Effect of Suplatast Tosilate on Antileukotriene Non-Responders with Mild-to-Moderate Persistent Asthma

BACKGROUND: Immunomodulatory therapy has been recently introduced for the management of asthma. Suplatast tosilate (ST), a new immune-modifying drug, is known to improve the airway function by inhibiting the release of Th-2 cytokines. However, its efficacy as a controller listed in the guideline, Global Initiative for Asthma 2005 has not been established. In this study we investigated the role of ST in leukotriene receptor antagonist (LTRA) non-responders with mild-to-moderate persistent asthma before initiating corticosteroids inhalation therapy. METHODS: This was a prospective open-level clinical trial. LTRAs was given to 41 patients with asthma for 4 weeks and clinical efficacy was assessed using daily symptom scores. The 10 patients, aged 2.5-8.5 years, who failed to show clinical improvement, were defined as LTRA non-responders. After a 1-week washout period, the efficacy of ST was investigated and compared with LTRA non-responders for the following 4 weeks. RESULTS: LTRA non-responders showed a significant improvement in the average symptom score, peak expiratory flow, use of rescue medication and the proportion of symptom-free days with ST therapy. CONCLUSIONS: ST is a good choice for patients who have failed to respond to LTRAs. ST should therefore be added to the list of treatment options for such patients.