sanitize data on "IN" clauses with wpdb

gistfile1.php

<?php

$menu_items = array();
foreach ( $menus[$menu] as $item ) $menu_items[] = $item['id'];
$placeholders = implode(', ', array_fill(0, count($menu_items), '%s'));
$query = "SELECT post_name, ID, post_title FROM $wpdb->posts WHERE post_name IN($placeholders)";
$results = $wpdb->get_results( $wpdb->prepare($query, $menu_items), OBJECT_K );