$re = '/^[A-zÀ-ÿ ]*\1*,(?:\s)(\w*,\s)(CEP (\d{5}-\d{3}))/im';
$str = 'Rua das Flores, 123, CEP 60321-105
Avenida Brasil, 456A, CEP 16945-017
Travessa dos Santos, 101, CEP 12345-678
Rua Catarina, 243, CEP 25437-987
Rua Sâo Pedro, 243, cep 25437-987
';
$subst = "\^[A-Za-z ]*\1*,(?:\s)(\w*,\s)(CEP (\d{5}-\d{3}))\\";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php