A Phase I/II Open-Label Multicenter Single-Arm Study of FABLOx (Metronomic 5-Fluorouracil Plus nab-Paclitaxel, Bevacizumab, Leucovorin, and Oxaliplatin) in Patients with Metastatic Pancreatic Cancer

Purpose: To evaluate safety and preliminary efficacy of metronomic 5-fluorouracil plus nab-paclitaxel, bevacizumab, leucovorin, and oxaliplatin (FABLOx) in patients with newly diagnosed metastatic pancreatic cancer (MPC). Methods: A total of 12 treatment-naive patients (aged 18–65 years, Eastern Cooperative Oncology Group performance status [ECOG PS] ≤1) with MPC received 5-fluorouracil 180 mg/m(2) per day (days 1–14 continuous infusion); nab-paclitaxel 75 mg/m(2), leucovorin 20 mg/m(2), and oxaliplatin 40 mg/m(2) (days 1, 8, and 15); and bevacizumab 5 mg/kg (days 1 and 15) administered intravenously in each 28-day cycle. The primary end-point was incidence of dose-limiting toxicities (DLTs) in cycle 1. Safety was further evaluated as a secondary end-point; preliminary efficacy was also examined. Results: Two DLTs (grade 3 anemia requiring transfusion and grade 3 mucositis unresponsive to treatment within 4 days of onset) were observed in one of six patients enrolled in dose cohort 1. Cohort 1 was expanded from 6 to 12 patients to further evaluate safety, per the investigators' recommendation. All patients discontinued treatment. The most common grade ≥3 adverse events were abdominal pain, fatigue, mucositis, and decreased neutrophil count. Objective response rate was 33% (four partial responses). Median progression-free survival (PFS) and overall survival (OS) were 5.6 (95% confidence interval [CI], 1.7–11.3) and 9.9 (95% CI, 4.4–13.2) months, respectively; 1-year PFS and OS rates were 12.2% (95% CI, 0.7–40.8) and 38.9% (95% CI, 12.6–65.0). Conclusion: FABLOx is feasible and tolerable in patients newly diagnosed with MPC. However, preliminary efficacy data are inconclusive for continued investigation in a phase II trial.