Reduction of the severity of bronchial hyperresponsiveness by the novel leukotriene antagonist 4-oxo-8-[4-(4-phenyl-butoxy)benzoylamino]-2- (tetrazol-5-yl)-4H-1-benzopyran hemihydrate.

There is much evidence that the cysteinyl-leukotrienes (C-LTs) are important in the pathogenesis of asthma. The clinical effect of a new leukotriene antagonist, ONO 1078 (4-oxo-8-[4-phenylbutoxy)benzoylamino]-2-(tetrazol-5-yl)-4H- 1-benzopyran hemihydrate, CAS 103177-37-3) on symptoms, pulmonary lung function and bronchial hyperresponsiveness was evaluated in patients with bronchial asthma. Eleven patients were treated for 24 weeks with 450 mg of ONO 1078 twice daily. The score of asthma symptom severity and the number of inhaled procaterol were significantly reduced after 2 weeks of ONO 1078 treatment and remained decreased for another 22 weeks. Their FEV1 and PC20 to histamine significantly improved 12 and 24 weeks after ONO 1078 treatment. The effectiveness of ONO 1078 suggests that the C-LTs play an important role in the pathogenesis of asthma. ONO 1078 might help to favorably modify the pathophysiologic condition in patients with bronchial asthma.