Aim: At present three immune checkpoint inhibitors (ICIs), two anti-PD-1 (nivolumab and pembrolizumab) and one anti-PD-L1 (atezolizumab) can be used in pretreated non-small-cell lung cancer patients. The aim of this meta-analysis is an indirect comparison between anti-PD-1 and anti-PD-L1 inhibitors. Methods: Seven studies (>4000 patients) were considered. Results: Considering the overall survival ICIs showed very robust efficacy over docetaxel, while in terms of progression-free survival the therapy with ICIs is slightly favored. Anti-PD-1 gives a more significant benefit than anti-PD-L1; however, excluding the KEYNOTE 010 trial that enrolled only PD-L1-positive patients, the subgroup difference remains only in terms of progression-free survival. Conclusion: This meta-analysis confirms the superiority of ICIs over docetaxel in pretreated non-small-cell lung cancer patients and would indicate a slight benefit from anti-PD-1 than from anti-PD-L1 inhibitors, always keeping in mind the possible biases of this indirect comparison.
Keywords: atezolizumab; avelumab; checkpoint inhibitors; immunotherapy; meta-analysis; nivolumab; non-small-cell lung cancer; pembrolizumab.