The optimal neoadjuvant therapy for resectable pancreatic ductal adenocarcinoma (PDA) and the impact on surgical outcomes remains unclear.

S1505 (NCT02562716) was a randomized phase II study of perioperative chemotherapy with mFOLFIRINOX (Arm 1) or gemcitabine/nab-paclitaxel (Arm 2). Measured parameters included resection rate, margin positivity, pathologic response, and toxicity.

Between 2015 and 2018, 147 patients were randomized. Of these, 44 (30%) were deemed ineligible (43 by central review). Of the 103 eligible patients, 77 (76%) completed preoperative therapy and underwent surgery; reasons patients did not undergo surgery included toxicity related to preoperative therapy (n = 9), progression (n = 9), or other (n = 7). Of the 77, 73 (95%) underwent successful resection; 21 (29%) required vascular reconstruction, 62 (85%) had negative (R0) margins, and 24 (33%) had a complete or major pathologic response to therapy. The grade 3-5 postoperative complication rate was 16%. Of the 73 patients completing surgery, 57 (78%) started and 46 (63%) completed postoperative therapy. This study represents the first prospective trial evaluating modern systemic therapy delivered in a neoadjuvant/perioperative format for resectable PDA.

We have demonstrated: (1) Based on the high percentage of enrolled, but ineligible patients, it is clear that adherence to strict definitions of resectable PDA is challenging; (2) Patients can tolerate modern systemic therapy and undergo successful surgical resection without prohibitive perioperative complications; (3) Completion of adjuvant therapy in the perioperative format is difficult; (4) Major pathologic response rate of 33% is encouraging.