Background: Data regarding immunotherapy efficacy for patients with metastatic NSCLC and brain metastases (BM) are limited and represent a small subset of the clinical trial population. Phase II studies have demonstrated intracranial efficacy of immune-checkpoint inhibitors (ICI) +/- chemotherapy [1-3]. The efficacy of chemotherapy and ICI combinations compared to ICI alone in patients with metastatic NSCLC with BM remains unknown.
Methods: A systematic review and network meta-analysis were performed (PROSPERO-CRD42024501345). The objective of this study was to evaluate ICI efficacy in metastatic NSCLC and BM and the influence of additional chemotherapy on survival outcomes. Randomised phase II/III studies with at least one treatment arm with an ICI were eligible for inclusion. The target population was treatment-naïve metastatic NSCLC. Efficacy results including OS and PFS in the subpopulation of patients with and without BM were assessed.
Results: Ten studies were included, totalling 6,560 patients, of whom 770 had BM. Pairwise meta-analysis revealed that patients with BM treated with ICI +/- chemotherapy had improved PFS (HR 0.49; 95% CI 0.39-0.60) and OS (HR 0.55; 95%CI 0.44-0.68) versus chemotherapy alone. Patients without BM treated with ICI +/- chemotherapy also improved PFS (HR 0.60; 95% CI 0.52-0.68) and OS (HR 0.72; 95% CI 0.66-0.78).
In the network meta-analysis of patients with BM, combination ICI with chemotherapy demonstrated improved PFS compared to ICI alone (HR 0.64; 95% CI 0.43-0.96; p=0.03). However, no significant difference was observed in OS between the two treatments (HR 0.99; 95% CI 0.56-1.74; p=0.97). Conversely, in the population of patients without BM, no significant differences in either PFS (HR 1.09; 95% CI 0.82-1.44; p=0.56) or OS (HR 0.99; 95% 0.81-1.20; p=0.92) were observed between ICI and chemotherapy group versus ICI alone.
Conclusion: Combination chemoimmunotherapy offers PFS benefit over ICI in BM patients, warranting direct comparisons in clinical trials.