Kiyohara Y, et al. - Herein, an interim analysis was conducted to assess the safety and effectiveness of nivolumab in Japanese patients with malignant melanoma. At the last evaluation, the improvement rate based on the antitumor response was seen to be 22.2%. Infrequent serious adverse drug reactions (ADR) of special interest were noted. No new safety concerns were raised. An equivalent effectiveness of nivolumab was noted in the patients with mucosal melanoma and those with cutaneous melanoma.