Efficacy of Preoperative mFOLFIRINOX vs mFOLFIRINOX Plus Hypofractionated Radiotherapy for Borderline Resectable Adenocarcinoma of the Pancreas: The A021501 Phase 2 Randomized Clinical Trial

Importance: National guidelines endorse treatment with neoadjuvant therapy for borderline resectable pancreatic ductal adenocarcinoma (PDAC), but the optimal strategy remains unclear. Objective: To compare treatment with neoadjuvant modified FOLFIRINOX (mFOLFIRINOX) with or without hypofractionated radiation therapy with historical data and establish standards for therapy in borderline resectable PDAC. Design, Setting, and Participants: This prospective, multicenter, randomized phase 2 clinical trial conducted from February 2017 to January 2019 among member institutions of National Clinical Trials Network cooperative groups used standardized quality control measures and included 126 patients, of whom 70 (55.6%) were registered to arm 1 (systemic therapy; 54 randomized, 16 following closure of arm 2 at interim analysis) and 56 (44.4%) to arm 2 (systemic therapy and sequential hypofractionated radiotherapy; all randomized before closure). Data were analyzed by the Alliance Statistics and Data Management Center during September 2021. Interventions: Arm 1: 8 treatment cycles of mFOLFIRINOX (oxaliplatin, 85 mg/m²; irinotecan, 180 mg/m²; leucovorin, 400 mg/m²; and infusional fluorouracil, 2400 mg/m²) over 46 hours, administered every 2 weeks. Arm 2: 7 treatment cycles of mFOLFIRINOX followed by stereotactic body radiotherapy (33-40 Gy in 5 fractions) or hypofractionated image-guided radiotherapy (25 Gy in 5 fractions). Patients without disease progression underwent pancreatectomy, which was followed by 4 cycles of treatment with postoperative FOLFOX6 (oxaliplatin, 85 mg/m²; leucovorin, 400 mg/m²; bolus fluorouracil, 400 mg/m²; and infusional fluorouracil, 2400 mg/m²over 46 hours). Main Outcomes and Measures: Each treatment arm's 18-month overall survival (OS) rate was compared with a historical control rate of 50%. A planned interim analysis mandated closure of either arm for which 11 or fewer of the first 30 accrued patients underwent margin-negative (R0) resection. Results: Of 126 patients, 62 (49%) were women, and the median (range) age was 64 (37-83) years. Among the first 30 evaluable patients enrolled to each arm, 17 patients in arm 1 (57%) and 10 patients in arm 2 (33%) had undergone R0 resection, leading to closure of arm 2 but continuation to full enrollment in arm 1. The 18-month OS rate of evaluable patients was 66.7% (95% CI, 56.1%-79.4%) in arm 1 and 47.3% (95% CI 35.8%-62.5%) in arm 2. The median OS of evaluable patients in arm 1 and arm 2 was 29.8 (95% CI, 21.1-36.6) months and 17.1 (95% CI, 12.8-24.4) months, respectively. Conclusions and Relevance: This randomized clinical trial found that treatment with neoadjuvant mFOLFIRINOX alone was associated with favorable OS in patients with borderline resectable PDAC compared with mFOLFIRINOX treatment plus hypofractionated radiotherapy; thus, mFOLFIRINOX represents a reference regimen in this setting. Trial Registration: ClinicalTrials.gov Identifier: NCT02839343.