A retrospective comparative study of S-IROX and modified FOLFIRINOX for patients with advanced pancreatic cancer refractory to gemcitabine plus nab-paclitaxel

Purpose: The aim of this study was to evaluate the efficacy and tolerability of S-IROX and modified FOLFIRINOX (mFFX) after gemcitabine plus nab-paclitaxel for advanced pancreatic cancer (PC) in the real world setting. Methods: Consecutive patients receiving S-IROX or mFFX as a second-line chemotherapy for advanced PC refractory to gemcitabine plus nab-paclitaxel were retrospectively studied. Patients were treated every 2 weeks: S-1 40 mg/m² was administered orally twice daily on days 1 to 7 in S-IROX and 5-fluorouracil 2400 mg/m² was intravenously administered for 46 h without bolus infusion in mFFX, in addition to intravenous oxaliplatin 85 mg/m² and irinotecan 150 mg/m² on day 1 in both regimens. Results: Fifty-four patients with advanced PC who received S-IROX (n = 19) or mFFX (n = 35) were retrospectively studied. The disease control rate and response rate were 73.7% and 10.5% in the S-IROX group and 62.2% and 2.7% in the mFFX group, respectively. The median progression free survival (PFS) was 7.8 and 5.7 months in the S-IROX and mFFX groups (p = 0.24). The median overall survival (OS) was 14.2 and 11.5 months in the S-IROX and mFFX groups (p = 0.34). There were no significant differences in the incidences of grade 3–4 adverse effects. The subgroup analyses suggested S-IROX demonstrated favorable OS in patients with PFS ≥6 months of first-line gemcitabine plus nab-paclitaxel (p for interaction = 0.02). Conclusions: S-IROX and mFFX were similarly tolerable and effective as a second-line chemotherapy in patients with PC refractory to gemcitabine plus nab-paclitaxel.