18211
Although a number of biosimilar proteins have been approved , especially in Europe , issues on substitutability , extrapolation to other disease indications , and selection of reference standards and comparators , remains to be standardized at a global level .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None