Study of Pembrolizumab (MK-3475) as First-Line Monotherapy and Combination Therapy for Treatment of Advanced Gastric or Gastroesophageal Junction Adenocarcinoma (MK-3475-062/KEYNOTE-062)

Study Overview
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Brief Summary
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This is a study of pembrolizumab (MK-3475) as first-line treatment for participants with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma. Participants whose tumors express programmed death-ligand 1 (PD-L1) will be randomly assigned to one of the three treatment arms of the study: pembrolizumab as monotherapy [pembro mono], pembrolizumab plus standard of care (SOC) chemotherapy with cisplatin plus 5-fluorouracil (5-FU) or capecitabine [pembro combo], or placebo plus SOC chemotherapy with cisplatin plus 5-fluorouracil (5-FU) or capecitabine [SOC]. The primary study hypotheses are that pembrolizumab in combination with SOC chemotherapy is superior to SOC chemotherapy alone in terms of Progression-free Survival (PFS) and Overall Survival (OS) in participants with PD-L1 Combined Positive Score (CPS) ≥1, pembrolizumab in combination with SOC chemotherapy is superior to SOC chemotherapy alone in terms of OS in participants with PD-L1 CPS ≥10, pembrolizumab monotherapy is non-inferior to SOC chemotherapy alone in terms of OS in participants with PD-L1 CPS ≥1, and pembrolizumab monotherapy is superior to SOC chemotherapy alone in terms of OS in participants with PD-L1 CPS ≥1 and in participants with PD-L1 CPS ≥10.

Detailed Description
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As specified by the protocol, primary and secondary efficacy analyses will be evaluated in gastric cancer participants with PD-L1 CPS ≥1 (all participants) and PD-L1 CPS ≥10 (OS) by comparing the pembro mono arm or pembro combo arm separately to the SOC arm.

Official Title
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A Randomized, Active-Controlled, Partially Blinded, Biomarker Select, Phase III Clinical Trial of Pembrolizumab as Monotherapy and in Combination With Cisplatin+5-Fluorouracil Versus Placebo+Cisplatin+5-Fluorouracil as First-Line Treatment in Subjects With Advanced Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma

Conditions
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Gastric Adenocarcinoma

Intervention / Treatment
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* Biological: Pembrolizumab
* Drug: Cisplatin
* Drug: 5-FU
* Drug: Capecitabine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale within 3 days prior to first dose of study medication Has histologically- or cytologically-confirmed diagnosis of locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma Human epidermal growth factor receptor 2- (HER2/neu-) negative and programmed cell death ligand 1 (PD-L1)-positive Has measurable disease Female participants of childbearing potential must be willing to use adequate contraception or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication Male participants of childbearing potential should agree to use an adequate method of contraception starting with the first dose of study medication through 120 days after the last dose of study medication Adequate organ function Exclusion Criteria: Squamous cell or undifferentiated gastric cancer Previous therapy for locally advanced, unresectable or metastatic gastric/GEJ cancer. Participant may have received prior neoadjuvant or adjuvant therapy as long as it was completed at least 6 months prior to randomization Major surgery, open biopsy or significant traumatic injury within 28 days prior to randomization, or anticipation of the need for major surgery during the course of study treatment. Radiotherapy within 14 days of randomization Known additional malignancy that is progressing or requires active treatment with the exception of basal cell carcinoma of the skin, squamous cell carcinoma of the skin that has undergone potentially curative therapy or in situ cervical cancer Known active central nervous system (CNS) metastases and/or carcinomatous meningitis Active autoimmune disease that has required systemic treatment in past 2 years 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 the first dose of study medication History of non-infectious pneumonitis that required steroids or current pneumonitis Active infection requiring systemic therapy Pregnant, breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of study medication Prior therapy with an anti-programmed cell death (PD)-1, anti-PD-L1, or anti-PD-L2 agent Known history of human immunodeficiency virus (HIV) Known active Hepatitis B or C Currently participating in and receiving study therapy 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 medication Received a live vaccine within 30 days prior to the first dose of study medication

