Trial · NCT03675737
Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859)
NCT03675737, Phase 3, Completed, Merck Sharp & Dohme LLC; results first posted 2023-10-12
3 sourcestrials-2026-11-12-0.5.0
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ConductScience Library. Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859). Trials, record NCT03675737. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT03675737
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Trial
As registered on ClinicalTrials.gov, in the graph's capture of the registry.
- Title
- Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859)
- NCT number
- NCT03675737
- Status
- Completed
- Phases
- Phase 3
- Enrollment
- 1,579 participants, actual
- Lead sponsor
- Merck Sharp & Dohme LLC
- Conditions
- Stomach Neoplasms
- Interventions
- Pembrolizumab, Cisplatin, 5-fluorouracil, oxaliplatin, capecitabine, Placebo for Pembrolizumab
- First posted
- 2018-09-18
- Last updated
- 2026-02-27
- Other registries' IDs
- eudract:2018-001757-27
- Results first posted
- 2023-10-12
Source ClinicalTrials.gov
Registered outcomes14
Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.
| List | Outcome | Time frame | Description |
|---|---|---|---|
| Primary | Overall Survival (OS) in All Participants | Up to 45.9 months | OS was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. OS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Primary | Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 45.9 months | OS was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. OS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Primary | Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 45.9 months | OS was defined as the time from randomization to death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. OS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Secondary | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | 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 RECIST 1.1 as assessed by BICR, 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 ≥1 new lesions was also considered PD. PFS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Secondary | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 49.5 months | 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 RECIST 1.1 as assessed by BICR, 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 ≥1 new lesions was also considered PD. PFS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Secondary | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 49.5 months | 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 RECIST 1.1 as assessed by BICR, 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 ≥1 new lesions was also considered PD. PFS was estimated using the product-limit (Kaplan-Meier) method for censored data. |
| Secondary | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | ORR was defined as the percentage of the participants who had a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: ≥30% decrease in the sum of diameters (SOD) of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 as assessed by BICR. |
| Secondary | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 49.5 months | ORR was defined as the percentage of the participants who had a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: ≥30% decrease in the sum of diameters (SOD) of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 as assessed by BICR. |
| Secondary | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 49.5 months | ORR was defined as the percentage of the participants who had a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: ≥30% decrease in the sum of diameters (SOD) of target lesions, taking as reference the baseline SOD) according to RECIST 1.1 as assessed by BICR. |
| Secondary | Duration of Response (DOR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | DOR was defined as the time from first documented evidence of a confirmed Complete Response (CR) or Partial Response (PR) until progressive disease (PD) or death, whichever occurred first. Per RECIST 1.1 as assessed by BICR, CR was the disappearance of all target lesions and PR was ≥30% decrease in the sum of diameters (SOD) of target lesions, taking as reference the baseline SOD. PD was defined as ≥20% increase in the SOD of target lesions according to RECIST 1.1. In addition to the relative increase of 20%, the SOD must also have demonstrated an absolute increase of ≥5 mm. The appearance of ≥1 new lesions was also considered PD. DOR for participants who had not progressed or died at the time of analysis was censored at the date of the last tumor assessment. DOR was estimated using the product-limit (Kaplan-Meier) method for censored data. |
1 to 10 of 14Source ClinicalTrials.gov
See all 14 registered outcomesOutcomes14
Each outcome the trial posted results for, in ClinicalTrials.gov's words.
| Type | Outcome | Time frame | Population | Units | Measured as |
|---|---|---|---|---|---|
| PRIMARY | Overall Survival (OS) in All Participants | Up to 45.9 months | The analysis population included all randomized participants. | Months | MEDIAN |
| PRIMARY | Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 45.9 months | The analysis population included randomized participants with a PD-L1 CPS of ≥1. | Months | MEDIAN |
| PRIMARY | Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 45.9 months | The analysis population included randomized participants with a PD-L1 CPS of ≥10. | Months | MEDIAN |
| SECONDARY | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | The analysis population included all randomized participants. | Months | MEDIAN |
| SECONDARY | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 49.5 months | The analysis population included randomized participants with a PD-L1 CPS ≥1. | Months | MEDIAN |
| SECONDARY | Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 49.5 months | The analysis population included randomized participants with a PD-L1 CPS ≥10. | Months | MEDIAN |
| SECONDARY | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | The analysis population included all randomized participants. | Percentage of Participants | NUMBER |
| SECONDARY | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Up to 49.5 months | The analysis population included randomized participants with a PD-L1 CPS ≥1. | Percentage of Participants | NUMBER |
| SECONDARY | Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Up to 49.5 months | The analysis population included randomized participants with a PD-L1 CPS ≥10. | Percentage of Participants | NUMBER |
| SECONDARY | Duration of Response (DOR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Up to 49.5 months | The analysis population included all randomized participants who experienced a confirmed CR or PR. | Months | MEDIAN |
1 to 10 of 14Source ClinicalTrials.gov
See all 14 outcomesResults by group28
Each measurement the trial posted, group by group, in the words and numbers it posted.
