Fruquintinib and Albumin-paclitaxel Combined With or Without PD-1 Antibody in 2nd-line Treatment of G/GEJ Adenocarcinoma

Inclusion Criteria:

1. Have fully understood the study and voluntarily signed the informed consent;

2. Age ≥18 years old;

3. Pathologically confirmed advanced gastric/gastroesophageal junction adenocarcinomawith at least one systemic treatment;

4. Frontline experienced exposure to immune drugs (including exposure to PD-1 drugs inthe neoadjuvant, adjuvant, and systemic treatment stages; For patients withmetastasis and recurrence within 6 months after the end of adjuvant/neoadjuvantsystem treatment, the above-mentioned treatment is first-line treatment);

5. ECOG's physical condition was 0-1, and did not deteriorate within 7 days;

6. BMI≥18;

7. Expected survival ≥3 months;

8. The functions of vital organs meet the following requirements (the use of any bloodcomponents and cell growth factors is not allowed within the first 14 days ofenrollment) a) Absolute neutrophil count ≥1.5×109/L, white blood cell ≥4.0×109/L; b)Platelet ≥100×109/L; c) Hemoglobin ≥90g/L; d) Total bilirubin TBIL≤1.5 times ULN;e)ALT and AST≤2.5 times ULN (up to 5 times in patients with liver metastasis); f)Urea/urea nitrogen (BUN) and creatinine (Cr) ≤1.5×ULN (and creatinine clearance (CCr) ≥ 50mL/min); g) Left ventricular ejection fraction (LVEF) ≥50%; h)Fridericia'scorrected QT interval (QTcF) <470 ms. i) INR≤1.5 x ULN, APTT≤1.5 x ULN.

9. Women of childbearing age need to take effective contraceptive measures;

10. Good compliance, cooperate with follow-up;

Exclusion Criteria:

1. Failure to comply with the study protocol or study procedure;

2. Previous treatment with VEGFR inhibitors;

3. Previously received paclitaxel therapy (except for those who received paclitaxeltherapy in neoadjuvant or adjuvant therapy, and the treatment ended more than 6months after the progression of the disease);

4. Known HER-2 positive patients;

5. Receive live vaccine within 4 weeks prior to enrollment or possibly during the studyperiod;

6. Had other malignancies within 5 years prior to enrollment, except basal cell orsquamous cell carcinoma of the skin after radical surgery, or carcinoma in situ ofthe cervix;

7. Had active autoimmune disease or history of autoimmune disease within 4 weeks priorto enrollment;

8. Previously received allogeneic bone marrow transplantation or organ transplantation;

9. Subjects who are allergic to the investigational drug or any of its adjuncts;

10. Electrolyte abnormalities identified by the investigator as clinically significant;

11. Hypertension that could not be controlled by drugs before enrollment was defined as:systolic blood pressure ≥150 mmHg and/or diastolic blood pressure ≥90 mmHg;

12. Had any disease or condition affecting drug absorption before enrollment, or thepatient could not take the drug orally;

13. Gastrointestinal diseases such as active ulcer of stomach and duodenum, ulcerativecolitis, or active bleeding of unresectable tumors, or other conditions that maycause gastrointestinal bleeding or perforation as determined by researchers beforeenrollment;

14. Patients with significant evidence or history of bleeding tendency (hemorrhage >30mL within 3 months, accompanied by hematemesis, stool, and blood in the stool),hemoptysis (>5 mL of fresh blood within 4 weeks), or thromboembolic events (including stroke events and/or transient ischemic attacks) within 12 months priorto enlistment;

15. Clinically significant cardiovascular disease, including but not limited to acutemyocardial infarction, severe/unstable angina pectoris, or coronary artery bypassgrafting within 6 months prior to enrollment; Congestive heart failure New YorkHeart Association (NYHA) Grade >2; Ventricular arrhythmias requiring medicaltreatment; LVEF (left ventricular ejection fraction) <50%;

16. Active or uncontrolled severe infection (≥CTCAE v5.0 grade 2 infection);

17. Known human immunodeficiency virus (HIV) infection. A known history of clinicallysignificant liver disease, including viral hepatitis [active HBV infection, i.e.,positive HBV DNA (>1×104 copies /mL or >2000 IU/ml) must be excluded for a knownhepatitis B virus (HBV) carrier; Known hepatitis C virus infection (HCV) and HCV RNApositive (>1×103 copies /mL);

18. Unmitigated toxicity higher than CTCAE v5.0 grade 1 due to any previous anticancertherapy, excluding alopecia, lymphocytopenia, and oxaliplatin grade ≤2neurotoxicity;

19. Women who are pregnant (positive pregnancy test before medication) or breastfeeding;

20. Received blood transfusion therapy, blood products and hematopoietic factors, suchas albumin and granulocyte colony-stimulating factor (G-CSF), within 28 days beforeenrollment;

21. Any other medical condition, clinically significant metabolic abnormality, physicalabnormality or laboratory abnormality, which, in the investigator's judgment,reasonably suspects that the patient has a medical condition or condition that isnot suitable for the use of the investigational drug (such as having seizures andrequiring treatment), or which would affect the interpretation of the study resultsor place the patient at high risk;

22. Urine routine indicated urinary protein ≥2+, and 24-hour urinary protein volume >1.0g;

23. The patients considered by the investigators to be unsuitable for inclusion in thisstudy.