Study objective: To determine the effects of a specific
thromboxane A2 (TxA2) receptor antagonist,
seratrodast, on asthma control and airway secretions.
Design: Multicenter, double-blind, randomized,
patients with mild to moderate asthma who had been continuously
expectorating sputum of > 20 g/d. Patients with a current pulmonary
infection or taking oral corticosteroids, antibiotics, or mucolytic
agents were excluded from the trial.
Following a 2-week run-in period, while pulmonary function, sputum
production, and mucociliary function were assessed, patients were
assigned to receive seratrodast, 40 mg/d, or placebo for 6 weeks.
Measurements and results: During the treatment period, the
changes in FEV1 and peak expiratory flow (PEF) were not
different between the two patient groups, but there were significant
reductions in diurnal variation of PEF (p = 0.034), frequency of
daytime asthma symptoms (p = 0.030), and daytime supplemental use ofβ
2-agonist (p = 0.032) in the seratrodast group. For
sputum analysis, seratrodast treatment decreased the amount of sputum
(p = 0.005), dynamic viscosity (p = 0.007), and albumin
concentration (p = 0.028), whereas it had no effect on elastic
modulus or fucose concentration. Nasal clearance time of a saccharin
particle was shortened in the seratrodast group at week 4 (p = 0.031)
and week 6 (p = 0.025), compared with the placebo group.
Conclusion: Blockade of TxA2 receptor has
minimal effects on pulmonary function, but may cause an improvement in
mucociliary clearance by decreasing the viscosity of airway