Genetic predictor of efficacy of anti-asthmatic agents for improving pulmonary function

A method for establishing a negative correlation between a pulmonary response to therapy with an inhaled corticosteroid and a pulmonary response to therapy with a leukotriene receptor antagonist in an individual characterized as being homozygous for arginine at residue 16 of a β2 adrenergic receptor, the method comprising the steps of:

• measuring a baseline pulmonary response for each of a plurality of subjects, each subject having the β2 adrenergic receptor;
• treating each subject with a pair of treatment agents, each agent being administered separately for a clinically relevant period in a randomized crossover treatment sequence, the agents being the inhaled corticosteroid and the leukotriene receptor antagonist;
• determining a change in response from the baseline pulmonary response for each subject after each treating step, where a positive pulmonary response is an increase from the baseline and a negative pulmonary response is a response that is not a positive pulmonary response;
• assigning each subject to one of a plurality of groups defined by genotype that encodes amino acid 16 of the B2AR gene, at least one group containing subjects homozygous for arginine;
• plotting a regression plot between responses to the treatment agents for each group;
• identifying in the regression plot a negative correlation between the pulmonary response to the treatment agents in the arginine-homozygous subjects, wherein said homozygous subjects exhibit a positive pulmonary response to the therapy with the inhaled corticosteroid and a negative pulmonary response to the therapy with the leukotriene receptor antagonist.