<qa>  What is the primary efficacy endpoint?To evaluate the efficacy of ASA as add-on therapy in COPD in comparison to placebo a prospective, randomized, double-blind, placebo controlled study will be conducted. Adult male and female patients n74 with proven COPD GOLD grade II-III will be randomized to 2 groups i.e. 37 patients per group, stratification according to smoking status and gender. They will receive either 500 mg ASA per day or matching placebo over 12 weeks. Primary efficacy endpoints are changes in the lung-functional parameter FEV1 forced expiratory 1-second volume after 12 weeks of treatment. Secondary endpoints are the health score of the St. Georges respiratory questionnaire SGRQ and Peak-flow PEF. 