Adding-on nivolumab to chemotherapy-stabilized patients is associated with improved survival in advanced pancreatic ductal adenocarcinoma.

Background: Immune checkpoint inhibitors (ICIs) are rarely used to treat advanced pancreatic ductal adenocarcinoma (PDAC) due to marginal efficacy.

Patients and methods: This study included 92 consecutive patients diagnosed with advanced or recurrent PDAC who received nivolumab-based treatment. Univariate and multivariate analyses were used to identify prognostic factors. A control group of 301 patients with PDAC who achieved disease control with palliative chemotherapy but without ICIs was selected for comparison using propensity score matching (PSM).

Results: The median overall survival (OS) since nivolumab treatment was 15.8 (95% confidence interval [CI], 12.5-19.0), 2.4 (95% CI 1.2-3.6), and 1.1 (95% CI 1.0-1.2) months in patients who received add-on nivolumab after achieving disease control with chemotherapy, in those who received concomitant nivolumab and chemotherapy without prerequisite confirmation of disease control, and in those who received nivolumab without concomitant chemotherapy, respectively (P < 0.001). After PSM, the median overall survival (OS) since initiation of the concomitant chemotherapy that achieved disease control was significantly longer (P = 0.026) in patients who received add-on nivolumab (19.8 months; 95% CI 14.5-25.1) than in those who received chemotherapy alone (13.8 months; 95% CI 10.8-16.9). The immune profiling of the tumors in resected patients revealed higher scores of CD8⁺ T cells to Tregs in patients with add-on nivolumab comparing to those who received chemotherapy alone.

Conclusion: Adding-on nivolumab was associated with improved OS in patients with advanced PDAC who achieved disease control following chemotherapy.