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Pembrolizumab Monotherapy (Pembro Mono)<br>Participants will receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 3-week cycle (Q3W). Eligible participants who stop pembrolizumab with Stable Disease (SD) or better but progress after discontinuation may be able to initiate a second course of pembrolizumab for up to 17 cycles (up to approximately 1 additional year) at the investigator's discretion. | Biological: Pembrolizumab<br>* Pembrolizumab 200 mg IV on Day 1 of each week in 3-week cycles for up to 35 cycles (approximately 2 years).<br>* Other names: KEYTRUDA®;|
| Experimental: Pembrolizumab + SOC Chemotherapy (Pembro Combo)<br>Participants will receive pembrolizumab 200 mg Q3W plus cisplatin 80 mg/m^2 Q3W plus 5-FU 800 mg/m^2/day IV infusion on Days 1-5 Q3W. Capecitabine 1000 mg/m^2 twice a day (BID) on Days 1-14 Q3W may be substituted for 5-FU per local guidelines. Eligible participants who stop pembrolizumab with Stable Disease (SD) or better but progress after discontinuation may be able to initiate a second course of pembrolizumab for up to 17 cycles (up to approximately 1 additional year) at the investigator's discretion. | Biological: Pembrolizumab<br>* Pembrolizumab 200 mg IV on Day 1 of each week in 3-week cycles for up to 35 cycles (approximately 2 years).<br>* Other names: KEYTRUDA®;Drug: Cisplatin<br>* Cisplatin 80 mg/m^2 IV on Day 1 of each week in 3-week cycles (6 cycle maximum per local country guidelines).<br>Drug: 5-FU<br>* 5-FU 800 mg/m^2/day IV continuous from Day 1-5 of each 3-week cycle.<br>Drug: Capecitabine<br>* Capecitabine 1000 mg/m^2 twice daily by oral tablet on Day 1-14 of each 3-week cycle.<br>|
| Placebo Comparator: Placebo + SOC Chemotherapy (SOC)<br>Participants receive placebo IV Q3W plus cisplatin 80 mg/m^2 Q3W plus 5-FU 800 mg/m^2/day IV infusion on Days 1-5 Q3W. Capecitabine 1000 mg/m^2 BID on Days 1-14 Q3W may be substituted for 5-FU per local guidelines. | Drug: Cisplatin<br>* Cisplatin 80 mg/m^2 IV on Day 1 of each week in 3-week cycles (6 cycle maximum per local country guidelines).<br>Drug: 5-FU<br>* 5-FU 800 mg/m^2/day IV continuous from Day 1-5 of each 3-week cycle.<br>Drug: Capecitabine<br>* Capecitabine 1000 mg/m^2 twice daily by oral tablet on Day 1-14 of each 3-week cycle.<br>Drug: Placebo<br>* Normal saline IV on Day 1 of each week in 3-week cycles for up to 35 cycles (approximately 2 years).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pembro Combo vs SOC: Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) by Blinded Independent Central Review (BICR) in Participants With PD-L1 CPS ≥1 (All Participants) | PFS was defined as the time from randomization to the first documented progressive disease (PD) per RECIST 1.1 based on BICR, or death due to any cause, whichever occurred first. Per 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 had to demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. Per protocol, PFS in the pembro combo arm was compared to the SOC arm as a pre-specified primary analysis of the Intent-To-Treat (ITT) population. PFS is reported here for all participants in the pembro combo arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, PFS was compared separately between CPS ≥1 participants of the pembro mono arm and SOC arm and is presented later in the record. | Up to approximately 36 months | 
| Pembro Combo vs SOC: Overall Survival (OS) in Participants With PD-L1 CPS ≥1 (All Participants) | 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. Per protocol, OS in the pembro combo arm was compared to the SOC arm as a pre-specified primary analysis of the ITT population. OS is reported here for all participants in the pembro combo arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, OS was compared separately between CPS ≥1 participants of the pembro mono arm and SOC arm and is presented later in the record. | Up to approximately 42 months | 
| Pembro Combo vs SOC: OS in Participants With PD-L1 CPS ≥10 | 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. Per protocol, OS in the pembro combo arm was compared to the SOC arm as a pre-specified primary analysis of the ITT population. OS is reported here for all participants in the pembro combo arm and SOC arm who were PD-L1 CPS ≥10. Per protocol, OS was compared separately between CPS ≥10 participants of the pembro mono arm and SOC arm and is presented later in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: OS in Participants With PD-L1 CPS ≥1 (All Participants) | 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. Per protocol, OS in the pembro mono arm was compared to the SOC arm as a pre-specified primary analysis of the ITT population. OS is reported here for all participants in the pembro mono arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, OS was compared separately between CPS ≥1 participants of the pembro combo arm and SOC arm and is presented earlier in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: OS in Participants With PD-L1 CPS ≥10 | 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. Per protocol, OS in the pembro mono arm was compared to the SOC arm as a pre-specified primary analysis of the ITT population. OS is reported here for all participants in the pembro mono arm and SOC arm who were PD-L1 CPS ≥10. Per protocol, OS was compared separately between CPS ≥10 participants