Liposomal irinotecan, oxaliplatin, and S-1 as first-line therapy for patients with locally advanced or metastatic pancreatic adenocarcinoma (NASOX): A multicenter phase I/IIa study.

Introduction: This multicenter phase I/IIa study aimed to determine the recommended phase II dose (RP2D) and evaluate the safety and preliminary efficacy of liposomal irinotecan (nal-IRI), oxaliplatin, and S-1 (NASOX) as first-line treatment for advanced pancreatic adenocarcinoma.

Methods: Patients with locally advanced or metastatic pancreatic adenocarcinoma without prior systemic treatment for advanced disease, aged ≥ 19 years, with measurable disease, and Eastern Cooperative Oncology Group performance status of 0-1 were eligible. The primary endpoints were to determine the dose-limiting toxicity (DLT) in the phase I cohort and overall response rate (ORR) in the phase IIa cohort. The intention-to-treat (ITT) analysis included patients who received the RP2D.

Results: In phase I, seven patients were screened, and six were assessed for DLT. None experienced DLT during the first cycle. The RP2D was determined as nal-IRI 50 mg/m and oxaliplatin 60 mg/m on day 1, S-1 40 mg/m twice daily on days 1-7 every 14 days. For the ITT (N = 41; 7, and 34 from phases I and IIa, respectively), the most common grade 3-4 treatment-emergent adverse events were neutropenia (31.7 %), enterocolitis (9.8 %), anorexia (7.3 %), and diarrhea (2.4 %). The ORR was 58.5 % (1 complete, and 23 partial responses). Two underwent conversion surgery; both achieved R0 resection. With median follow-up of 17.5 months, median progression-free survival was 6.5 months (95 % confidence interval [CI], 5.0-8.1) and median overall survival was 11.4 months (95 % CI, 9.8-15.5).

Conclusion: NASOX exhibited a manageable safety profile and encouraging efficacy outcomes consistent with NALIRIFOX, showing potential to replace infusional 5-fluorouracil with oral S-1 in the triplet regimen.