The safety and efficacy of anti-PD-1/PD-L1 monoclonal antibodies for lung cancer brain metastasis: a systematic review and meta-analysis on brain metastasis

Individuals with non-small cell lung cancer (NSCLC) who develop brain metastases face a poor prognosis and limited treatment options. Programmed cell death protein 1 (PD-1) inhibitors, such as pembrolizumab and nivolumab, have emerged as a promising immunotherapy for treating lung cancer with brain metastases. This systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline and evaluate the safety and efficacy of anti-PD-1/PD-L1 monoclonal antibodies in treating lung cancer patients with brain metastases. A comprehensive literature search was conducted to identify relevant studies up to 27 August 2023. Data on overall survival (OS), progression-free survival, radiological response rates, and adverse events were extracted. All statistical analysis was performed using STATA v.17. Our literature search yielded 39 eligible studies involving 15,428 patients. The overall response rate for PD-1 inhibitors was substantial, with pooled rates of 39% for overall response, 7% for complete response (CR), 27% for partial response (PR), and 31% for stable disease (SD). The pooled 6-month OS rate was 77%, and the 1-year OS rate was 61%. Subgroup analyses revealed higher PD-L1 expression levels and the use of platinum-based chemotherapy alongside immunotherapy were associated with improved outcomes. PD-1/PD-L1 inhibitors have demonstrated promising efficacy and safety in treating lung cancer patients with brain metastases, as evidenced by significant improvements in OS, PFS, and response rates. Incorporating PD-1/PD-L1 inhibitors into the treatment regimen, particularly for patients with high PD-L1 expression, has the potential to improve clinical outcomes in this patient population.