of the pembro combo arm and SOC arm and is presented earlier in the record. | Up to approximately 42 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pembro Combo vs SOC: Objective Response Rate (ORR) Per RECIST 1.1 by BICR in Participants With PD-L1 CPS ≥1 (All Participants) | ORR was defined as the percentage of participants in the analysis population who have a Complete Response (CR: disappearance of all target lesions) or a Partial Response (PR: ≥30% decrease in the sum of diameters of target lesions) per RECIST 1.1. based upon BICR. Per protocol, ORR in the pembro combo arm was compared to the SOC arm as a pre-specified secondary analysis of the ITT population. The percentage of participants who experienced CR or PR is reported here as the ORR for all participants in the pembro combo arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, ORR was compared separately between CPS ≥1 participants of the pembro mono arm and SOC arm and is presented later in the record. | Up to approximately 42 months | 
| Pembro Combo vs SOC: Duration of Response (DOR) Per RECIST 1.1 by BICR in Participants With PD-L1 CPS ≥1 (All Participants) | For participants who demonstrated a confirmed CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1 based upon BICR, DOR was defined as the time from first documented evidence of confirmed CR or PR until PD or death, whichever occurred first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. Per RECIST 1.1, PD was 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 had to demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. DOR is reported here for all participants in the pembro combo arm and SOC arm who were PD-L1 CPS ≥1 (all participants) and had CR or PR. Per protocol, DOR was compared separately between CPS ≥1 responders of the pembro mono arm and SOC arm and is presented later in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: ORR Per RECIST 1.1 by BICR in Participants With PD-L1 CPS ≥1 (All Participants) | ORR was defined as the percentage of participants in the analysis population who have a CR (disappearance of all target lesions) or PR (≥30% decrease in the sum of diameters of target lesions) per RECIST 1.1. based upon BICR. Per protocol, ORR in the pembro mono arm was compared to the SOC arm as a pre-specified secondary analysis of the ITT population. The percentage of participants who experienced CR or PR is reported here as the ORR for all participants in the pembro mono arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, ORR was compared separately between CPS ≥1 participants of the pembro combo arm and SOC arm and is presented earlier in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: DOR Per RECIST 1.1 by BICR in Participants With PD-L1 CPS ≥1 (All Participants) | For participants who demonstrated a confirmed CR (disappearance of all target lesions) or PR (≥30% decrease in the sum of diameters of target lesions) per RECIST 1.1 based upon BICR, DOR was defined as the time from first documented evidence of confirmed CR or PR until PD or death, whichever occurred first. DOR for participants who had not progressed or died at the time of analysis was censored at the date of their last tumor assessment. Per RECIST 1.1, PD was 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 had to demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. DOR is reported here for all participants in the pembro mono arm and SOC arm who were PD-L1 CPS ≥1 (all participants) and had CR or PR. Per protocol, DOR was compared separately between CPS ≥1 responders of the pembro combo arm and SOC arm and is presented earlier in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: PFS Per RECIST 1.1 by BICR in Participants With PD-L1 CPS ≥1 (All Participants) | PFS was defined as the time from randomization to the first documented PD per RECIST 1.1 based on BICR, or death due to any cause, whichever occurred first. Per 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 had to demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions was also considered PD. Per protocol, PFS in the pembro mono arm was compared to the SOC arm as a pre-specified secondary analysis of the ITT population. PFS is reported here for all participants in the pembro mono arm and SOC arm who were PD-L1 CPS ≥1 (all participants). Per protocol, PFS was compared separately between CPS ≥1 participants of the pembro combo arm and SOC arm and is presented earlier in the record. | Up to approximately 42 months | 
| Pembro Mono vs SOC: Change From Baseline to Week 18 in the 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) Combined Score | The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the quality of life of cancer patients. Participant responses to the Global Health Status (GHS) question How would you rate your overall health during the past week? (Item 29) and the Quality of Life (QoL) question How would you rate your overall quality of life during the past week? (Item 30) were scored on a 7-point scale (1=Very Poor to 7=Excellent). Using linear transformation, raw scores were standardized so that scores ranged from 0 to 100, with a higher score indicating a better overall outcome. Per protocol, change from baseline to Week 18 in the GHS/QoL combined score was compared between all participants of the pembro mono arm and the SOC arm as a pre-specified secondary analysis. As specified by the protocol, change from baseline to Week 18 in the GHS/QoL combined score was compared separately between all participants of the pembro combo arm and SOC arm and is presented later in the record. | Baseline, Week 18 | 
