Cisplatin to Patients With Pancreatic Cancer and Homologous Recombination Deficiency

Pancreatic adenocarcinoma (PDAC) is a highly lethal malignancy with a 5-year survival less than 10%. Approximately 80% of patients with pancreatic cancer are diagnosed at an advanced stage. Chemotherapy is one of the major treatments for advanced pancreatic cancer. In 2011, the PRODIGE trial has shown that oxaliplatin, irinotecan, fluorouracil, and leucovorin (FOLFIRINOX) was associated with a survival advantage but had increased toxicity. Defects in DNA damage response (DDR) genes causing homologous recombination deficiency (HRD) identify a clinically relevant subgroup of patients with PDAC, with both therapeutic and preventative implications. Accumulating evidence from nonrandomized and randomized clinical trials suggests HRD as a putative biomarker of therapeutic response for platinum-based chemotherapy in patients with advanced PDAC. Within HRD, germline variants in BRCA1 and BRCA2 are associated with improved progression-free survival in patients with platinum-sensitive metastatic PDAC treated with the poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi) olaparib as maintenance therapy. Interestingly, based on preclinical evidence and phase II nonrandomized clinical trials, additional non-BRCA HRD aberrations may predict sensitivity to PARPi with other therapeutic strategies targeting DDR currently under clinical investigation (including immunotherapy, ATM, ATR, and PALB2 inhibitors). However, the efficacy of cisplatin based regimen as a second line treatment for patients with HRD has not been systematically studied. The purpose of this study is to evaluate the efficacy of cisplatin based regimen on improving the progression-free survival (PFS) of advanced pancreatic cancer patients who harbor germline or somatic homologous recombination deficiency. These patients are resistant to at least one line of systemic chemotherapy. PFS, objective response rate (ORR), overall survival (OS) and disease control rate (DCR) are measured every four weeks.