| Outcome | Group | Category | Value | Spread | Units |
|---|---|---|---|---|---|
| Overall Survival (OS) in All Participants | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 12.9 | 95% Confidence Interval 11.9 to 14.0 | Months | |
| Overall Survival (OS) in All Participants | Placebo + Chemotherapy (FP or CAPOX Regimen) | 11.5 | 95% Confidence Interval 10.6 to 12.1 | Months | |
| Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 13.0 | 95% Confidence Interval 11.6 to 14.2 | Months | |
| Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Placebo + Chemotherapy (FP or CAPOX Regimen) | 11.4 | 95% Confidence Interval 10.5 to 12.0 | Months | |
| Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 15.7 | 95% Confidence Interval 13.8 to 19.3 | Months | |
| Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10 | Placebo + Chemotherapy (FP or CAPOX Regimen) | 11.8 | 95% Confidence Interval 10.3 to 12.7 | Months | |
| Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 6.9 | 95% Confidence Interval 6.3 to 7.2 | Months | |
| Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in All Participants | Placebo + Chemotherapy (FP or CAPOX Regimen) | 5.6 | 95% Confidence Interval 5.5 to 5.7 | Months | |
Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 6.9 | 95% Confidence Interval 6.0 to 7.2 | Months | |
Progression Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) Assessed by Blinded Independent Central Review (BICR) in Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1 | Placebo + Chemotherapy (FP or CAPOX Regimen) | 5.6 | 95% Confidence Interval 5.4 to 5.7 | Months |
1 to 10 of 28Source ClinicalTrials.gov
See all 28 results by groupParticipant flow10
How many started, completed or left each group, period by period.
| Period | Milestone | Group | Participants | Units counted |
|---|---|---|---|---|
| Overall Study | STARTED | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 790 | |
| Overall Study | STARTED | Placebo + Chemotherapy (FP or CAPOX Regimen) | 789 | |
| Overall Study | Treated | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 785 | |
| Overall Study | Treated | Placebo + Chemotherapy (FP or CAPOX Regimen) | 787 | |
| Overall Study | Received Pembrolizumab Second Course | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 12 | |
| Overall Study | Received Pembrolizumab Second Course | Placebo + Chemotherapy (FP or CAPOX Regimen) | 0 | |
| Overall Study | COMPLETED | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 0 | |
| Overall Study | COMPLETED | Placebo + Chemotherapy (FP or CAPOX Regimen) | 0 | |
| Overall Study | NOT COMPLETED | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 790 | |
| Overall Study | NOT COMPLETED | Placebo + Chemotherapy (FP or CAPOX Regimen) | 789 |
Source ClinicalTrials.gov
Adverse events1,203
Each adverse event the trial posted, group by group: the participants affected out of those at risk.
| Type | Event | Organ system | Group | Affected | At risk | Events |
|---|---|---|---|---|---|---|
| other | Anaemia | Blood and lymphatic system disorders | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 325 | 785 | 512 |
| other | Anaemia | Blood and lymphatic system disorders | Placebo + Chemotherapy (FP or CAPOX Regimen) | 282 | 787 | 413 |
| other | Anaemia | Blood and lymphatic system disorders | Pembrolizumab Second Course | 3 | 12 | 4 |
| other | Leukopenia | Blood and lymphatic system disorders | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 47 | 785 | 76 |
| other | Leukopenia | Blood and lymphatic system disorders | Placebo + Chemotherapy (FP or CAPOX Regimen) | 42 | 787 | 79 |
| other | Leukopenia | Blood and lymphatic system disorders | Pembrolizumab Second Course | 2 | 12 | 3 |
| other | Lymphopenia | Blood and lymphatic system disorders | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 28 | 785 | 38 |
| other | Lymphopenia | Blood and lymphatic system disorders | Placebo + Chemotherapy (FP or CAPOX Regimen) | 16 | 787 | 25 |
| other | Lymphopenia | Blood and lymphatic system disorders | Pembrolizumab Second Course | 3 | 12 | 3 |
| other | Neutropenia | Blood and lymphatic system disorders | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 146 | 785 | 309 |
1 to 10 of 1,203Source ClinicalTrials.gov
See all 1,203 adverse eventsAdverse event totals9
The totals the trial posted for each group.
| Total | Group | Affected | At risk |
|---|---|---|---|
| Total, all-cause mortality | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 689 | 790 |
| Total, all-cause mortality | Placebo + Chemotherapy (FP or CAPOX Regimen) | 733 | 789 |
| Total, all-cause mortality | Pembrolizumab Second Course | 8 | 12 |
| Total, other adverse events | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 755 | 785 |
| Total, other adverse events | Placebo + Chemotherapy (FP or CAPOX Regimen) | 751 | 787 |
| Total, other adverse events | Pembrolizumab Second Course | 10 | 12 |
| Total, serious adverse events | Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) | 358 | 785 |
| Total, serious adverse events | Placebo + Chemotherapy (FP or CAPOX Regimen) | 317 | 787 |
| Total, serious adverse events | Pembrolizumab Second Course | 1 | 12 |
Source ClinicalTrials.gov
Papers5
The papers the trial lists on ClinicalTrials.gov.
Grants0
The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.
None in this release.
Trial comparisons2
Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.
| Comparison | Source |
|---|---|
| Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) vs Placebo + Chemotherapy (FP or CAPOX Regimen): Number of Participants Who Discontinued Study Treatment Due To an Adverse Event (AE) | Trial comparisons |
| Pembrolizumab + Chemotherapy (FP or CAPOX Regimen) vs Placebo + Chemotherapy (FP or CAPOX Regimen): Number of Participants Who Experienced an Adverse Event (AE) | Trial comparisons |
Tests0
The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.
None in this release.
Data dates
The day each source was copied for this release.
Sources 3
- ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
- ClinicalTrials.govNo license stated
- NIH RePORTER's clinical studies and project filesPublic domain
Each source's terms
- ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
- ClinicalTrials.govnone stated
- NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)
ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.
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