15917
Post - hoc analysis of two phase III clinical studies found that the phosphodiesterase 4 ( PDE4 ) inhibitor , roflumilast , reduced exacerbation frequency in patients with severe chronic obstructive pulmonary disease ( COPD ) who were taking inhaled corticosteroids ( ICS ) concomitantly , whereas patients not taking ICS derived no such benefit .
 Chemical: roflumilast
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: roflumilast