RESUMEN
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy characterized by abundant granulocytic myeloid-derived suppressor cells (G-MDSC = CD45+/Lin-/CD33+/CD11b+/CD15+), which infiltrate tumors and suppress anti-tumor immunity. We have previously demonstrated in a murine model of PDAC that zoledronic acid (ZA) depletes G-MDSC resulting in decreased tumor growth and improved survival. We report here the results of a phase 1 clinical trial (NCT00892242) using ZA as neo-adjuvant, perioperative therapy in patients with non-metastatic, resectable pancreatic adenocarcinoma. METHODS: Eligible PDAC patients received ZA (4mg) IV 2 weeks prior to surgery. Patients then received 2 additional doses of ZA 4 weeks apart. Blood and bone marrow were obtained from patients prior to treatment with ZA and 3 months after surgery for analysis of G-MDSC by flow cytometry. RESULTS: Twenty-three patients received pre-operative ZA with at least 6 months of follow-up Only 15 PDAC patients had non-metastatic PDAC, which was amenable to resection. ZA was well tolerated, and all adverse events were grade 1 or 2. The most common adverse events were fatigue, abdominal pain/discomfort, anorexia, and arthralgia. Of resected PDAC patients treated with ZA, 1- and 2-year overall survival (OS) was 85.7% and 33.3%, respectively, with a median OS of 18 months. This group had a 1- and 2-year progression-free survival (PFS) of 26.9% and 8.9%, respectively, with a median PFS of 12 months. The prevalence of G-MDSC was unchanged in the blood and bone marrow of PDAC patients pre- and post-treatment with ZA. CONCLUSION: ZA is safe and well tolerated as neo-adjuvant, peri-operative therapy in PDAC patients. In this small study, we did not observe a difference in OS or PFS compared to historical controls. Also, there was no difference in the prevalence of G-MDSC in the blood and bone marrow of PDAC patients pre- and post-treatment with ZA.
RESUMEN
PURPOSE: To determine the role of the CCL2/CCR2 axis and inflammatory monocytes (CCR2(+)/CD14(+)) as immunotherapeutic targets in the treatment of pancreatic cancer. EXPERIMENTAL DESIGN: Survival analysis was conducted to determine if the prevalence of preoperative blood monocytes correlates with survival in patients with pancreatic cancer following tumor resection. Inflammatory monocyte prevalence in the blood and bone marrow of patients with pancreatic cancer and controls was compared. The immunosuppressive properties of inflammatory monocytes and macrophages in the blood and tumors, respectively, of patients with pancreatic cancer were assessed. CCL2 expression by human pancreatic cancer tumors was compared with normal pancreas. A novel CCR2 inhibitor (PF-04136309) was tested in an orthotopic model of murine pancreatic cancer. RESULTS: Monocyte prevalence in the peripheral blood correlates inversely with survival, and low monocyte prevalence is an independent predictor of increased survival in patients with pancreatic cancer with resected tumors. Inflammatory monocytes are increased in the blood and decreased in the bone marrow of patients with pancreatic cancer compared with controls. An increased ratio of inflammatory monocytes in the blood versus the bone marrow is a novel predictor of decreased patient survival following tumor resection. Human pancreatic cancer produces CCL2, and immunosuppressive CCR2(+) macrophages infiltrate these tumors. Patients with tumors that exhibit high CCL2 expression/low CD8 T-cell infiltrate have significantly decreased survival. In mice, CCR2 blockade depletes inflammatory monocytes and macrophages from the primary tumor and premetastatic liver resulting in enhanced antitumor immunity, decreased tumor growth, and reduced metastasis. CONCLUSIONS: Inflammatory monocyte recruitment is critical to pancreatic cancer progression, and targeting CCR2 may be an effective immunotherapeutic strategy in this disease.
