Pandora Hearts, Heart no Kuni no Alice: Wonderful Wonder World Recommendations
I might be wrong but I think the similarity is that both Pandora Hearts and Heart no kuni no Alice ~Wonderful Wonder World~ kind of related to Alice in Wonderland. Alice in Pandora Hearts is both the rabbit (B-rabbit) and Alice. Heart no Kuni no Alice ~Wonderful Wonder World~ has bishie rabbit guy and Alice from foreign country.
Both are inspired by Alice in Wonderland and have mysterious plot-lines with a gruesome/violent twist.