| Pembro Combo vs SOC: Change From Baseline to Week 18 in the EORTC QLQ-C30 Global Health Status/Quality of Life (Items 29 and 30) Combined Score | The EORTC-QLQ-C30 is a 30-item questionnaire developed to assess the quality of life of cancer patients. Participant responses to the GHS question How would you rate your overall health during the past week? (Item 29) and the QoL question How would you rate your overall quality of life during the past week? (Item 30) were scored on a 7-point scale (1=Very Poor to 7=Excellent). Using linear transformation, raw scores were standardized so that scores ranged from 0 to 100, with a higher score indicating a better overall outcome. Per protocol, change from baseline to Week 18 in the GHS/QoL combined score was compared between all participants of the pembro combo arm and the SOC arm as a pre-specified secondary analysis. As specified by the protocol, change from baseline to Week 18 in the GHS/QoL combined score was compared separately between all participants of the pembro mono arm and SOC arm and is presented earlier in the record. | Baseline, Week 18 | 
| Pembro Mono vs. SOC: Change From Baseline to Week 18 in EORTC QLQ-Module for Gastric Cancer (STO22) Pain Symptom Subscale Score | EORTC-QLQ-STO22 is a 22-item questionnaire developed to assess QoL of gastric cancer participants. It consists of 5 multi-item subscales that assess dysphagia (3 items), dietary restriction (4 items), pain (4 items), upper gastro-esophageal symptoms (3 items), and emotional problems (3 items), and questions on dry mouth, taste, body image, and hair loss. Participant responses to the Pain symptom subscale (Items 34-37) were scored on a 4-point scale (1=Not at all to 4=Very much). Raw scores were standardized by linear transformation so that scores ranged from 0 to 100, with a higher score indicating more problems. Per protocol, change from baseline to Week 18 in the EORTC-QLQ-STO22 Pain score was compared between the pembro mono arm and the SOC arm as a pre-specified secondary analysis. As specified by the protocol, change from baseline to Week 18 in the EORTC-QLQ-STO22 Pain score was compared separately between the pembro combo arm and SOC arm and is presented later in the record. | Baseline, Week 18 | 
| Pembro Combo vs. SOC: Change From Baseline to Week 18 in EORTC QLQ-STO22 Pain Symptom Subscale Score | EORTC-QLQ-STO22 is a 22-item questionnaire developed to assess QoL of gastric cancer participants. It consists of 5 multi-item subscales that assess dysphagia (3 items), dietary restriction (4 items), pain (4 items), upper gastro-esophageal symptoms (3 items), and emotional problems (3 items), and questions on dry mouth, taste, body image, and hair loss. Participant responses to the Pain symptom subscale (Items 34-37) were scored on a 4-point scale (1=Not at all to 4=Very much). Raw scores were standardized by linear transformation so that scores ranged from 0 to 100, with a higher score indicating more problems. Per protocol, change from baseline to Week 18 in the EORTC-QLQ-STO22 Pain score was compared between the pembro combo arm and the SOC arm as a pre-specified secondary analysis. As specified by the protocol, change from baseline to Week 18 in the EORTC-QLQ-STO22 Pain score was compared separately between the pembro mono arm and SOC arm and is presented earlier in the record. | Baseline, Week 18 | 
| Number of Participants Experiencing an Adverse Event (AE) | An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an adverse event. The number of participants who experienced an AE was reported for each arm according to the treatment received. | Up to approximately 33 months | 
| Number of Participants Discontinuing Study Treatment Due to an AE | An AE was defined as any untoward medical occurrence in a participant administered a pharmaceutical product and which did not necessarily have a causal relationship with this treatment. An AE could therefore be any unfavourable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the medicinal product or protocol-specified procedure. Any worsening of a pre-existing condition that was temporally associated with the use of the Sponsor's product was also an adverse event. The number of participants who discontinued study treatment due to an AE was reported for each arm according to the treatment received. | Up to approximately 30 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric carcinoma, Gastric cancer, Gastroesophageal junction cancer, Gastroesophageal junction carcinoma, Programmed Cell Death-1 (PD1, PD-1),, Programmed Death-Ligand 1 (PDL1, PD-L1), Programmed Cell Death Receptor Ligand 2 (PDL2, PD-L2)