• Progression-free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) [ Time Frame: Up to approximately 3 years ]
  Progression-free Survival is the time from the date of randomization until either documented disease progression or death due to any cause, whichever occurs first.
• Overall Survival (OS) [ Time Frame: Up to approximately 5 years ]
  Overall survival is the time from the date of randomization to death due to any cause.

• Number of Participants With One or More Adverse Events (AEs) [ Time Frame: Up to approximately 5 years ]
  An adverse event (AE) is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study.
• Number of participants discontinuing study intervention due to adverse events (AEs) [ Time Frame: Up to approximately 5 years ]
  An AE is defined as any unfavorable and unintended sign including an abnormal laboratory finding, symptom or disease associated with the use of a medical treatment or procedure, regardless of whether it is considered related to the medical treatment or procedure, that occurs during the course of the study.
• Change from Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Global Health Status / Quality of Life (Items 29 and 30) Scale Score [ Time Frame: Baseline (at randomization) and Week 18 post-randomization ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "How would you rate your overall health during the past week?" are scored on a 7-point scale (1= Very poor to 7=Excellent). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better overall health status. The change from baseline in EORTC QLQ-C30 Items 29 and 30 scores will be presented.
• Change from Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Lung Cancer Module 13 (QLQ-LC13) Cough (Item 1) Scale Score [ Time Frame: Baseline (at randomization) and Week 18 post-randomization ]
  The EORTC QLQ-LC13 is a lung cancer specific supplemental questionnaire used in combination with the EORTC QLQ-C30 questionnaire. Participant responses to the question "How much did you cough?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better outcome. The change from baseline in EORTC QLQ-LC13 cough (Item 1) score will be presented.
• Change from Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Lung Cancer Module 13 (QLQ-LC13) Chest Pain (Item 10) Scale Score [ Time Frame: Baseline (at randomization) and Week 18 post-randomization ]
  The EORTC QLQ-LC13 is a lung cancer specific supplemental questionnaire used in combination with the EORTC QLQ-C30 questionnaire. Participant responses to the question "How was your chest pain?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better outcome. The change from baseline in EORTC QLQ-LC13 chest pain (Item 10) score will be presented.
• Change from Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Dyspnea (Item 8) Scale Score [ Time Frame: Baseline (at randomization) and Week 18 post-randomization ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "Were you short of breath?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. The change from baseline in EORTC QLQ-LC13 dyspnea (Item 8) score will be presented. A lower score indicates a better outcome.
• Change from Baseline in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Physical Functioning (Items 1 to 5) Scale Score [ Time Frame: Baseline (at randomization) and Week 18 post-randomization ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to 5 questions about their physical functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better quality of life. The change from baseline in Physical Functioning (EORTC QLQ-C30 Items 1-5) score will be presented.
• Time to True Deterioration (TTD) in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Global Health Status / Quality of Life (Items 29 and 30) Scale Score [ Time Frame: Up to approximately 5 years ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "How would you rate your overall health during the past week?" are scored on a 7-point scale (1= Very poor to 7=Excellent). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better overall health status. TTD was defined as the time from baseline (at randomization) to the first onset of a ≥10-point decrease with confirmation by the subsequent visit of a ≥10-point decrease in Items 29 and 30 scale scores.
• Time to True Deterioration (TTD) in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Lung Cancer Module 13 (QLQ-LC13) Cough (Item 1) Scale Score [ Time Frame: Up to approximately 5 years ]
  The EORTC QLQ-LC13 is a lung cancer specific supplemental questionnaire used in combination with the EORTC QLQ-C30 questionnaire. Participant responses to the question "How much did you cough?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better outcome. TTD was defined as the time from baseline (at randomization) to the first onset of a ≥10-point decrease with confirmation by the subsequent visit of a ≥10-point decrease in cough scale score.
• Time to True Deterioration (TTD) in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire Lung Cancer Module 13 (QLQ-LC13) Chest Pain (Item 10) Scale Score [ Time Frame: Up to approximately 5 years ]
  The EORTC QLQ-LC13 is a lung cancer specific supplemental questionnaire used in combination with the EORTC QLQ-C30 questionnaire. Participant responses to the question "How was your chest pain?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better outcome. TTD was defined as the time from baseline (at randomization) to the first onset of a ≥10-point decrease with confirmation by the subsequent visit of a ≥10-point decrease in chest pain scale score.
• Time to True Deterioration (TTD) in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Dyspnea (Item 8) Scale Score [ Time Frame: Up to approximately 5 years ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "Were you short of breath?" are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A lower score indicates a better outcome. TTD was defined as the time from baseline (at randomization) to the first onset of a ≥10-point decrease with confirmation by the subsequent visit of a ≥10-point decrease in Item 8 scale score.
• Time to True Deterioration (TTD) in European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30) Physical Functioning (Items 1 to 5) Scale Score [ Time Frame: Up to approximately 5 years ]
  The EORTC QLQ-C30 is a questionnaire to assess the overall quality of life of cancer patients. Participant responses to 5 questions about their physical functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores are standardized, so that scores range from 0 to 100. A higher score indicates a better quality of life. TTD was defined as the time from baseline (at randomization) to the first onset of a ≥10-point decrease with confirmation by the subsequent visit of a ≥10-point decrease in physical functioning Items 1 to 5 scale scores.

