1809
All the complaints disappeared after stopping pegylated interferon alpha - 2b and reappeared after restarting it .
 Chemical: pegylated interferon alpha - 2b
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: pegylated interferon alpha - 2b