$re = '/(\s?)[^;]+?\s?<([^>]+)>(?:;*$)?/m';
$str = 'Joe Smith <Joe.smith@url.com>; Mary Jones <Mary.Jones@url.com>; Marjorie S. Johnson <mjohnson1@url.com>; James Carl-Smith <James.carl-smith@url.com>;';
$subst = "$1$2";
$result = preg_replace($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