Anti-PD-1/PD-L1 antibody versus conventional chemotherapy for previously-treated, advanced non-small-cell lung cancer: a meta-analysis of randomized controlled trials.

Background: The anti-PD-1/PD-L1 monoclonal antibody has showed promising results in various cancers via enhancing T cell functions. However, many questions remain in the role and safety in previously-treated, advanced non-small-cell lung cancer (NSCLC). Thus, we conducted a meta-analysis incorporating all available evidences to evaluate the efficacy and safety of anti-PD-1/PD-L1 antibody compared with chemotherapy.

Methods: PubMed, Web of Science and the Cochrane Library database were searched for the studies about the efficacy and safety of anti-PD-1/PD-L1 antibody in previously-treated, progressive NSCLC patients. Only randomized controlled trials (RCTs) comparing anti-PD-1/PD-L1 antibody with conventional chemotherapy in NSCLC were included. Overall survival (OS) in the intention-to-treat population was the primary outcome. The secondary outcomes were: progression-free survival (PFS) in the intention-to-treat population, objective response rate (ORR), the incidence of adverse events, OS and PFS in different PD-L1 expression subgroups.

Results: Four trials with a total of 2,174 patients were included. Anti-PD-1/PD-L1 antibody showed a significant benefit to OS in the intention-to-treat population [combined hazard ratio (HR) 0.67; 95% CI: 0.61-0.75, P<0.00001], a 33% reduction in the relative risk of death. PFS also favored anti-PD-1/PD-L1 antibody (HR 0.81, 95% CI: 0.70-0.95, P=0.009). The ORR was significantly higher with anti-PD-1/PD-L1 antibody than those with chemotherapy (RR of nonresponse, 0.92; 95% CI: 0.89-0.95, P<0.00001). Anti-PD-1/PD-L1 antibody was associated with greater efficacy than chemotherapy across the end points of OS and PFS when tumor PD-L1 expression scored ≥1%, ≥5%, and ≥50%, except for tumor PD-L1 expression scored <1%. The group receiving anti-PD-1/PD-L1 antibody had lower rates of treatment-related adverse events of any grade (RR 0.77; 95% CI: 0.73-0.81, P<0.00001) and treatment-related adverse events of grade 3-5 (RR 0.24; 95% CI: 0.14-0.41, P<0.00001).

Conclusions: Anti-PD-1/PD-L1 antibody significantly improved survival compared with chemotherapy in previously-treated, progressive NSCLC patients. Besides, it also had a better safety profile.