NALIRIFOX as Second-Line Chemotherapy in Extrapulmonary High-grade Neuroendocrine Neoplasms: a Prospective, Single-center, Single-arm Trial

High-grade neuroendocrine neoplasms (NENs) comprise both well-differentiated grade 3 neuroendocrine tumors (G3 NETs) and poorly differentiated neuroendocrine carcinomas (NECs). Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) nearly always include poorly differentiated NEC as the neuroendocrine component. Liposomal irinotecan hydrochloride and NALIRIFOX (liposomal irinotecan hydrochloride with fluorouracil and oxaliplatin) obtained a significant breakthrough in pancreatic cancer treatment. While the efficacy and safety of NALIRIFOX has never been investigated in patients with extrapulmonary high-grade NENs. Investigators conducted a two-stage, prospective, single-center, single-arm trial which enrolled patients with extrapulmonary advanced high-grade NENs who failure of first-line treatment. The primary endpoint is 6-moth disease-free survival. The second endpoint is disease control rate. Investigators will enroll 12 patients in first stage. If more than 6 patients reach 6-moth disease-free survival, the research enters the next stage. Investigators will enroll 28 patients in total, and if more than 19 patients reach the primary endpoint, investigators will further design the phase III clinical trail.