PD-1/PD-L1 inhibitor combined with chemotherapy can improve the survival of non-small cell lung cancer patients with brain metastases

Introduction: Immune checkpoint inhibitor (ICI) monotherapy has limited efficacy in patients with non-small cell lung cancer (NSCLC) and brain metastases (BMs). With the wide use of ICI-based combinations, the efficacy of different ICI combination strategies in patients with NSCLC and BMs needs to be further elucidated. Methods: We retrospectively reviewed 526 patients with non-small cell lung cancer (NSCLC) treated with ICIs from January 2016 to December 2019 in the Shanghai Pulmonary Hospital. Patients with BMs treated with ICIs were further divided into two groups: those with BM prior to the ICI treatment (pBM group), and those with BM after the treatment (aBM group). We assessed intracranial progression-free survival (IPFS), systemic progression-free survival (SPFS), overall survival (OS), intracranial objective response rate (IORR), and intracranial disease control rate (IDCR). Results: We found 77 patients out of 526 with BMs; 69 presented the BMs prior to the ICI treatments and 8 showed BMs after the ICI treatments. In the pBM group, the median IPFS and SPFS were 7.39 months and 5.39 months, respectively. Combination therapy significantly improved both the IPFS (p=0.007) and the SPFS (p=0.007) when compared with monotherapy. Further analysis demonstrated that ICIs combined with chemotherapy significantly improved both the IPFS (p=0.009) and the SPFS (p=0.006) when compared with monotherapy. While ICIs combined with anti-angiogenic therapy improved the SPFS (p=0.005) but not the IPFS (p=0.139). The median OS was 27.43 months for patients in the pBM group. Further analyses suggested that combination treatment also improved the OS when compared with monotherapy (p=0.003). Subgroup analysis results showed that ICIs combined with chemotherapy led to better OS than ICIs monotherapy (p=0.006). Radiotherapy had no significant impact on survival (IPFS p=0.272, OS p=0.142) in the patients of the pBM group. Conclusion: ICIs combined with chemotherapy demonstrated survival benefits over ICI monotherapy in patients with NSCLCs and BMs.