Getting meta content from get_next_post & get_previous_post

Is it possible to retrieve meta content for the get_next_post() and get_previous_post()?

I'm currently using the following method, but not having much luck:

?php $prev_post = get_previous_post(); ?
?php $prev_post-post_title(); ? /* Returns content */
?php echo get_post_meta( $prev_post-ID, 'meta_box1', true); ? /* Doesn't return content */

Should I be forming the call differently?