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NCT03221426 · OUTCOME

Event-free Survival (EFS) Per Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1) - Pembrolizumab+XP/FP and Placebo+XP/FP Treatment Arms

Study of Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants With Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-585/KEYNOTE-585) · Source last updated 2026-03-09

Results reported by the registry submitting party. Population, time horizon, units and missing values must be read together.

Measure
MEDIAN
Unit
Months
Interval / dispersion
95% Confidence Interval
Time frame
Up to approximately 75 months

What was measured

EFS was based on RECIST 1.1 as assessed by the investigator and was defined as the time from randomization to the first of the following events: radiographic disease progression per RECIST 1.1; local or distant recurrence as assessed by computer tomography (CT) scan or biopsy if indicated (for participants who were disease free after surgery); clinical progression as evidenced by peritoneal carcinomatosis confirmed by preoperative laparoscopy or laparotomy (for participants who were confirmed to be free of peritoneal involvement by laparoscopy at screening); or death due to any cause. A second primary malignancy, or radiographic progressive disease (PD) during the neoadjuvant phase that does not preclude successful surgery (i.e., disease free after surgery), were not considered EFS events.

Analysis population: The analysis population consisted of all randomized participants in the Pembrolizumab+XP/FP and Placebo+XP/FP treatment arms, as pre-specified per protocol.

Groups in this outcome

Pembrolizumab + XP/FP

XP=cisplatin+capecitabine and FP=cisplatin+5-fluorouracil. Neoadjuvant: Prior to surgery, participants received 3 cycles of pembrolizumab 200 mg via intravenous (IV) infusion on Day 1 of each 3-week cycle (Q3W) PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets twice each day (BID) on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle. Adjuvant: 4 to 10 weeks post-surgery, participants received 3 cycles of pembrolizumab 200 mg via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle, followed by pembrolizumab monotherapy 200 mg via IV infusion on Day 1 Q3W for up to 11 additional cycles.

Placebo + XP/FP

Neoadjuvant: Prior to surgery, participants received 3 cycles of placebo (normal saline solution) via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle. Adjuvant: 4 to 10 weeks post-surgery, participants received 3 cycles of placebo via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle, followed by placebo monotherapy via IV infusion on Day 1 Q3W for up to 11 additional cycles.

Group identifiers and denominators belong to this outcome only. They may differ in another outcome or in safety reporting.

Analysis denominator · Participants

GroupSource count
Pembrolizumab + XP/FP402
Placebo + XP/FP402

Reported measurements

Source class 1
Values in Months · Interval/dispersion: 95% Confidence Interval
GroupValueSpreadLowerUpperComment
Pembrolizumab + XP/FP44.4Not reported33.069.8Not reported
Placebo + XP/FP25.7Not reported20.836.5Not reported

Source statistical analyses

Group order, estimate direction, methods and comments are retained. No treatment ranking is inferred.

  1. ci Lower Limit
    0.67
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.98
    estimate Comment
    Cox regression model with Efron's method of tie handling with treatment as a covariate stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    SUPERIORITY
    p Value
    0.01501
    p Value Comment
    One-sided p-value based on log-rank test stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    param Type
    Hazard Ratio (HR)
    param Value
    0.81
    statistical Method
    Log Rank
Complete source fields
analyses
  1. ci Lower Limit
    0.67
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.98
    estimate Comment
    Cox regression model with Efron's method of tie handling with treatment as a covariate stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    SUPERIORITY
    p Value
    0.01501
    p Value Comment
    One-sided p-value based on log-rank test stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    param Type
    Hazard Ratio (HR)
    param Value
    0.81
    statistical Method
    Log Rank
classes
  1. categories
    1. measurements
      1. group Id
        OG000
        lower Limit
        33.0
        upper Limit
        69.8
        value
        44.4
      2. group Id
        OG001
        lower Limit
        20.8
        upper Limit
        36.5
        value
        25.7
denoms
  1. counts
    1. group Id
      OG000
      value
      402
    2. group Id
      OG001
      value
      402
    units
    Participants
description
EFS was based on RECIST 1.1 as assessed by the investigator and was defined as the time from randomization to the first of the following events: radiographic disease progression per RECIST 1.1; local or distant recurrence as assessed by computer tomography (CT) scan or biopsy if indicated (for participants who were disease free after surgery); clinical progression as evidenced by peritoneal carcinomatosis confirmed by preoperative laparoscopy or laparotomy (for participants who were confirmed to be free of peritoneal involvement by laparoscopy at screening); or death due to any cause. A second primary malignancy, or radiographic progressive disease (PD) during the neoadjuvant phase that does not preclude successful surgery (i.e., disease free after surgery), were not considered EFS events.
dispersion Type
95% Confidence Interval
groups
  1. description
    XP=cisplatin+capecitabine and FP=cisplatin+5-fluorouracil. Neoadjuvant: Prior to surgery, participants received 3 cycles of pembrolizumab 200 mg via intravenous (IV) infusion on Day 1 of each 3-week cycle (Q3W) PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets twice each day (BID) on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5-fluorouracil (5FU) 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle. Adjuvant: 4 to 10 weeks post-surgery, participants received 3 cycles of pembrolizumab 200 mg via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle, followed by pembrolizumab monotherapy 200 mg via IV infusion on Day 1 Q3W for up to 11 additional cycles.
    id
    OG000
    title
    Pembrolizumab + XP/FP
  2. description
    Neoadjuvant: Prior to surgery, participants received 3 cycles of placebo (normal saline solution) via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle. Adjuvant: 4 to 10 weeks post-surgery, participants received 3 cycles of placebo via IV infusion on Day 1 Q3W PLUS cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and capecitabine 1000 mg/m\^2 via oral tablets BID on Days 1 to 14 of each 3-week cycle OR cisplatin 80 mg/m\^2 via IV infusion on Day 1 Q3W and 5FU 800 mg/m\^2 via continuous IV infusion on Days 1 to 5 of each 3-week cycle, followed by placebo monotherapy via IV infusion on Day 1 Q3W for up to 11 additional cycles.
    id
    OG001
    title
    Placebo + XP/FP
param Type
MEDIAN
population Description
The analysis population consisted of all randomized participants in the Pembrolizumab+XP/FP and Placebo+XP/FP treatment arms, as pre-specified per protocol.
reporting Status
POSTED
time Frame
Up to approximately 75 months
title
Event-free Survival (EFS) Per Response Criteria in Solid Tumors Version 1.1 (RECIST 1.1) - Pembrolizumab+XP/FP and Placebo+XP/FP Treatment Arms
type
PRIMARY
unit Of Measure
Months

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Preserved source evidence · Not medical advice