The current study will compare pembrolizumab (MK-3475) plus maintenance olaparib, vs. pembrolizumab plus maintenance olaparib placebo for the treatment of squamous NSCLC. The study's 2 primary hypotheses are:

1. Pembrolizumab plus maintenance olaparib is superior to pembrolizumab plus maintenance olaparib placebo with respect to progression-free survival (PFS) per RECIST 1.1 by blinded independent clinical review (BICR).
2. Pembrolizumab plus maintenance olaparib is superior to pembrolizumab plus maintenance olaparib placebo with respect to overall survival (OS).

• Biological: Pembrolizumab
  IV infusion
  Other Name: MK-3475
• Drug: Carboplatin
  IV infusion
  Other Name: PARAPLATIN®
• Drug: Paclitaxel
  IV infusion
  Other Names:

  • TAXOL®
  • ONXAL™
• Drug: Nab-paclitaxel
  IV infusion
  Other Name: ABRAXANE®
• Drug: Olaparib
  Tablets
  Other Name: LYNPARZA®
• Drug: Placebo
  Placebo to olaparib, tablets

• Experimental: Pembrolizumab + Carboplatin + Taxane + Olaparib

  For the Induction Phase, participants receive 4 cycles:

  Pembrolizumab 200 mg, intravenous (IV) on Day 1 of each 21-day cycle PLUS carboplatin PLUS a taxane (either paclitaxel or nab-paclitaxel) for 4 cycles (21-day cycles). If the participant has a complete or partial response or stable disease to induction therapy, the participant is randomized to maintenance therapy.

  For the Maintenance Phase, participants receive pembrolizumab IV on Day 1 of each 21-day for up to 31 cycles PLUS maintenance oral olaparib 300 mg twice daily. In the Maintenance Phase, the participant continues to receive maintenance olaparib until centrally verified progressive disease, physician decision or intolerable toxicity.

  Interventions:

  • Biological: Pembrolizumab
  • Drug: Carboplatin
  • Drug: Paclitaxel
  • Drug: Nab-paclitaxel
  • Drug: Olaparib
• Active Comparator: Pembrolizumab + Carboplatin + Taxane + Olaparib Placebo

  For the Induction Phase, participants receive 4 cycles:

  Pembrolizumab 200 mg, intravenous (IV) on Day 1 of each 21-day cycle PLUS carboplatin PLUS a taxane (either paclitaxel or nab-paclitaxel) for 4 cycles (21-day cycles). If the participant has a complete or partial response or stable disease to induction therapy, the participant is randomized to maintenance therapy.

  For the Maintenance Phase, participants receive pembrolizumab IV on Day 1 of each 21-day for up to 31 cycles PLUS matching maintenance olaparib placebo twice daily. In the Maintenance Phase, the participant continues to receive maintenance olaparib placebo until centrally verified progressive disease, physician decision or intolerable toxicity.

  Interventions:

  • Biological: Pembrolizumab
  • Drug: Carboplatin
  • Drug: Paclitaxel
  • Drug: Nab-paclitaxel
  • Drug: Placebo

Inclusion Criteria:

1. Have a histologically or cytologically confirmed diagnosis squamous NSCLC.
2. Have Stage IV squamous NSCLC.
3. Have measurable disease based on RECIST 1.1.
4. Have not received prior systemic treatment for their advanced/metastatic NSCLC.

5. Have provided archival tumor tissue sample or newly obtained core or incisional biopsy of a tumor lesion not previously irradiated.

   Note: Adequacy of biopsy specimen for the above analyses must be confirmed by the central laboratory before the participant can receive study intervention(s). Submission of another tumor specimen may be required prior to enrolling the participant, if adequate tumor tissue was not provided the first time.

6. Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Status assessed within 7 days prior to the administration of study intervention
7. Have a life expectancy of at least 3 months.
8. Has adequate organ function.
9. Male and female participants who are not pregnant and of childbearing potential must follow contraceptive guidance during the treatment period and for 180 days afterwards.
10. Male participants must refrain from donating sperm during the treatment period and for 180 days afterwards.

Exclusion Criteria:

1. Has non-squamous histology NSCLC.
2. Has a known additional malignancy that is progressing or has progressed within the past 3 years requiring active treatment.
3. Has known active central nervous system metastases and/or carcinomatous meningitis.
4. Has a known hypersensitivity to any components or excipients of carboplatin, paclitaxel or nab-paclitaxel, or olaparib.
5. Has a severe hypersensitivity (≥Grade 3) to pembrolizumab and/or any of its excipients.
6. Has an active autoimmune disease that has required systemic treatment in past 2 years.
7. Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy.
8. Has a known history of human immunodeficiency virus (HIV) infection, a known history of hepatitis B infection, or known active hepatitis C virus infection.
9. Has interstitial lung disease, or history of pneumonitis requiring systemic steroids for treatment.
10. Has received prior therapy with olaparib or with any other polyadenosine 5' diphosphoribose (polyADP ribose) polymerization (PARP) inhibitor.
11. Has received prior therapy with an agent directed to programmed cell death ligand 1 (PD-L1), anti PD-L2, or directed to a stimulatory or co-inhibitory T-cell receptor (e.g., cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), OX-40, CD137).
12. Has myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) or with features suggestive of MDS/AML.