Mysql PDO statement with params in HAVING problem

Hi everyone, im new here, so please correct me if i created or formated
topic incorrectly.

I found a problem. I have a simple query for my needs:

    $stmt = $dbh->prepare("SELECT concat(first_name,' ',last_name) as
    full_name,t.* FROM `specialists` `t` HAVING full_name like '%john%'");
    $stmt->execute();
    while($row = $stmt->fetch())
    {
       echo '<pre>'; var_dump($row); echo '</pre>';
    }

It works fine, until i add a param to my query:

    $stmt = $dbh->prepare("SELECT concat(first_name,' ',last_name) as
    full_name,t.* FROM `specialists` `t` HAVING full_name like '%:query%'");
    $stmt->execute();
    $query = 'londo';
    $stmt->bindParam(':query',$query);
    while($row = $stmt->fetch())
    {
       echo '<pre>'; var_dump($row); echo '</pre>';
    }

Now there is nothing in fetch(). Is it a bug ?

Thanks.