my $remove = quotemeta "{ (This Word) }";
print $remove; # See what happened.
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You can also shorten it to

my $text   = 'to { (This Word) }';
my $remove = '{ (This Word) }';

$text =~ s/\R//g;
$text =~ s/\Q$remove//; # <-- the \Q means quotemeta
[download]