Salmeterol decreases eosinophilic cationic protein and rescue medication in patients inhaling beclomethasone dipropionate: preliminary study in mild and moderate asthma in Trinidad, West Indies.

Abstract

Activated eosinophils play a critical role in asthma pathogenesis, and eosinophil cationic protein (ECP) is a useful indicator of inflammation. Inhaled corticosteroids and long-acting beta2-agonists (LABA) effectively control asthma symptoms and improve airway function. Salmeterol's anti-inflammatory efficacy as add-on therapy to inhaled corticosteroids has not been evaluated in Caribbean populations. We investigated nine non-smoking subjects (three men and six women; mean age: +/- SE, 50.7 +/- 3.82 years) with stable mild and moderate persistent asthma who were inhaling > or = 500 microg beclomethasone dipropionate (BDP) daily. This was a with-in-patient controlled laboratory blind study performed over 8 weeks. Patients received BDP for 2 weeks, add-on salmeterol 100 microg in weeks 3-6 and BDP alone in weeks 7-8. Patients recorded daily morning and night symptoms. Morning peak expiratory flow rate was measured on entry to the study and with sputum ECP at the end of weeks 2, 4, 6 and 8. Salmeterol together with BDP decreased sputum ECP from a pretreatment median value of 897.84 microg/l to 628.38 microg/l after 4 weeks, and ECP continued to decrease even after salmeterol withdrawal. Both drugs decreased the frequency of rescue medication use by approximately 50% and increased the median number of days per week without rescue salbutamol from 0 to 3 days. Salmeterol's bronchoprotective effect was maximal after 4 weeks and was sustained after its withdrawal. In conclusion, this study, performed in Trinidadian asthmatics, used ECP as a surrogate marker of bronchial inflammation and supports the recent Salmeterol Multi-center Asthma Research Trial (SMART) data recommending add-on salmeterol therapy to adequate anti-inflammatory medication such as inhaled corticosteroids for optimal asthma management. Further studies are required to evaluate the anti-inflammatory efficacy and possible tolerance to salmeterol in Caribbean patients.