28639
Although safety and efficacy continue to be the two main metrics by which drugs will be judged , the newer agents in the market also face challenges of a more comparative nature - are they more efficacious than the currently available drugs on the market ?
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 None