Adjuvant <scp>PD</scp> ‐1 inhibitor versus high‐dose interferon α‐2b for Chinese patients with cutaneous and acral melanoma: A retrospective cohort analysis

e21516 Background: The clinical efficacy of PD-1 inhibitors as an adjuvant treatment for Asian melanoma patients has not yet been determined. Methods: Thus, this single-centre, retrospective study analysed the clinical data of 90 Chinese patients with completely resected, stage III cutaneous or acral melanoma who received either adjuvant PD-1 inhibitor or high-dose interferon α-2b (HDI). Propensity score matching (PSM) was used to control baseline differences between the two treatment groups. The primary end point was recurrence-free survival (RFS), and the secondary end points included distance metastasis-free survival (DMFS) and incidence of first distant metastatic sites. Results: Anti-PD-1 treatment resulted in significantly longer RFS (18-month RFS, 53.3% versus 26.7%; 95% CI, 0.097-0.975; P < 0.05) and DMFS (18-month DMFS, 70.9% versus 46.1%; 95% CI, 0.13-0.945; P < 0.05) than HDI in cutaneous melanoma patients. However, adjuvant anti-PD-1 treatment had no advantage over HDI in acral melanoma patients (18-month RFS, 30.0% versus 35.9%; P > 0.05; 18-month DMFS, 36.5% versus 63.6%; P > 0.05). The incidence of lung metastasis at first in the anti-PD-1 group was found to be significantly lower (12.5% versus 48.5%; P < 0.05) in cutaneous melanoma patients than in acral melanoma patients, but no difference in metastatic sites were observed between the two treatment groups among acral melanoma patients. The incidence of treatment-related AEs was similar between the two treatment groups. Conclusions: In conclusion, adjuvant anti-PD-1 treatment was well tolerated and yielded a significantly better prognosis than HDI in Chinese patients with stage IIIB/C cutaneous melanoma, but a significant difference was not observed in those with acral melanoma.