Response to PARP Inhibitor in PALB2-Mutated Metastatic Pancreatic Adenocarcinoma: A Case Report

PALB2 (Partner and Localizer of Breast Cancer Type 2 (BRCA2)) pathogenic variants increase sensitivity to poly (ADP-ribose) Polymerase Inhibitors (PARPi) in a variety of malignancies, yet no documented objective response to treatment in metastatic pancreatic cancer has been reported. We describe a case of a PALB2-mutated metastatic pancreatic cancer patient who had achieved a partial response to platinum-based chemotherapy, and was then observed to achieve an ongoing partial response with a further 42% reduction in tumor size over 6-months of treatment to date whilst on the PARPi olaparib.