A Double-Blind, Placebo-Controlled Trial of the Thromboxane Synthetase Blocker OKY-046 on Bronchial Hypersensitivity in Bronchial Asthma Patients

Abstract

We investigated the effect of thromboxane (TX) synthetase inhibitor, OKY-046, on bronchial hypersensitivity in 16 asthmatics by a double-blind, placebo-controlled, crossover trial. Bronchial sensitivity to methacholine was measured by Astograph. Blood samples were taken to measure plasma levels of TX metabolites. No significant differences of forced expiratory volume in 1 sec (FEV₁), bronchial sensitivity, or bronchial reactivity were observed after OKY-046 administration, compared to baseline or after placebo. However, responders showed a significant decrease in the plasma TXB₂/6-keto-PGF_1α ratio as compared to nonresponders. Our data failed to confirm an inhibitory effect of OKY-046 on bronchial hypersensitivity, but suggested the importance of its therapeutic dose monitoring.

Key Words:

• Asthma
• Thromboxane
• Bronchial hyperresponsiveness
• OKY-046
• Synthetase blocker