couple of naive questions about search patterns

[Dmitry Monakhov]

I want to tag new patches, but not replay messages.
I've tried to do it like this:
notmuch tag +patch-new "tag:inbox and subject:'patch' \
                        and not subject:'re:'"
but last rule (subject:'re:') seems to be ignored, as soon as i
understand this happens because pattern 're:' is too short.
Am i right? Are any other ways to accomplish this task?
BTW: Is it possible to specify beginning(^) or the end in subject
search pattern?