Monitoring real-life utilization of pembrolizumab in advanced melanoma using the Portuguese National Cancer Registry

To evaluate the effectiveness and safety of pembrolizumab use in advanced melanoma in a real-life context; and to explore the existence of an efficacy-effectiveness gap, comparing registry data with the reference clinical trial.

This study followed the guidelines for good pharmacoepidemology practice. An ambispective cohort was constituted, initiating the observation upon drug approval (17/07/2015) and following exposed patients until death or cut-off date (15/11/2019). The primary outcome was overall survival (OS); secondary outcomes comprised progression-free survival (PFS), overall response rate (ORR) and the occurrence of adverse events (AE). For all survival analyses, the Kaplan-Meier estimator was used, considering a 95% confidence interval (CI), aside with one-year survival rates.

A total of 125 patients constituted the cohort, originating from 16 hospitals in Portugal. Median OS was estimated to be 16.9 months (CI_95% 11.3-25.5) and the probability of survival after 1 year was 57.5% (CI_95% 48.4%-65.6%). Median PFS was estimated to be 4.8 months (CI_95% 3.9-6.7) and the probability of remaining progression-free after 1 year was 32.8% (CI_95% 24.8-41.1). ORR was 30.4% (CI_95% 22.5%-39.3%). AEs were experienced by 82% of patients, and 27% experienced AE≥ grade 3.

Our data suggest lower effectiveness in a real-life context than the efficacy reported in the clinical trial. Safety data seems, however, quite comparable to KEYNOTE-006.