Comparative-effectiveness of pembrolizumab vs. nivolumab for patients with metastatic melanoma

Background: Pembrolizumab (P) and nivolumab (N) are commonly used therapies for advanced melanoma. However, their effectiveness has never been directly compared, leaving little guidance for clinicians to select the best therapy. Therefore, we sought to retrospectively compare the overall survival of patients with metastatic melanoma treated with front line P or N in the real-world setting.Material and methods: This study included patients with advanced melanoma, diagnosed between 1 January 2011 and 31 July 2018, treated with frontline P or N who were included in a nationwide, longitudinal de-identified electronic health record (EHR)-derived database. Overall survival (OS) was estimated for each treatment group using Kaplan-Meier curves with a log-rank test. Comparison of OS was estimated using an inverse probability weighting model to reduce bias between the groups. The model was adjusted using age, sex, ECOG, LDH (elevated or not), BRAF (mutated or not), Kit (mutated or not), NRAS (mutated or not), PD-L1 expression (0% or greater), Body Mass Index, and primary site.Results: 888 patients with advanced disease who received treatment with frontline P (n = 486) or N (n = 402) were identified. Median OS for all patients treated with P was 22.6 months (m) and was 23.9 m for those treated with N (p = 0.91). In the inverse probability weight analysis there was no difference in survival between patients treated with P or N 1.06 (95% CI 0.84-1.33).Concluding Statement: In our retrospective, real-world analysis of patients with advanced melanoma, no statistical difference in OS was noted between patients treated with frontline P compared to N. This supports the current practice of choosing either P or N based on patient and provider preference.