ABSTRACT
Background and objective: Suplatast tosilate is a Th2 cytokine inhibitor that is effective for controlling persistent asthma. However, the long-term efficacy of suplatast is unknown. We compared the clinical efficacy of long-term monotherapy with suplatast tosilate with a low dose of inhaled steroids in patients with mild atopic asthma. Methods: A total of 32 patients with mild atopic asthma were randomly assigned to receive suplatast (n = 15) or fluticasone (n = 17). In the suplatast group, 100 mg of suplatast was given orally 3 times a day (total daily dose = 300 mg) for 2 years. In the fluticasone group, 100 mg of fluticasone was inhaled twice a day (total daily dose = 200 µg) for 2 years. Results: In the suplatast group, the improvements in peak expiratory flow (PEF) rate and forced expiratory volume in 1 second (FEV1) and the changes in the symptom diary scale and frequency of β2 stimulant inhalation were generally similar to those in the fluticasone group, and efficacy was maintained for 2 years. Improvements in inflammatory indices, such as the sputum eosinophil cationic protein (ECP) level and exhaled nitric oxide concentration, were comparable in the suplatast and fluticasone groups. The improvement in airway hyper-responsiveness was also similar in the 2 groups. The peripheral blood eosinophil percent change, serum ECP level, and total IgE antibody titer improved only in the suplatast group. Conclusions: Long-term treatment with suplatast significantly improved symptoms and inflammatory indices in patients with mild atopic asthma. Along with fluticasone, suplatast is considered a useful drug for the management of mild atopic asthma.