Oncological outcomes of addition of anti-PD1/PD-L1 to chemotherapy in the therapy of patients with advanced gastric or gastro-oesophageal junction cancer: A meta-analysis

BACKGROUND: Patients with advanced gastric or gastro-oesophageal junction cancer (GC/GEJC) that fail to respond to prior chemotherapy have poor clinical prognosis. Lately, many trials have paid much attention on the oncological outcomes of immune checkpoint inhibitors (ICI). A new therapy based on programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors has recognized as promising prospects for advanced GC/GEJC. We assessed efficacy and safety of PD-L1 antibody versus chemotherapy alone in previously treated non-small cell lung cancer. METHODS: Computerized literature search was done on the published trials in: Pubmed, Embase, Cochrane library updated on June 2019. Randomized controlled trials were selected investigating chemotherapy plus PD-1/PD-L1 versus chemotherapy alone. RESULTS: Three randomized controlled trails were included. The pooled analysis of overall survival (OS) was longer with anti-PD1/PD-L1 than with chemotherapy alone in the OS (OR = 0.66, 95%CI = 0.47–0.92, P = .02) and sub-group OS of GEJC (OR = 0.73, 95%CI = 0.58–0.93, P = .01). Whereas, there is no significant difference in progression-free survival (OR = 0.93, 95%CI = 0.62–1.39, P = .72). The pooling adverse events (AE) data did not achieve advantage in the PD-1/PD-L1 targeted agents (OR = 0.53, 95%CI = 0.13–2.10, P = .36), the same as the treatment-related AE of grade 3 to 5 (OR = 0.53, 95%CI = 0.16–1.74, P = .30). CONCLUSIONS: Treatment of patients with advanced GC/GEJC with PD-1/PD-L1 targeted did result in an improvement in some but not all survival endpoints. Moreover, it had a comparable toxicity profile as compared with chemotherapy alone. More well designed studies are needed to develop a database of all anti-PD1/PD-L1 sub-groups and their individual impact on the differing anti-PD1/PD-L1 treatments.