Skip to content
Triangle logo TriangleGet started
← Full study record

NCT03221426 · OUTCOME

Pathological Complete Response (pathCR) Rate - 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
NUMBER
Unit
Percentage of Participants
Interval / dispersion
95% Confidence Interval
Time frame
Up to approximately 9 weeks following completion of neoadjuvant treatment (up to Study Week 18)

What was measured

PathCR rate was defined as the percentage of participants having a pathCR based on central review. pathCR was defined as no invasive disease within an entirely submitted and evaluated gross lesion, and histologically negative nodes. The percentage of participants having pathCR was presented for the Pembrolizumab+XP/FP and Placebo+XP/FP treatment arms.

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 Percentage of Participants · Interval/dispersion: 95% Confidence Interval
GroupValueSpreadLowerUpperComment
Pembrolizumab + XP/FP13.4Not reported10.317.2Not reported
Placebo + XP/FP2.0Not reported0.93.9Not reported

Source statistical analyses

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

  1. ci Lower Limit
    8.0
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    15.3
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    SUPERIORITY
    p Value
    <0.00001
    param Type
    Difference in Percentage
    param Value
    11.4
    statistical Comment
    Based on Miettinen \& Nurminen method stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    statistical Method
    Stratified Miettinen and Nurminen
Complete source fields
analyses
  1. ci Lower Limit
    8.0
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    15.3
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    SUPERIORITY
    p Value
    <0.00001
    param Type
    Difference in Percentage
    param Value
    11.4
    statistical Comment
    Based on Miettinen \& Nurminen method stratified by geographic region (Asia vs. Non-Asia) and tumor staging (II vs. III vs. IVa)
    statistical Method
    Stratified Miettinen and Nurminen
classes
  1. categories
    1. measurements
      1. group Id
        OG000
        lower Limit
        10.3
        upper Limit
        17.2
        value
        13.4
      2. group Id
        OG001
        lower Limit
        0.9
        upper Limit
        3.9
        value
        2.0
denoms
  1. counts
    1. group Id
      OG000
      value
      402
    2. group Id
      OG001
      value
      402
    units
    Participants
description
PathCR rate was defined as the percentage of participants having a pathCR based on central review. pathCR was defined as no invasive disease within an entirely submitted and evaluated gross lesion, and histologically negative nodes. The percentage of participants having pathCR was presented for the Pembrolizumab+XP/FP and Placebo+XP/FP treatment arms.
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
NUMBER
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 9 weeks following completion of neoadjuvant treatment (up to Study Week 18)
title
Pathological Complete Response (pathCR) Rate - Pembrolizumab+XP/FP and Placebo+XP/FP Treatment Arms
type
PRIMARY
unit Of Measure
Percentage of Participants

Download exact source JSON → · Snapshot ctgov-results-191f4516d4760045304b24a0

Preserved source evidence · Not medical advice