The purpose of this study is to evaluate the efficacy and safety of Camrelizumab or Camrelizumab plus chemotherapy in patients with untreated, advanced ESCC with PD-L1 CPS≥10 ,who have been achieved PR and CR after treated with Camrelizumab.

Standard 1L chemotherapy for advanced or metastatic esophageal squamous cell cancer(ESCC) results in poor OS(median<1year).Camrelizumab provided superior OS versus chemotherapy in heavily pretreated advanced/rucurrent ESCC.PD-1 antibody +chemo showed promisng antitumor activity in 1L advanced or metastatic ESCC.PD-L1 expression by CPS at cutoff≥10 has shown better enrichment for efficacy fo checkpoint inhibitors in ESCC.Recently, two clinical trials on Pembrolizumb have attracted our attention,KEYNOTE-181 and KEYNOTE-590.The median duration of response was 9.3 months in pembrolizumab monotherapy (KEYNOTE-181) ,and 8.3 months in Pembrolizumb plus chemotherapy (KEYNOTE-590). We hypothesis that administration of the PD-1 inhibitor will significantly prolong survival compared to PD-1 inhibitor combined with chemotherapy, when used as maintenance therapy in patients sensitive to PD-1 inhibitors.

Inclusion Criteria:

• • Male or female

  • Age ≥18 years
  • Histologically or cytologically confirmed locally advanced unresectable or metastatic ESCC
  • Measurable disease per RECIST v1.1 assessed by the local investigator
  • ECOG performance status 0 or 1
  • Provide newly obtained (preferred) or archival tissue sample
  • Negative urine or serum pregnancy test within 72 h before randomization (females)
  • Willing to use an adequate method of contraception throughout the study and for 120 days after the last dose of study medication and up to 180 days after the last dose of cisplatin
  • Adequate hematologic function, defined as ANC ≥ 1500/μl,platelet count ≥ 100,000/μl and hemoglobin ≥ 9.0 g/dl or ≥5.6 mmol/l
  • Adequate renal function, defined as creatinine ≤ 1.5 × ULN or measured or calculated creatinine clearance ≥ 60 mL/min for those with creatinine levels 1.5 × ULN
  • Adequate hepatic function, defined as total bilirubin ≤1.5 × ULN, or direct bilirubin ≤ ULN for those with total bilirubin levels 1.5 × ULN, and ALT/AST levels ≤ 2.5 × ULN
  • Adequate coagulation function, defined as INR ≤ 1.5 × ULN unless the patient is receiving anticoagulant therapy as long as PT or aPTT is within the therapeutic range
  • Written informed consent

Exclusion Criteria:

• • Locally advanced esophageal carcinoma that is resectable or potentially curable with radiation therapy per local investigator

  • Previous therapy for advanced disease
  • Major surgery, open biopsy or significant traumatic injury within 28 days before randomization or anticipated need for major surgery during the study treatment period
  • Known additional malignancy that is progressing or requires active treatment (except for BCC or SCC of the skin, in situ cervical cancer, in situ breast cancer that has undergone potentially curative treatment and in situ or intramucosal pharyngeal cancer)
  • Known active CNS metastases and/or carcinomatous meningitis; patients with previously treated and radiologically stable brain metastases may be eligible
  • Active autoimmune disease that has necessitated systemic treatment (other than replacement therapy) in the past 2 years
  • Diagnosis of immunodeficiency, receiving chronic systemic steroid therapy 10 mg daily prednisone equivalent or any other form of immunosuppressive therapy within 7 days before the first dose of study treatment or history of organ transplant including allogeneic stem cell transplant
  • Active infection necessitating systemic therapy
  • History or current evidence of any condition, therapy or laboratory abnormality that might confound the study results or interfere with study participation