For one of the artists on my iTunes music library, I've purchased music from iTunes Store. With iTunes 12, there's now a Biography panel and Similar Artists panel on the right that I can't get rid of - so far I've disabled "Show Apple Music" in the General preferences, and I've also disabled "Apple Music Connect" in the Parental preferences. Unfortunately it's still showing. Is there any way to not have that panel show?
I have yet to update my iTunes (and now I'm starting to think I should avoid it all together!) I was, however, able to search an Apple discussion board and found this to be the closest fix (hopefully) to what you are asking for:
Go to Edit>Preferences>Parental>Check the Apple Music Connect>Restart iTunes.
Apparently this user has a PC but they said they assume it will be easy to do on a Mac as well. Here's the link to the discussion board I referenced. Hope this helps!