Evaluating the potential of relapse-free survival as a surrogate for overall survival in the adjuvant therapy of melanoma with checkpoint inhibitors

Abstract Introduction Recent changes in the adjuvant treatment of melanoma have raised interest in confirming relapse-free survival (RFS) as a surrogate for overall survival (OS). Methods We explore this issue with the meta-analytic framework, using individual patient data from the European Organisation for Research and Treatment of Cancer (EORTC) 18071 trial of ipilimumab and published results from other adjuvant trials. Results The individual patient data analysis results at a median follow-up of 5.3 years showed a strong association between RFS and OS at the patient level (ρ = 0.84; 95% confidence interval [CI]: 0.82–0.87) and a moderate association at the trial level (R2 = 0.59; 95% CI: 0.08–1.00). Conclusions The trial-level association previously observed in interferon-based trials appeared to be maintained when the EORTC 18071 results were added to a regression analysis using published results from other trials. More data from adjuvant trials are required to confirm the strength of association between RFS and OS in this setting.