SBRT in Combination With Sintilimab and GM-CSF for the Treatment of Advanced NSCLC

Inclusion Criteria:

* Age at least 18 years.
* ECOG PS 0-1.
* Pathologically confirmed stage IV NSCLC.
* Negative for driver genes including EGFR，ALK，and ROS-1.
* Patients with disease progression after first-line platinum-based therapy without anti-PD-1 or PD-L1 treatment.
* Patients with at least one lesion (size 1-5cm) eligible for SBRT (24Gy/3Fx) and simultaneously at least one measurable lesion (in addition to the lesion treated with SBRT) as defined by RECIST1.1.
* Patients with brain metastasis are eligible if they are asymptomatic, neurologically stable, and off corticosteroids.
* Life expectancy of more than 3 months.
* Patients with no indications for palliative radiotherapy in the opinion of the investigator.
* Patients with a prior history of surgery are eligible if they have recovered adequately from the toxicity and/or complications of surgery.
* Signed informed consent for the use of fresh tumor biopsies before and during the treatment.
* Women of childbearing age and men must agree to use effective contraception during the trial.
* Adequate organ function within 1 week prior to the enrollment：

  1. Adequate bone marrow function: hemoglobin ≥80g/L, white blood cell (WBC) count ≥ 4.0 \* 10 \^ 9/L or neutrophil count ≥ 1.5 \* 10 \^ 9/L, and platelet count ≥ 100 \* 10 \^ 9/L;
  2. Adequate hepatic function: total bilirubin \< 1.5 x upper limit of normal (ULN). Note: If total bilirubin is \> 1.5 x ULN, direct bilirubin must ≤ ULN, Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) ≤2.5 ULN;
  3. Adequate renal function: serum creatinine ≤ 1.5 x ULN or creatinine clearance ≥ 50 mL/min;
* Ability to understand and willingness to provide the informed consent.

Exclusion Criteria:

* Prior exposure to immunomodulatory agent,including but limited to anti-PD-1 or anti-PD-L1 antibodies.
* Severe autoimmune disease: inflammatory bowel disease (including Crohn's disease and ulcerative colitis) 、rheumatoid arthritis、scleroderma、systemic lupus erythematosus 、Wegener's granulomatosis and related vasculitides.
* Patients receiving non-platinum-based chemotherapy as first-line treatment
* Mixed small cell with non-small cell lung cancer histology.
* Pregnant or lactating women.
* Symptomatic interstitial lung disease or active infectious/non-infectious pneumonitis.
* History of any other malignancy.
* Patients in whom palliative radiotherapy is indicated in the opinion of the investigator.
* Active infection, congestive heart failure, myocardial infarction within the 6 months prior to enrollment, unstable angina pectoris or cardiac arrhythmia.
* Prior allergic reaction or contraindications to sintilimab and GM-CSF.
* Patients who have received tumor vaccine; or administration of live, attenuated vaccine within 4 weeks before the start of treatment. Note: Influenza vaccination is permitted only during influenza season, while live, attenuated influenza vaccine such as FluMist is not allowed.
* Patients receiving concurrent chemotherapy drugs,other immunosuppressive agents,or other investigational treatment.Long-term corticosteroid users are also excluded.
* Mental disorders, drug abuse, and social condition that may negatively impact compliance in the opinion of the investigator.