Biomarkers for predicting tumor response to PD-1 inhibitors in patients with advanced pancreatic cancer.

Pancreatic cancer is among the most lethal malignant neoplasms, and few patients with pancreatic cancer benefit from immunotherapy. We retrospectively analyzed advanced pancreatic cancer patients who received PD-1 inhibitor-based combination therapies during 2019-2021 in our institution. The clinical characteristics and peripheral blood inflammatory markers (neutrophil-to-lymphocyte ratio [NLR], platelet-to-lymphocyte ratio [PLR], lymphocyte-to-monocyte ratio [LMR], and lactate dehydrogenase [LDH]) were collected at baseline. Chi-squared and Fisher's exact tests were used to evaluate relationships between the above parameters and tumor response. Cox regression analyses were employed to assess the effects of baseline factors on patients' survival and immune-related adverse events (irAEs). Overall, 67 patients who received at least two cycles of PD-1 inhibitor were considered evaluable. A lower NLR was independent predictor for objective response rate (38.1% vs. 15.2%, P = .037) and disease control rate (81.0% vs. 52.2%, P = .032). In our study population, patients with lower LDH had superior progression-free survival (PFS) and overall survival(OS) (mPFS, 5.4 vs. 2.8 months, P < .001; mOS, 13.3 vs. 3.6 months, P < .001). Liver metastasis was verified to be a negative prognostic factor for PFS (2.4 vs. 7.8 months, P < .001) and OS (5.7 vs. 18.0 months, P < .001). The most common irAEs were hypothyroidism (13.4%) and rash (10.5%). Our study demonstrated that the pretreatment inflammatory markers were independent predictors for tumor response, and the baseline LDH level and liver metastasis were potential prognostic markers of survival in patients with pancreatic cancer treated with PD-1 inhibitors.