Study of Pembrolizumab (MK-3475) Monotherapy Versus Sacituzumab Govitecan in Combination With Pembrolizumab for Participants With Metastatic Non-small Cell Lung Cancer (NSCLC) With Programmed Cell Death Ligand 1 (PD-L1) Tumor Proportion Score (TPS) ≥50% (MK-3475-D46)

PFS is defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurs first as per the Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1). PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. RECIST 1.1 is modified to follow a maximum of 10 target lesions and a maximum of 5 target lesions per organ. PFS as assessed by blinded independent central review (BICR) will be presented.

OS is defined as the time from randomization to death due to any cause.

OR is defined as the confirmed Complete Response (CR: Disappearance of all target lesions) or a Partial Response (PR: At least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1 by BICR.

DOR is defined as the time from the first documented evidence of a Complete Response (CR: Disappearance of all target lesions) or a Partial Response (PR: At least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1 until Progressive Disease (PD) or death due to any cause, whichever occurs first, in participants demonstrating a CR or PR. Per RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered PD.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the questions "How would you rate your overall health during the past week?" and "How would you rate your overall quality of life during the past week?" will be scored on a 7-point scale (1= Very poor to 7=Excellent). Using linear transformation, raw scores will be standardized, so that scores range from 0 to 100. Higher scores indicate a better overall health status. Per protocol, the change from baseline in EORTC QLQ-C30 Items 29 and 30 combined score will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to 5 questions about their physical functioning will be scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores will be standardized, so that scores range from 0 to 100. Higher scores indicate a better level of physical functioning. The change from baseline in Physical Functioning (EORTC QLQ-C30 Items 1-5) combined score will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the questions "Were you limited in doing either your work or other daily activities during the past week?" and " Were you limited in pursuing your hobbies or other leisure time activities during the past week?" will be scored on a 4-point scale (1=Not at All to 4=Very Much). Higher scores indicate a better level of role functioning. Change from baseline in the role functioning (EORTC QLQ-C30 Items 6-7) combined score will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "Were you short of breath?" will be scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores will be standardized, so that scores range from 0 to 100. Higher scores indicates a worse level of dyspnea. The change from baseline in dyspnea (EORTC QLQ-C30 Item 8) score will be presented.

The EORTC QLQ-LC13 is a lung cancer-specific supplemental questionnaire used in combination with the EORTC QLQ-C30. Participant responses to the question "How much did you cough?" will be 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. Higher scores indicate more frequent coughing and a worse outcome. The change from baseline in cough (EORTC QLQ-LC13 Item 31) score will be presented.

The EORTC QLQ-LC13 is a lung cancer-specific supplemental questionnaire used in combination with the EORTC QLQ-C30. Participant responses to the question "Have you had pain in your chest?" 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. Higher scores indicate worse level of chest pain. The change from baseline in chest pain (EORTC QLQ-LC13 Item 40) score will be presented.

The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the quality of life of cancer patients. Participant responses to Items 29 and 30 ("How would you rate your overall health during the past week?" and "How would you rate your overall quality of life during the past week?") will be scored on a 7-point scale (1=Very Poor to 7=Excellent). Higher scores indicate a better overall outcome. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-C30 Items 29 and 30 will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to 5 questions about their physical functioning will be scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores will be standardized, so that scores range from 0 to 100. Higher scores indicate a better level of physical functioning. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-C30 Items 1-5 will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the questions "Were you limited in doing either your work or other daily activities during the past week?" and " Were you limited in pursuing your hobbies or other leisure time activities during the past week?" will be scored on a 4-point scale (1=Not at All to 4=Very Much). Higher scores indicate a better level of role functioning. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-C30 Items 6-7 will be presented.

The EORTC QLQ-C30 is a 30-item questionnaire to assess the overall quality of life of cancer patients. Participant responses to the question "Were you short of breath?" will be scored on a 4-point scale (1=Not at All to 4=Very Much). Using linear transformation, raw scores will be standardized, so that scores range from 0 to 100. Higher scores indicates a worse level of dyspnea. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-C30 Item 8 will be presented.

The EORTC QLQ-LC13 is a lung cancer-specific supplemental questionnaire used in combination with the EORTC QLQ-C30. Participant responses to the question "How much did you cough?" will be 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. Higher scores indicate more frequent coughing and a worse outcome. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-LC13 Item 31 will be presented.

The EORTC QLQ-LC13 is a lung cancer-specific supplemental questionnaire used in combination with the EORTC QLQ-C30. Participant responses to the question "Have you had pain in your chest?" 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. Higher scores indicate worse level of chest pain. TTD is defined as the time to first onset of 10 or more (out of 100) deterioration from baseline and confirmed by a second adjacent 10 or more deterioration from baseline. TTD in the score of EORTC QLQ-LC13 Item 40 will be presented.

An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a study intervention. Per protocol, the number of participants who experience an AE will be reported.

An AE is any untoward medical occurrence in a participant, temporally associated with the use of study treatment, whether or not considered related to the study treatment. An AE can therefore be any unfavourable and unintended sign (including an abnormal laboratory finding, for example), symptom, or disease temporally associated with the use of a study intervention. Per protocol, the number of participants who discontinue study treatment due to an AE will be reported.