I had similar kind of Requirement which was we have to display text only occurs in between colon and hypen (":" and "-") so I used below line which worked successfully
LTRIM(RTRIM(TRIM (BOTH ':' FROM REGEXP_SUBSTR({fieldname}, ':[^-]+'))))
Example line
**Computer, Internet & Software: Atlassian - Business Software**
then the ouctcome was
**Atlassian**
this Formula i have used inside a saved search result in NetSuite Environment
