Pranlukast, a novel leukotriene receptor antagonist: results of the first European, placebo controlled, multicentre clinical study in asthma.
BACKGROUND
Leukotriene receptor antagonists have been shown to protect against bronchoconstriction induced by antigens, exercise, and cold air. There are relatively few clinical studies reported in patients with asthma. The present study is the first clinical evaluation of pranlukast (SB 205312, ONO-1078) outside Japan in patients with asthma.


METHODS
A randomised, double blind, placebo controlled, parallel group, multicentre four week study of the safety and tolerability of oral pranlukast, 225 or 337.5 mg twice daily, was performed in patients with mild to moderate asthma. Preliminary efficacy data were obtained; the main efficacy variables evaluated were forced expiratory volume in one second (FEV1) and morning domiciliary (home) peak expiratory flow rates (PEFR). Clinic PEFR and daytime and night-time asthma symptom scores were also recorded.


RESULTS
Compared with the placebo group the improvement in morning home PEFR was statistically significant at all time points for patients receiving pranlukast 337.5 mg twice daily and at weeks 1 and 2 for those treated with pranlukast in a dose of 225 mg twice daily. Mean morning home PEFR increased by 10.8 to 18.61/min (95% CI 0.2 to 29.3 l/min) in patients treated with pranlukast compared with a slight deterioration in those given placebo. FEV1 significantly increased within one hour after the first dose of pranlukast compared with baseline and this increase was maintained for eight hours. Improvements in trough FEV1-that is, at the end of the dosing interval-were statistically significant for the group treated with pranlukast 225 mg twice daily compared with placebo at week 4. Mean increases in FEV1 ranged from 210 ml to 340 ml (95% CI 60 to 500 ml) at trough in the pranlukast group. Patients treated with pranlukast also showed improvements in summary symptom and night-time asthma scores. Pranlukast was well tolerated, and no drug related changes in haematological and biochemical variables were observed.


CONCLUSIONS
Pranlukast, an oral leukotriene receptor antagonist, is well tolerated and is effective for the treatment of asthma. It increased FEV1 within one hour of dosing, improved patient summary symptom and night-time asthma scores, and reduced the use of rescue bronchodilators, thus providing further evidence of a role for leukotrienes in the pathogenesis of asthma.