Apologies- One more REGEX help

Hello,

I had a key change in my r code and now my regex is not working.  I'm trying to parse out the below bold/italic text.  The bold/italic will always change (in case of the knots, it could be more or less numbers) but the rest will stay the same. 

I've tried "\w*\((\w*)\,.*\((.*)\)\).*(/w)" but that does not seem to work.

bs(rba_bucket, knots = c(3250, 40000), degree = 1)2

Thank you for the help.