KP_what_I_want (space)
or
KP_what_I_want(
or
KP_what_I_want (
or
KP_what_I_want +
etc...

##</code><code>##

my ($exp) = 
    $line =~ m/ 
                    KP_          # Required 
                    (.*)            # Capture Desired Output
                    (?:\s)?      # Optional - Do not capture
		    (?:\()?         # Optional - Do not capture
     /xi;