
Henry
J R
JR
Leighton-Davies
S J
SJ
Charlton
I P
IP
Hall
D058666:Adrenergic beta-2 Receptor Agonists; D000818:Animals; D016466:CHO Cells; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000096:biosynthesis; D014644:Genetic Variation / Q000187:drug effects; D006801:Humans; D007189:Indans / Q000494:pharmacology*; D010597:Pharmacogenetics / Q000379:methods; D020641:Polymorphism, Single Nucleotide / Q000187:drug effects / Q000235:genetics; D015363:Quinolones / Q000494:pharmacology*; D018343:Receptors, Adrenergic, beta-2 / Q000235:genetics*
D058666:Adrenergic beta-2 Receptor Agonists; D007189:Indans; D015363:Quinolones; D018343:Receptors, Adrenergic, beta-2; C510790:indacaterol; D000242:Cyclic AMP