Efficacy and safety of interferon-alpha 1b combined with PD-1 monoclonal antibody in patients with unresectable stage IV melanoma: a retrospective study

Purpose The low objective response of immune checkpoint inhibitors (ICIs) remains a great challenge in advanced melanoma therapy. Interferon-alpha has been proven to be a promising combination regimen with ICI in a phase Ib/II trial. Herein, we evaluated the efficacy and safety of interferon-alpha 1b plus PD-1 monoantibody in a real-world Chinese metastatic melanoma cohort. Methods Profiles of patients diagnosed with unresectable stage IV (AJCC 8th Edition) between December 1st, 2018 and February 28th, 2022 from the Department of Dermatology, Xijing Hospital were reviewed. All of them received the combination treatment of interferon-alpha 1b (600 μg every other day) plus PD-1 monoantibody (Pembrolizumab 2 mg/kg or Toripalimab 240 mg or Sintilimab 200 mg, every 3 weeks) for at least 12 weeks. The efficacy was assessed by Response Evaluation Criteria in Solid Tumors (RECIST V1.1). The safety data were identified according to Common Terminology Criteria for Adverse Events (CTC AE) V.5.0. Results In total, 70 patients were included. 50% were females. 52.9% were with ECOG performance status ≥ 1. The fraction of patients receiving Pembrolizumab, Toripalimab, and Sintilimab was 28.6%, 67.1%, and 4.3%, respectively. Acral and mucosal subtypes accounted for 48.6% and 20%. The median follow-up period is 15.1 months. The objective response rate was 32.8%. The median time of overall survival was 18 months (95% CI 14.2–21.8 months), and the median time of PFS was 5.2 months (95% CI 4.2–6.2 months). The incidence of adverse events (any grade) was 98.6%, but only 8.6% of cases experienced grade 3 or 4 adverse reactions. Conclusion The combination of interferon-alpha 1b and PD-1 monoantibody demonstrated promising anti-tumor effects and acceptable toxicity in Chinese metastatic melanoma patients with cutaneous, acral, and mucosal subtypes.