Actually outputting a captured Regex value

I'm wondering if I'm missing something with this module.

I have an issue I'm trying to solve where I have "Job Title, Organization" and I want to output just "Job Title". I can get this filter to identify the right fields, but replacing the output is a whole other thing. Why can't I just output $1 or something like that from the filtered value here? None of the example seem to address the "Regex Pattern to Replace With" portion of the output, they're all blank. When I put in a regex in there, it just outputs the regex. I've tried adding {{ }} or {% %} wrappers, trying to output $1 on it's own and nothing.