Getting just domain expiry?

How can I get just the domain expiry from a WHOIS lookup?

I've tried this:

$domainreq = "example.com";
include 'src/whois.main.php';
include 'src/whois.utils.php';
$whois = new Whois('domain.expires');
$query = "$domainreq";
$result = $whois->Lookup($query);
$resout = str_replace('{query}', $query, $resout);
$utils = new utils;
$winfo = $utils->showHTML($result);