$re = '/((MR|VR) ){1}((LAS|VIE|FAD) \d{1,3}.\d{1,3}.\d{1,3}( )){1}(\d{1,3}(P)){1}( DUMMY)?/m';
$str = 'MR LAS 1.01.01 4P
Prefix MR LAS 1.01.01 4P Postfix
Prefix MR LAS 1.01.01 4P Kürbis Postfix
MR LAS 1.01.01 fail 4P Postfix
MR LAS 1.01.01 fail 4P Kürbis Postfix
MR LAS 1.1.1 4P
MR LAS A.0.1 4P
';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
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