Modified FOLFIRINOX versus S-1 as second-line chemotherapy in patients with gemcitabine-failed metastatic pancreatic cancer: A randomized phase III trial (MPACA-3).

4119 Background: Modified FOLFIRINOX (mFOLFIRINOX) consisting of 5-fluorouracil/leucovorin, irinotecan, and oxaliplatin has been assessed as second-line treatment of patients with advanced pancreatic cancer in retrospective and phase II studies. However, the result was not confirmed by randomized controlled trial. Methods: A randomized, open-label, phase III trial was conducted at 9 institutions in Korea. Patients with metastatic pancreatic adenocarcinoma (mPAC) and Eastern Cooperative Oncology Group performance status of 0-1 who failed to first-line gemcitabine-based chemotherapy were randomly assigned to receive mFOLFIRINOX or S-1. The primary endpoint was overall survival. Results: A total of 80 patients were enrolled from March 2017 to December 2019. The accrual of patients was early terminated due to clear difference of efficacy in the interim analysis and expectation of poor recruitment due to conflicting adjuvant regimens. Objective response and disease control rates were 15.4% vs. 2.4% ( p= 0.041) and 66.7% vs. 36.6% ( p= 0.007) in the mFOLFIRINOX and S-1 arms, respectively. The median progression-free survival was 5.2 and 2.2 months in the mFOLFIRINOX and S-1 arms, respectively ( p= 0.002). The median overall survival was 9.2 and 4.9 months in the mFOLFIRINOX and S-1 arms, respectively ( p= 0.048). The adjusted hazard ratio of the mFOLFIRINOX arm to the S-1 arm for overall survival was 0.402 (95% confidence interval 0.223-0.725, p= 0.002). All grade 3-4 adverse events occurred in 56.5% and 17.1% in the mFOLFIRINOX and S-1 arms, respectively ( p< 0.001). However, only one patient in each arm prematurely discontinued treatment due to toxicity and there was no treatment-related mortality in both arms. Minimally important differences in the health-related quality of life were not observed in both arms. Conclusions: mFOLFIRINOX as second-line treatment in mPAC patients failed to gemcitabine-based chemotherapy demonstrated a survival benefit versus S-1 alone with acceptable toxicities. Clinical trial information: KCT0003534.