CompletedPhase 3

Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859)

United States, Argentina, Australia1,579 participantsStarted 2018-11-08

Plain-language summary

The purpose of this study is to evaluate the efficacy of pembrolizumab (MK-3745) in combination with chemotherapy (Cisplatin combined with 5-Fluorouracil \[FP regimen\] or oxaliplatin combined with capecitabine \[CAPOX regimen\]) versus placebo in combination with chemotherapy (FP or CAPOX regimens) in the treatment of human epidermal growth factor receptor 2 (HER2) negative advanced gastric or GEJ adenocarcinoma in adult participants. The primary hypotheses of this study are that pembrolizumab plus chemotherapy is superior to placebo plus chemotherapy in terms of overall survival (OS). Once a participant has achieved the study objective or the study has ended, the participant will be discontinued from this study and enrolled in an extension study (Keynote 587; NCT03486873) to continue protocol-defined assessments and treatment.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria * Has histologically or cytologically confirmed diagnosis of locally advanced unresectable or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma with known programmed cell death ligand 1 (PD-L1) expression status * Has human epidermal growth factor receptor 2 (HER2) negative cancer * Male participants must agree to use contraception during the treatment period and through 95 days after the last dose of chemotherapy, refrain from donating sperm, and be abstinent from heterosexual intercourse, as their preferred and usual lifestyle, and agree to remain abstinent or must agree to use contraception per study protocol unless confirmed to be azoospermic during this period * Female participants who are not pregnant, not breastfeeding, and at least one of the following conditions applies: not a woman of childbearing potential (WOCBP) OR is a WOCBP who agrees to use contraception or be abstinent from heterosexual intercourse, as their preferred and usual lifestyle, during the treatment period and through 180 days after the last dose of chemotherapy or through 120 days after the last dose of pembrolizumab, whichever is last, and agrees not to donate eggs to others or freeze/store for her own use for the purpose of reproduction during this period * Has measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) as assessed by investigator assessment * Has provided archival tumor tissue sample or newly obtained core o…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Overall Survival (OS) in All Participants

Timeframe: Up to 45.9 months

Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1

Timeframe: Up to 45.9 months

Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10

Timeframe: Up to 45.9 months

Trial details

NCT IDNCT03675737

SponsorMerck Sharp & Dohme LLC

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2022-10-03

Results submitted2023-09-20

View on ClinicalTrials.gov More Stomach Neoplasms trials

Plain-language summary

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

What they're measuring

Overall Survival (OS) in All Participants

Timeframe: Up to 45.9 months

Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥1

Timeframe: Up to 45.9 months

Overall Survival (OS) In Participants With Programmed Cell Death Ligand 1 (PD-L1) Combined Positive Score (CPS) ≥10

Timeframe: Up to 45.9 months