Meta-analysis of addition of immune checkpoint inhibitors to first-line chemotherapy for triple-negative breast cancer

Patients with triple-negative breast cancer (TNBC) have limited therapeutic options. Systematic review and meta-analysis of seven randomized controlled trials (4631 patients), published after 2017, evaluated addition of immune checkpoint inhibitors to first-line chemotherapy for TNBC. Addition of ICIs to first-line chemotherapy was associated with improved progression-free survival among all patients (panel A) and PD-L1 positive patients (panel B) but not among PD-L1 negative patients. Addition of ICIs to first-line chemotherapy was associated with improved overall survival among PD-L1 positive patients only. The ORR was improved with addition of ICIs to first-line chemotherapy in all three groups. Addition of ICIs to chemotherapy was associated with higher risk of grade 3-5 adverse events (OR 1.43; p<0.001). The authors conclude that addition of ICIs to first-line chemotherapy for TNBC was associated with increased efficacy, most notable among PD-L1 positive patients, but also with increased risk of adverse events.