3770
The mean increase in CD4 cells at week 4 was 73 . 8 cells / mm3 and 52 . 4 cells / mm3 for the combination and zidovudine groups , respectively ( p > 0 . 36 ) .
 Chemical: zidovudine
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: zidovudine