$re = '/z:Assembly=\\\\"0\\\\">(?<fieldValue>(?:(?!<\/value>).)*)<\/value>/';
$str = '<value z:Id=\\"8\\" z:Type=\\"System.String\\" z:Assembly=\\"0\\">Status.</value>';
$subst = "";
$result = preg_replace($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