The Degree of Programmed Death-Ligand 1 (PD-L1) Positivity as a Determinant of Outcomes in Metastatic Triple-Negative Breast Cancer Treated With First-Line Immune Checkpoint Inhibitors

Abstract

In metastatic triple-negative breast cancer (TNBC), the efficacy of immune checkpoint inhibitors (ICIs) in combination with chemotherapy has been demonstrated in randomized clinical trials (RCTs). Despite this, an indirect comparison is not yet available. Reconstruction of individual patient data from Kaplan-Meier curves allows the indirect comparison of different treatments. We analyzed six overall survival (OS) curves from three RCTs. In patients with ≥1% positivity, atezolizumab was found to determine a significantly better OS than pembrolizumab. As regards pembrolizumab, adopting a threshold of PD-L1 positivity ≥10% (as opposed to ≥1%) improved median survival to a remarkable extent (23.0 vs 15.5 months).