Nab-paclitaxel plus S-1 as first-line followed by S-1 maintenance for advanced pancreatic adenocarcinoma: a single-arm phase II trial

PURPOSE: We conducted a single-arm prospective phase II study to determine the efficacy and safety of the first-line treatment of advanced pancreatic cancer with nab-paclitaxel and S-1 followed by S-1 maintenance therapy. METHODS: Nab-paclitaxel was administered intravenously on days 1 and 8 at 120 mg/m(2). S-1 at 120 mg/day (for surface area ≥ 1.5 m(2)), 100 mg/day (for surface area between 1.25–1.5 m(2)), and 80 mg/day (for surface area < 1.25 m(2)) were given two times daily on days 1–14 every 3 weeks. Patients who achieved response and stable disease after 6 cycles were given S-1 maintenance treatment in the same schedule until disease progression or unacceptable toxicity developed. The primary endpoint was objective response rate (ORR), and the secondary endpoints were disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety. Between 01/2015 and 07/2017, 32 patients were enrolled. RESULTS: The ORR in the intention-to-treat (ITT) population (N = 32) was 53.1%, and the DCR was 87.5%. In the 30 evaluable patients, the ORR and DCR were 56.7 and 93.3%, respectively. The median follow-up time was 18 (range 12–36) months, the median PFS was 6.2 (range 4.4–8) months, and the median OS was 13.6 (range 8.7–18.5) months. The incidence of grade 3/4 neutropenia was 27.6%. Other grade 3 adverse events included 1 (3.1%) hand–foot syndrome, 1 (3.1%) rash and 2 (6.3%) diarrheas. CONCLUSIONS: Nab-paclitaxel and S-1 regimen has presented encouraging ORR, OS, and manageable toxicities as first-line therapy for advanced pancreatic cancer.