$line =~ s/^myword \S+//; # strip myword, a space, and any stretch of non-spaces

##</code><code>##

$line =~ s/^              #strip, from the beginning of the string,
           myword\s+      #myword, followed by whitespace
           \S+            #followed by non-whitespace
           (?:,\s*\S+)*   #followed by any number of comma, optional whitespace, non-whitespace
          //x;          # update: two slashes are needed here