Pembrolizumab/Vibostolimab (MK-7684A) or Atezolizumab in Combination With Chemotherapy in First Line Treatment of Extensive-Stage Small Cell Lung Cancer (MK-7684A-008/KEYVIBE-008)

Overall Survival (OS) was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the final analysis were censored at the date of the last follow-up. OS was calculated using the nonparametric Kaplan-Meier method for censored data.

PFS was defined as the time from randomization to the first documented progressive disease (PD) or death due to any cause, whichever occurred first. Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1), PD was defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also have demonstrated an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. Per protocol, RECIST 1.1 was modified to allow up to 10 target lesions total (up to 5 per organ). PFS was calculated using the nonparametric Kaplan-Meier method; participants who did not experience a PFS event were censored at the last disease assessment, or the last assessment before new anticancer treatment if new treatment was initiated. PFS as assessed by blinded independent central review (BICR) per RECIST 1.1 is presented.

ORR was defined as the percentage of participants in the analysis population who have a confirmed Complete Response (CR: disappearance of all lesions) or a Partial Response (PR: ≥30% decrease in the sum of target lesion diameters without progression in other lesions) per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by Blinded Independent Central Review (BICR). Per protocol, RECIST 1.1 was modified to allow up to 10 target lesions total (up to 5 per organ). The ORR was calculated using the Miettinen & Nurminen method stratified by baseline ECOG performance status (0 or 1), baseline LDH (≤ or > upper limit of normal [ULN]), and baseline presence of liver metastasis (Yes or No), or brain metastasis (Yes or No).

For participants who demonstrated a confirmed Complete Response (CR: disappearance of all lesions) or Partial Response (PR: ≥30% decrease in the sum of target lesion diameters without progression in other lesions) per RECIST 1.1, DOR was defined as the time from first documented CR or PR until progressive disease (PD) or death from any cause, whichever occurs first. Per protocol, RECIST 1.1 was modified to allow up to 10 target lesions total (up to 5 per organ). DOR was calculated using the nonparametric Kaplan-Meier method for censored data.

An AE is 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.

An AE is 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.

The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the quality of life (QoL) of individuals with cancer. 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 QoL during the past week?") are scored on a 7-point scale (1=Very Poor to 7=Excellent). A higher score indicates a better overall outcome.

The EORTC QLQ-C30 is a cancer specific health-related QoL questionnaire. Participant responses to 5 questions about their physical functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Higher scores indicate a worse level of function.

The EORTC QLQ-C30 is a cancer specific health-related QoL questionnaire. Participant response to the question "Were you short of breath?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score indicates a worse level of dyspnea.

The EORTC QLQ-LC13 is a lung cancer specific health-related QoL questionnaire. Participant response to the question "Have you coughed?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score indicates more frequent coughing.

EORTC QLQ-LC13 is a lung cancer specific health-related QoL questionnaire. Participant response to the question "Have you had pain in your chest?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score indicates a worse level of chest pain.

The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the QoL of individuals with cancer. 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 QoL during the past week?") are scored on a 7-point scale (1=Very Poor to 7=Excellent). A higher score indicates 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.

The EORTC QLQ-C30 is a cancer specific health-related QoL questionnaire. Participant responses to 5 questions about their physical functioning are scored on a 4-point scale (1=Not at All to 4=Very Much). Higher scores indicate a worse level of function. 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.

The EORTC QLQ-C30 is a cancer specific health-related QoL questionnaire. Participant response to the question "Were you short of breath?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score 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.

The EORTC QLQ-LC13 is a lung cancer specific health-related QoL questionnaire. Participant response to the question "Have you coughed?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score indicates more frequent coughing. 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.

The EORTC QLQ-LC13 is a lung cancer specific health-related QoL questionnaire. Participant response to the question "Have you had pain in your chest?" is scored on a 4-point scale (1=Not at All to 4=Very Much). A higher score indicates a 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.