- The dense desmoplastic mesenchymal network that constitutes the stroma of pancreatic adenocarcinomas coupled with poor vascularity may present a major challenge to effective delivery of intravenous chemotherapy to the bulk of pancreatic tumor cell burden. Recent evidence in a genetically engineered mouse model of pancreatic cancer demonstrated that IPI-926 can deplete tumor-associated stromal tissue and increase intratumoral mean vessel density, resulting in enhanced delivery of concurrently administered systemic agents such as gemcitabine, decreased tumor burden, and prolonged survival.(33)