Malignant pleural effusion as a predictor of the efficacy of anti-PD-1 antibody in patients with non-small cell lung cancer.

BACKGROUND: The aim of this study was to evaluate the usefulness of the presence of malignant pleural effusion (MPE) as a negative predictor of anti-PD-1 antibody efficacy.

METHODS: A retrospective review of patients with advanced or recurrent non-small cell lung cancer treated with an anti-PD-1 antibody between December 2015 and March 2018 at the National Cancer Center Hospital, Japan, was conducted. Progression-free survival (PFS) and overall survival (OS) were compared between patients with and without MPE. Additional survival analysis according to PD-L1 expression status was conducted. Univariate and multivariate analyses were performed.

RESULTS: A total of 252 patients were identified before the commencement of anti-PD-1 antibody treatment: 33 with MPE and 219 without MPE. PFS and OS were significantly shorter in patients with MPE than in patients without MPE (median PFS 3.0 vs. 5.8 months, hazard ratio [HR] 1.7, P = 0.014; median OS 7.9 vs. 15.8 months, HR 2.1, P = 0.001). In patients with PD-L1 expression in ≥ 1% of their tumor cells, the PFS of patients with MPE was significantly shorter than of patients without MPE (median PFS 3.1 vs. 6.5 months, HR 2.0, 95% confidence interval 1.0-3.5; P = 0.021). The presence of MPE was independently associated with a shorter PFS and OS in multivariate analysis.

CONCLUSION: The presence of MPE in patients administered an anti-PD-1 antibody is associated with shorter PFS and OS, regardless of the presence of PD-L1 expression ≥ 1% of tumor cells.