import re
query = "ABCDE"
full_text = "%EFGHI\r>XXXXX\r>XXXXX\r%IWANT\r>XXXXX\r>ABCDE"
print(re.search("%([^\r]*)(?=(?:\r(?!%)[^\r]*)*\r>[^\r]*{})".format(query), full_text).group(1))