CHARACTERIZATION OF THE WITHIN-SUBJECT RESPONSES TO FLUTICASONE AND MONTELUKAST IN CHILDHOOD ASTHMA
by Stan Szeffler, et al, in the Journal of Allergy and Clinical Immunology 2005:115:233-42.

The Child Asthma Research & Education Network of the National Heart Lung and Blood Institute that gave us the classic study known as the CAMP study (Oct. 2000 NEJM) has just published another KEY article which any physician who treats childhood asthma MUST read and have in his/her files.

The study was in 140 children, 6-17 years old with mild to moderate persistent asthma. They were randomized in a double masked cross over design using either 8 weeks of montelukast (dosed by the package insert) followed by 8 weeks of fluticasone propionate (100ug BID) or the same medication in reverse sequence over an 18 week period. The major outcome measured was an improvement in FEV1 of >7.5 %. The results were assessed in relation to asthma phenotype-associated biomarkers.

RESULTS: Based on an increase in FEV1 of > 7.5 %, 17 % responded to both mediations, 23 % responded to fluticasone alone, 5 % responded to montelukast alone, and 55 % showed no significant response to either drug!

A better differential response to fluticasone vs. montelukast was seen in those patients with a higher bronchodilator response & more frequent bronchodilator use, higher exhaled nitric oxide & eosinophil cationic protein levels, greater methacholine sensitivity and lower pulmonary function test values. A favorable response to montelukast was associated with children with younger age, shorter duration of disease & increased levels of urine leukotrienes. So generally, the more severe the asthma, the more likely the patient was to respond to the inhaled corticosteroid and the milder patients were associated with a better response to montelukast.

The authors suggest that asthma therapy might soon be based on the patient’s phenotypic and possibly genotypic characteristics.