The purpose of this study is to observe and evaluate the efficacy and safety of pembrolizumab plus cisplatin and 5-fluorouracil (5-FU) followed Surgery for locally advanced adenocarcinoma of esophagogastric junction

The neoadjuvant chemotherapy/chemoradiotherapy with surgery is the standard treatment in NCCN guideline. But many patients refused or abandon radiotherapy because of the intolerable adverse effects. We designed a single-arm, open-label, phase II trial of pembrolizumab plus cisplatin and 5-fluorouracil (5-FU) followed by radical surgery for locally advanced adenocarcinoma of esophagogastric junction. The purpose of this study is to observe and evaluate the efficacy and safety.

Inclusion Criteria:

1. Histologically confirmed AEG, Siewert type I or II;
2. Potentially resectable cT3-4a, any N, M0 (AJCC 8 TNM classification);
3. Have a performance status of 0 or 1 on the ECOG Performance Scale;
4. Age 18-75 years old, both men and women;
5. Be willing and able to provide written informed consent/assent for the trial;
6. Demonstrate adequate organ function , all screening labs should be performed within 10 days of treatment initiation;
7. Female subject of childbearing potential should have a negative urine or serum pregnancy within 72 hours prior to receiving the first dose of study medication. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required;
8. Be willing to provide tissue from a newly obtained core or excisional biopsy of a tumor lesion through repeated biopsies. Newly-obtained is defined as a specimen obtained up to 4 weeks (28 days) prior to initiation of treatment on Day 1. Subjects for whom newly-obtained samples cannot be provided (e.g. inaccessible or subject safety concern) may submit an archived specimen only upon agreement from the Sponsor.

Exclusion Criteria:

1. Prior therapy (operation, radiotherapy, immunotherapy, or chemotherapy) for AEG;
2. Ineligibility or contraindication for esophagectomy;
3. Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days prior to the first dose of study drug;
4. Has active autoimmune disease that has required systemic treatment in the past 2 years (i.e. with use of disease modifying agents, corticosteroids or immunosuppressive drugs);
5. Has severe hypersensitivity and adverse events (≥Grade 3) to nivolumab and/or any PD-1/PD-L1 inhibitors.