Inclusion Criteria:
1. Histologically confirmed NSCLC
2. PD-L1 Total Proportion Score (TPS) ≥50%
3. Locally advanced NSCLC (unresectable stage III with indication of curative CRT based on Tumour, Node and Metastasis (TNM) classification of Union for International Cancer Control (UICC) version 8)
4. Treatment naïve for primary disease
5. Have at least measurable disease based on RECIST 1.1.
6. Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1.
7. Have adequate organ function as defined in the following:
Adequate Organ Function and Laboratory Values
Hematological:
Absolute neutrophil count (ANC) ≥1500/μL Platelets ≥100 000/μL Hemoglobin ≥9.0 g/dL or ≥5.6 mmol/L (a)
Renal:
Creatinine OR Measured or calculated (b) creatinine clearance (GFR can also be used in place of creatinine or CrCl) ≤1.5 × Upper Limit of Normal (ULN) OR ≥45 mL/min for participant with creatinine levels \>1.5 × institutional ULN
Hepatic:
Total bilirubin ≤1.5 ×ULN OR direct bilirubin ≤ULN for participants with total bilirubin levels \>1.5 × ULN Aspartate aminotransferase (AST) (SGOT) and Alanine transaminase (ALT) (SGPT) ≤2.5 × ULN
Coagulation:
International normalized ratio (INR) OR prothrombin time (PT) Activated partial thromboplastin time (aPTT) ≤1.5 × ULN unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulants
Thyroid functions:
Thyroid-Stimulating Hormone (TSH) Within institutional ULN (If TSH is not within ULN at baseline, the participant may still be eligible if T3 and free T4 are within ULN.)
1. Criteria must be met without erythropoietin dependency and without packed red blood cell (pRBC) transfusion within last 2 weeks.
2. Creatinine clearance (CrCl) should be calculated per institutional standard.
8. Male/female participants who are at least 20 years of age on the day of signing informed consent
9. Male participants:
A male participant must agree to use a contraception as detailed in of this protocol during the treatment period and for at least 120 days after the last dose of study treatment and refrain from donating sperm during this period.
Female participants:
A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: a.) Not a woman of childbearing potential (WOCBP) as defined in OR b.) A WOCBP who agrees to follow the contraceptive guidance during the treatment period and for at least 120 days after the last dose of study treatment.
10. The participant is discussed in a conference including radiation oncologists.
11. The participant (or legally acceptable representative if applicable) provides written informed consent for the trial.
Exclusion Criteria:
1. A WOCBP who has a positive urine pregnancy test within 72 hours prior to allocation. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required.
2. Has received prior therapy with an anti-PD-1, anti-PD-L1, or anti-PD-L2 agent or with an agent directed to another stimulatory or co-inhibitory T-cell receptor (e.g., Cytotoxic T Lymphocyte-associated Antigen 4 (CTLA-4), OX-40, CD137).
3. Has received any prior systemic anti-cancer therapy. Note: If participant received major surgery, they must have recovered adequately from the toxicity and/or complications from the intervention prior to starting study treatment.
4. Has received a live vaccine within 30 days prior to the first dose of study drug. Examples of live vaccines include, but are not limited to, the following: measles, mumps, rubella, varicella/zoster (chicken pox), yellow fever, rabies, Bacillus Calmette-Guérin (BCG), and typhoid vaccine. Seasonal influenza vaccines for injection are generally killed virus vaccines and are allowed; however, intranasal influenza vaccines (eg, FluMist®) are live attenuated vaccines and are not allowed.
5. Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks prior to the first dose of study treatment.
Note: Participants who have entered the follow-up phase of an investigational study may participate as long as it has been 4 weeks after the last dose of the previous investigational agent.
6. 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.
7. Has a known additional malignancy that is progressing or has required active treatment within the past 5 years. Note: Participants with basal cell carcinoma of the skin, squamous cell carcinoma of the skin, transitional cell carcinoma of urothelial cancer, or carcinoma in situ (e.g. breast carcinoma, cervical cancer in situ) that have undergone potentially curative therapy are not excluded.
8. Has severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.
9. 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). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a form of systemic treatment.
10. Has a history of (non-infectious) pneumonitis that required steroids or has current pneumonitis.
11. Has an active infection requiring systemic therapy.
12. Has a history of tissue/organ transplantation.
13. Has a known history of Human Immunodeficiency Virus (HIV).
14. Has a known history of Hepatitis B (defined as Hepatitis B surface antigen \[HBsAg\] reactive) or known active Hepatitis C virus (HCV) (defined as HCV RNA is detected) infection. Note: no testing for Hepatitis B and Hepatitis C is required unless mandated by local health authority.
15. Has a known history of active Tuberculosis (TB).
16. Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the subject's participation for the full duration of the study, or is not in the best interest of the subject to participate, in the opinion of the treating investigator.
17. Has known psychiatric or substance abuse disorders that would interfere with cooperation with the requirements of the trial.
18. Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the study, starting with the screening visit through 120 days after the last dose of trial treatment.
