I see two issues with your regex: First, as itimpi said, the vertical bar has special meaning, you'll need to escape it. Second, the asterisk as quantifier means "zero or more occurences", try using the plus quantifier, which means "one or more occurences". Thus, your regex should be
Also note that the regex engine used in Notepad++ is decidedly unsimilar to the Python one used in Calibre. For example, Notepad++ doesn't support matching regexes across multiple lines. Use the test facilities Calibre provides if you want to construct a regex for Calibre.