Comparing the clinical efficacies of anti-PD-1 antibody monotherapy and anti-PD-1 and anti-CTLA-4 combination therapy as first-line immunotherapy in Japanese advanced acral melanoma: A retrospective, multicenter study (JAMP-neo study).
Authors: Yasuhiro Nakamura, Yukiko Kiniwa, Hiroshi Kato, Osamu Yamasaki, Takeo Maekawa, Shigeto Matsushita, Tatsuya Takenouchi, Takashi Inozume, Yasuo Nakai, Satoshi Fukushima, Shintaro Saito, Atsushi Otsuka, Noriki Fujimoto, Taiki Isei, Natsuki Baba, Taisuke Matsuya, Ryo Tanaka, Takahide Kaneko, Masazumi Onishi, Shusuke Yoshikawa
Journal: Journal of Clinical Oncology (2021)

9542 Background: Anti-PD-1 antibody monotherapy (PD1) has been commonly used for patients with advanced acral melanoma (AM). However, recent studies have demonstrated the limited clinical efficacy of PD1 in AM compared to non-acral cutaneous melanoma, particularly in nail apparatus melanoma. Although advanced AM patients are strong candidates for first-line anti-PD-1 and anti-CTLA-4 combination therapy (PD1+CTLA4), data on the clinical efficacy of PD1+CTLA4 in AM are lacking. Thus, we aimed to compare the clinical efficacies of PD1+CTLA4 and PD1 in Japanese advanced AM patients. Methods: We retrospectively reviewed the clinical records of advanced AM patients treated with PD1+CTLA4 or PD1 as first-line immunotherapy at 23 Japanese institutions. Clinical response was assessed using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Survival was estimated using Kaplan-Meier analysis. Toxicity was assessed according to CTCAE 4.0. Results: A total of 192 patients (median age, 72 years) with advanced AM (palm and sole melanoma, 135; nail apparatus melanoma, 57) were included in the study. PD1+CTLA4 and PD1 were used as first-line immunotherapy in 39 and 153 patients, respectively. The baseline demographics and characteristics were similar between the PD1+CTLA4 and PD1 groups, except for age (median age 67.3 vs. 73.2; P = 0.005). The objective response rate (ORR) in PD1+CTLA4 was significantly higher than that of the PD1 group (38.5% vs. 16.3%; P = 0.047). The median progression-free survival (PFS) and overall survival (OS) in the PD1+CTLA4 group tended to be longer than those of the PD1 group, but the differences were not significant (median PFS 7.3 months vs. 4.5 months; P = 0.19, median OS 43.6 months vs. 18.2 months; P = 0.19). In the subgroup analysis of the palm and sole melanoma cohorts, no significant differences in ORR, PFS, and OS were observed between the PD1+CTLA4 and PD1 groups (ORR 31% vs. 20.8%; P = 0.67, median PFS 5.3 months vs. 5.9 months; P = 0.87, median OS not reached vs. 22.3 months; P = 0.66). Meanwhile, the nail apparatus melanoma cohort in the PD1+CTLA4 group exhibited significantly higher ORR, and longer PFS and OS than the PD1 group (ORR 60% vs 6.1%; P &lt; 0.001; median PFS 19.6 months vs 3.8 months; P = 0.008, median OS 43.6 months vs 13.5 months; P = 0.049). Due to immune-related adverse events in all cohorts, the treatment cessation rate was higher in the PD1+CTLA4 group than the PD1 group (59% vs. 11.8%). Conclusions: PD1+CTLA4 was clinically more efficacious than PD 1 in advanced AM patients. Notably, advanced nail apparatus melanoma patients were strong candidates for first-line PD1+CTLA4.