This study will evaluate the efficacy, safety and tolerability of Surufatinib + Temozolomide + Sintilimab in subjects. 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. Efficacy evaluation was performed at the end of every 2 treatment cycles. After termination of study treatment, participants will be followed up for safety and survival (survival follow-up every 90 days).
The subjects voluntarily joined the study, signed the informed consent, and the compliance was good;
Locally advanced unresectable or metastatic neuroendocrine carcinoma confirmed by histopathology or cytology (excluding small cell lung cancer);
Disease progression or toxicity intolerance after previous first-line and above treatment;
At least one measurable lesion according to RECIST v1.1;
Previous exposure to any anti-PD-1 /PD-L1/PD-L2/CTLA-4 antibody, VEGF/VEGFR targeting drugs;
Previous treatment with temozolomide;
Received chemotherapy, targeted therapy, Chinese herbal medicine with anti-tumor indications, or immunomodulatory drugs within 4 weeks prior to enrollment, or remained within 5 half-lives of such drugs;
Known to be allergic to any monoclonal antibody, temozolomide preparations, and solfantinib preparations;