Sirolimus for Injection (Albumin Bound) Combined With Octreotide Long-acting Injection in Patients With Metastatic Gastroenteropancreatic Neuroendocrine Tumors

Inclusion Criteria: * 1\. Unresectable locally advanced or metastatic G1/G2 GEP-NETs diagnosed by histology, according to the 2019 WHO histological grading criteria. * 2\. Having poor prognostic factors. * 3\. Non-functional GEP-NETs are required. * 4\. At least one evaluable lesion meets the RECIST V1.1 standard (Applicable only to the phase II safety run-in stage) * 6\. ECOG 0\~2. * 7\. Organ function reserve is good. * 8\. Be able to sign a written informed consent form. Exclusion Criteria: * 1\. Patients who have previously received SSTR-targeted therapies (including somatostatin analogs \[SSAs\] and peptide receptor radionuclide therapy) and/or mTOR inhibitors (Patients who received SSAs in the adjuvant setting and experienced recurrence ≥6 months after treatment completion may be enrolled)\[ Applicable to Phase II dose expansion and Phase III stages\]. * 2\. Has uncontrolled/severe diarrhea or an axillary temperature \> 38.0°C at enrollment. * 3\. Received treatment with other unlisted clinical investigational drugs within 4 weeks prior to the first use of the investigational drug. * 4\. Undergone major surgical procedures within 4 weeks prior to the first use of the investigational drug and have not fully recovered. * 5\. Received systemic use of corticosteroids or other immunosuppressive therapy within 2 weeks prior to the first use of the study drug. * 6\. With an infection that requires systemic anti-infective treatment within 2 weeks prior to the first use of the study drug. * 7\. Those who have used strong inhibitors or inducers of CYP3A4 liver metabolic enzymes within 2 weeks prior to the first use of the investigational drug or still need to continue using such drugs. * 8\. Has a serious history of cardiovascular and cerebrovascular diseases. * 9\. Having active brain metastasis and/or malignant meningitis. * 10\. With a history of severe lung diseases. * 11\. During screening, there may be symptomatic gallstones or a history of symptomatic gallstones but no surgical treatment has been performed. * 12\. Abnormal thyroid function during screening. * 13\. Known to have hypersensitivity reactions or intolerance to any component of all investigational drugs or their excipients. * 14\. Active hepatitis B, active hepatitis C virus infection, or active syphilis infection. * 15\. History of autoimmune diseases (excluding tuberous sclerosis), history of immunodeficiency, including HIV testing positive, or other acquired or congenital immunodeficiency diseases, or history of organ transplantation.