Query Manager - REGEXP_REPLACE

I'm trying to remove HTML tags in a query. We need to use Query Manager, so our ePerformance admins can monitor. I've tried this expression, but doesn't seem to work. EP_RESULTS is the long description field. Expression type is Long Description, with the Aggregate checkbox selected. What am I doing wrong? Do I need to use this as a field too?

REGEXP_REPLACE(I.EP_RESULTS, '<[^>]*>|&npsb;|& npsb;', ' ')