Sintilimab in Combination With Surufatinib and Temozolomide in the Advanced Neuroendocrine Carcinoma

After fully informed and signed informed consent, subjects will receive Sintilimab (200mg each fixed dose, once every 21 days) combined with Temozolomide (BSA≤1.7m2; BSA \> 1.7m2 was administered with 300mg, QD, d1-d5, and with Surufatinib (250mg, QD, continuous administration). A treatment cycle of 21 days until disease progression, death, toxicity intolerance or withdrawal of informed consent, with a maximum treatment period of 24 months.