Deleterious alterations in DNA-damage repair (daDDR) genes as a predictive biomarker for platinum-based chemotherapy in metastatic pancreatic ductal adenocarcinoma (mPDAC).

266Background: Germline genetic testing and somatic genomic profiling using commercial multigene panels are now routine in mPDAC. A subset of these patients have deleterious alterations in genes involved with DDR. Herein we investigate the role of daDDR as a predictive biomarker for response to first-line platinum-based chemotherapy. Methods: Utilizing the IRB-approved pancreas cancer and genetics clinic databases at the University of Miami, we identified all patients with mPDAC who had germline and/or somatic mutation testing. We performed a retrospective chart review to extract demographic and clinical characteristics including treatments received, response and survival. Results: Between 2012 and 2018, 116 patients with mPDAC underwent germline (using Invitae, Ambry Counsyl or Myriad) and/or somatic testing (using FoundationOne CDx). Among these, 40 received first-line therapy with FOLFIRINOX (95%) or gemcitabine/cisplatin (5%). The median age was 59 years and 15 (38%) were female. The majority (70%) we...