Efficacy and safety of nivolumab in Japanese patients with previously untreated advanced melanoma: A phase II study

Treating advanced or recurrent melanoma remains a challenge. Cancer cells can evade the immune system by blocking T‐cell activation through overexpression of the inhibitory receptor programmed death 1 (PD‐1) ligands. The PD‐1 inhibitor nivolumab blocks the inhibitory signal in T cells, thus overcoming the immune resistance of cancer cells. Nivolumab has shown promising anticancer activity in various cancers. We carried out a single‐arm, open‐label, multicenter, phase II study to investigate the efficacy and safety of nivolumab in previously untreated Japanese patients with advanced melanoma. Twenty‐four patients with stage III/IV or recurrent melanoma were enrolled and received i.v. nivolumab 3 mg/kg every 2 weeks until disease progression or unacceptable toxicity. The primary endpoint was overall response rate evaluated by an independent radiology review committee. The independent radiology review committee‐assessed overall response rate was 34.8% (90% confidence interval, 20.8–51.9), and the overall survival rate at 18 months was 56.5% (90% confidence interval, 38.0–71.4). Treatment‐related adverse events (AEs) of grade 3 or 4 only occurred in three patients (12.5%). Two patients discontinued nivolumab because of AEs, but all AEs were considered manageable by early diagnosis and appropriate treatment. Subgroup analyses showed that nivolumab was clinically beneficial and tolerable regardless of BRAF genotype, and that patients with treatment‐related select AEs and with vitiligo showed tendency for better survival. In conclusion, nivolumab showed favorable efficacy and safety profiles in Japanese patients with advanced or recurrent melanoma, with or without BRAF mutations. (Trial registration no. JapicCTI‐142533.)