Study on Adding 2141-V11 to Standard Treatment for Advanced Esophageal, Gastric, or Gastroesophageal Junction Cancer

Inclusion Criteria

• Diagnosed with esophageal, gastric, or gastroesophageal junction adenocarcinoma.
• Cancer is advanced and cannot be removed by surgery or has spread to other parts of the body.
• Currently receiving first-line treatment with a combination of fluoropyrimidine and anti-PD-1 therapy for advanced cancer for at least 3 months but not more than 9 months.
  • Platinum-based chemotherapy in the initial treatment has been stopped or will be stopped at least 2 weeks before starting 2141-V11.
  • Patients in the initial safety group must be on 5-FU.
• The main tumor is still present and visible during an endoscopy at the time of joining the study (within 1 month of starting 2141-V11).
• Cancer can be measured according to specific criteria at the start of 2141-V11 treatment.
• Able to undergo an endoscopy procedure.
• Aged 18 years or older.
• In good general health with a performance status score of 0 or 1.
• Have adequate organ function as shown by specific blood test results:
  • Neutrophil count of at least 1000/mcL.
  • Platelet count of at least 90,000/mcL.
  • Hemoglobin level of at least 8 g/dL.
  • Serum creatinine level no more than 1.5 times the upper limit of normal.
  • Total bilirubin level no more than 1.5 times the upper limit of normal, or direct bilirubin within normal limits if total bilirubin is higher, except for patients with Gilbert's disease (up to 3 times the upper limit).
  • AST and ALT levels no more than 3 times the upper limit of normal.
  • Albumin level of at least 3 mg/dL.

Exclusion Criteria

• Cancer with specific genetic features (dMMR or MSI-H) or known HER2-positive status.
• Previous radiation therapy to the main tumor.
• Anti-PD-1 therapy in the current treatment plan has been stopped for any reason.
• Cancer has worsened on the current treatment.
• Active autoimmune disease requiring ongoing steroid or immunosuppressive treatment within 7 days before starting the study.
• Currently taking systemic steroids or immunosuppressive therapy exceeding a certain dose within 7 days before starting the study, except for specific short-term uses.
• Active infection requiring intravenous antibiotics.
• History of severe immune-related side effects from anti-PD-1 therapy, unless approved by the study lead.
• Previous treatment with PD-1, PD-L1, or CTLA-4 inhibitors before the current treatment.
• Participating in another treatment study or having done so within 4 weeks before starting this study.
• Active cancer spread to the brain or spinal cord.
• HIV, HBV, and HCV testing is not required, but patients with these infections must meet specific criteria:
  • HIV-positive patients must be on effective treatment with undetectable viral load.
  • HBV infection must be controlled with undetectable viral load if on treatment.
  • HCV infection must be treated and cured, or if on treatment, must have undetectable viral load.
• Unwilling or unable to give informed consent or comply with study requirements.