Retlirafusp Alfa Combined With Apatinib and Nab-Paclitaxel as Second-line Treatment for Gastric or Gastroesophageal Junction Cancer

Prior treatment

• Prior treatment with any VEGFR inhibitor (including apatinib, sorafenib, sunitinib)
• Prior treatment with retlirafusp alf
• Received any investigational drug within 4 weeks before first dose
• Received systemic corticosteroid (\> 10 mg prednisone equivalent daily) or other immunosuppressive agents within 2 weeks before first dose, except for allowed topical/inhaled use or physiological replacement
• Severe infection (CTCAE Grade \> 2) within 4 weeks before first dose; active pulmonary infection, interstitial lung disease, non-infectious pneumonitis, pulmonary fibrosis; active tuberculosis

Other illness

• Known hypersensitivity to any component of the study drugs
• Active autoimmune disease or history of autoimmune disease (except controlled hypothyroidism, type 1 diabetes with stable insulin, vitiligo, resolved childhood asthma)
• Known immunodeficiency (including HIV infection), organ transplantation, or allogeneic hematopoietic stem cell transplantation
• Uncontrolled cardiac disease: NYHA Class ≥ II heart failure, unstable angina, myocardial infarction within 1 year, clinically significant arrhythmia requiring intervention
• Active hepatitis B (HBV DNA ≥ 2000 IU/mL) or active hepatitis C (HCV RNA positive)
• History of other malignancy within 5 years before enrollment, except adequately treated basal cell carcinoma, squamous cell carcinoma of skin, or carcinoma in situ of cervix
• Any other condition deemed inappropriate by the investigator

Other

• Pregnant or lactating women
• Unwilling or unable to comply with study procedures

• Able to provide written informed consent prior to any study-specific procedures
• Age ≥ 18 years
• ECOG performance status 0 or 1
• Histologically or cytologically confirmed gastric adenocarcinoma or gastroesophageal junction adenocarcinoma, locally advanced unresectable, locally recurrent, or metastatic
• Human epidermal growth factor receptor 2 (HER2) negative
• Failed first-line immunotherapy-containing systemic treatment
• At least one measurable lesion per RECIST Version 1.1
• Adequate organ function:
  • 1)Hemoglobin ≥ 90 g/L 2)Absolute neutrophil count ≥ 1.5 × 10⁹/L 3)Platelet count ≥ 80 × 10⁹/L 4)Total bilirubin \< 1.5 × upper limit of normal (ULN) 5)ALT/AST \< 2.5 × ULN; \< 5 × ULN in patients with liver metastasis 6)Serum creatinine ≤ 1.5 × ULN or creatinine clearance \> 60 mL/min 7)Urine protein \< 2+ or 24-hour urine protein \< 1 g 8)Left ventricular ejection fraction (LVEF) ≥ 50% 9)Coagulation function: INR ≤ 1.5 × ULN, APTT ≤ 1.5 × ULN 8.Fertile male and female subjects must agree to use highly effective contraception during the study and for 6 months after the last dose of study treatment; female subjects must have a negative pregnancy test within 7 days before enrollment