Towards an optimal treatment algorithm for metastatic pancreatic ductal adenocarcinoma (PDA)

Chemotherapy remains the mainstay of treatment for advanced pancreatic ductal adenocarcinoma (PDA). Two randomized trials have demonstrated superiority of the combination regimens FOLFIRINOX (5-fluorouracil, leucovorin, oxaliplatin, and irinotecan) and gemcitabine plus nab-paclitaxel over gemcitabine monotherapy as a first-line treatment in adequately fit subjects. Selected PDA patients progressing to first-line therapy can receive second-line treatment with moderate clinical benefit. Nevertheless, the optimal algorithm and the role of combination therapy in second-line are still unclear. Published second-line PDA clinical trials enrolled patients progressing to gemcitabine-based therapies in use before the approval of nab-paclitaxel and FOLFIRINOX. The evolving scenario in second-line may affect the choice of the first-line treatment. For example, nanoliposomal irinotecan plus 5-fluouracil and leucovorin is a novel second-line option which will be suitable only for patients progressing to gemcitabine-based therapy. Therefore, clinical judgement and appropriate patient selection remain key elements in treatment decision. In this review, we aim to illustrate currently available options and define a possible algorithm to guide treatment choice. Future clinical trials taking into account sequential treatment as a new paradigm in PDA will help define a standard algorithm.