≥18 years old, ≤75 years old.

Histologically or cytologically confirmed gastric adenocarcinoma, locally advanced and unresectable, local recurrence (local lymph node metastasis) or distant metastasis.

ECOG Score: 0–1.

Adequate function of major organs, including normal baseline blood routine, hepatic and renal function, as well as cardiac and pulmonary function.

HER2 was negative.

At least one measurable lesion (based on RECIST V.1.1 criteria).

Expected survival time ≥3 months.

Progression on or were intolerant to first-line immunochemotherapy:

• Patients were also eligible if they progressed during initial chemotherapy, or if patients with postoperative recurrence or metastasis progressed during concurrent chemoradiotherapy.

• For neoadjuvant/adjuvant immunotherapy, if patients progress during the treatment or within 6 months after treatment, it is considered as a failure of first-line treatment.

• Patients with an adverse immune reaction resulting in discontinuation of the prior anti-PD-1/PD-L1 immunotherapy are also eligible. (Patients must not have experienced any of the following: any grade 3 or more severe immune-related adverse event (irAE); any unresolved grade 2 irAE; or any toxicity condition that resulted in permanent discontinuation of prior anti-PD-1/PD-L1 immunotherapy.)

Women of childbearing age should consent to take contraception measures during the study period and within 6 months after the study ends. Female subjects must have a negative serum or urine pregnancy test within 7 days before the recruitment. Female subjects must be non-lactating women. Men should consent to contraception during the study period and for 6 months after the end of the study.

Have any active autoimmune disease or a history of autoimmune disease (including but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, pituitaritis, vasculitis, nephritis, hyperthyroidism, etc).

Currently receiving immunosuppressors or systemic hormone therapy for immunosuppressor purposes (dose≥10 mg/day, prednisone or other equivalent hormone) and continued use within 2 weeks before recruitment.

Patients received treatment with VEGFR inhibitors, such as sorafenib, sunitinib, apatinib, etc.

Any of the following conditions that will interfere with oral medications: unable to swallow, having received gastroenterostomy, chronic diarrhoea and intestinal obstruction.

Patients with any serious and/or uncontrollable medical condition, including:

• Poor blood pressure control (systolic pressure≥150 mm Hg or diastolic pressure≥100 mm Hg).

• Having myocardial ischaemia or myocardial infarction and arrhythmia of grade 1 and above (including QT interval≥480 ms) and cardiac insufficiency of grade 1.

• Active or uncontrolled severe infection; liver diseases, such as decompensated liver failure, active hepatitis B (HBV-DNA≥10⁴ copy number/mL or 2000 IU/mL) or hepatitis C (positive anti-HCV antibody, HCV-RNA above the lower limit of detection by assay).

• Urine routine examination indicated urinary protein ≥ ++ and confirmed 24-hour urinary protein quantification>1.0 g.

Wounds or fractures that have not healed for a long time.

Has a tendency to bleed (eg, active peptic ulcer) or is currently receiving thrombolytic or anticoagulant therapy such as warfarin, heparin or its analogues.

Patients who have had an arterial/venous thrombotic event within 6 months, such as cerebrovascular accident (including transient ischaemic attack), deep vein thrombosis and pulmonary embolism.

The probability of tumour invasion of important blood vessels is high based on radiological examination, which may lead to fatal bleeding during future study.

Pregnant or breastfeeding.

Patients with a history of other malignant tumours in the past 5 years (except cured basal cell carcinoma and cervical carcinoma in situ).

Patients with a history of psychotropic drug abuse and addiction or mental disorders.

Patients who have participated in clinical trials of other drugs in the past 4 weeks.

A concomitant disease determined by the investigator to seriously compromise the patient’s safety or prevent the patient from completing the study; other patients deemed unsuitable for participation.

Other patients who are considered inappropriate for participation by the investigator.