$re = '/^(.*?\[br]).+?(?=\[\*.*?](?<!].)(?!])|$)/m';
$str = '[[拱|{{{#!html}}}]][br]팔짱낄 공\'\'\':\'\'\'
[[顆|{{{#!html}}}]][br]낟알 과\'\'\'-\'\'\'[* some annotation that may include quote marks(\', ") and brackets("(", ")", "[[", "]]").]
[[廓|{{{#!html}}}]][br]둘레 곽[br]클 확[* another annotation.][* another annotation.]
';
$subst = "$1AAAA";
$result = preg_replace($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