$re = qr{
  \( (?{ local $N = 1 })
  (?:
    (?(?{ !$N })(?!))
    (?:
      \( (?{ local $N = $N + 1 })
      |
      \) (?{ local $N = $N - 1 })
      |
      [^()]+
    )
  )+
  (?(?{ $N })(?!))  # fixed, thanks to Hofmator
}x;

$text =~ s/$re//g;