Immunotherapy based on anti PD-1/PD-L1 inhibitors is the new standard of advanced non-small cell lung cancers. Pembrolizumab, nivolumab and atezolizumab are used in clinical practice. The strict eligibility criteria of clinical trials do not allow researchers to fully represent treatment effects in the patients that will ultimately use these drugs. We performed a systematic review and a meta-analysis to evaluate the effectiveness and safety of these drugs, and more generally of ICIs, as second-line therapy in NSCLC patients in real world practice. MEDLINE, PubMed, Scopus and Web of Science were searched to include original studies published between January 2015 and April 2020. A total of 32 studies was included in the meta-analysis. The overall radiological response rate (ORR), disease control rate (DCR), median progression-free survival (PFS) and overall survival (OS) were 21%, 52%, 3.35 months and 9.98 months, respectively. The results did not change when analysis was adjusted for Eastern Cooperative Oncology Group performance status (ECOG PS) and age. A unitary increase in the percent of patients with liver and CNS metastases reduced the occurrence of DCR by 7% (p < 0.001) and the median PFS by 2% (p = 0.010), respectively. The meta-analysis showed that the efficacy and safety of immunotherapy in everyday practice is comparable to that in clinical trials.
Keywords: NSCLC; atezolizumab; efficacy; immune checkpoint inhibitors; immunotherapy; nivolumab; non-small cell lung cancer; pembrolizumab; real-life; safety.