import re
s = "abc keyword1 ddd 111 ddd (ddd 99/ddd) 1 ddd (ddd) ddd 11 ddd keyword2 abc"
m = re.search(r'keyword1(.*?)keyword2', s, re.I | re.S)
if m:
print( re.sub(r'(\([^()]*\))|\s*\d+', r'\1', m.group(1)) )
aW1wb3J0IHJlCnMgPSAiYWJjIGtleXdvcmQxIGRkZCAxMTEgZGRkIChkZGQgOTkvZGRkKSAxIGRkZCAoZGRkKSBkZGQgMTEgZGRkIGtleXdvcmQyIGFiYyIKbSA9IHJlLnNlYXJjaChyJ2tleXdvcmQxKC4qPylrZXl3b3JkMicsIHMsIHJlLkkgfCByZS5TKQppZiBtOgogICAgcHJpbnQoIHJlLnN1YihyJyhcKFteKCldKlwpKXxccypcZCsnLCByJ1wxJywgbS5ncm91cCgxKSkgKQo=