Participant flow

Pembrolizumab/Placebo Plus Trastuzumab Plus Chemotherapy in Human Epidermal Growth Factor Receptor 2 Positive (HER2+) Advanced Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-811/KEYNOTE-811) · Source last updated 2026-08-26

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

groups

1. description

   Participants received 200 mg pembrolizumab intravenously (IV) every 3 weeks (Q3W) plus trastuzumab (8 mg/kg loading dose, 6 mg/kg maintenance thereafter) IV Q3W in combination with cisplatin plus 5-fluorouracil (FP) or capecitabine/oxaliplatin (CAPOX) chemotherapy. Eligible participants from the Global Cohort Pembrolizumab + Standard of Care who stopped initial course of pembrolizumab due to complete response (CR) or who had stable disease (SD), PR, or CR after completion of 35 cycles of pembrolizumab but progressed after discontinuation, initiated a second course of pembrolizumab at the investigator's discretion. Participants received 200 mg pembrolizumab IV every 3 weeks (Q3W) for up to 17 additional cycles (approximately 1 year additional treatment).

   id

   FG000

   title

   Global Pembrolizumab + Standard of Care First Course

2. description

   Participants received matched placebo to pembrolizumab IV Q3W plus trastuzumab (8mg/kg loading dose, 6mg/kg maintenance thereafter) IV Q3W in combination with FP or CAPOX chemotherapy.

   id

   FG001

   title

   Global Standard of Care

3. description

   Participants received 200 mg pembrolizumab IV every 3 weeks (Q3W) plus trastuzumab (8 mg/kg loading dose, 6 mg/kg maintenance thereafter) IV Q3W in combination with SOX chemotherapy.

   id

   FG002

   title

   Japan Pembrolizumab + Trastuzumab + S-1 Plus Oxaliplatin

4. description

   Participants received matched placebo to pembrolizumab IV Q3W plus trastuzumab (8mg/kg loading dose, 6mg/kg maintenance thereafter) IV Q3W in combination with SOX chemotherapy.

   id

   FG003

   title

   Japan Trastuzumab + S-1 Plus Oxaliplatin

periods

1. drop Withdraws

   1. reasons

      1. group Id

         FG000

         num Subjects

         266

      2. group Id

         FG001

         num Subjects

         286

      3. group Id

         FG002

         num Subjects

         14

      4. group Id

         FG003

         num Subjects

         17

      type

      Death

   2. reasons

      1. group Id

         FG000

         num Subjects

         0

      2. group Id

         FG001

         num Subjects

         1

      3. group Id

         FG002

         num Subjects

         0

      4. group Id

         FG003

         num Subjects

         0

      type

      Lost to Follow-up

   3. reasons

      1. group Id

         FG000

         num Subjects

         1

      2. group Id

         FG001

         num Subjects

         3

      3. group Id

         FG002

         num Subjects

         0

      4. group Id

         FG003

         num Subjects

         0

      type

      Withdrawal by Subject

   4. reasons

      1. group Id

         FG000

         num Subjects

         83

      2. group Id

         FG001

         num Subjects

         58

      3. group Id

         FG002

         num Subjects

         6

      4. group Id

         FG003

         num Subjects

         3

      type

      Participants Ongoing

   milestones

   1. achievements

      1. group Id

         FG000

         num Subjects

         350

      2. group Id

         FG001

         num Subjects

         348

      3. group Id

         FG002

         num Subjects

         20

      4. group Id

         FG003

         num Subjects

         20

      type

      STARTED

   2. achievements

      1. group Id

         FG000

         num Subjects

         350

      2. group Id

         FG001

         num Subjects

         346

      3. group Id

         FG002

         num Subjects

         20

      4. group Id

         FG003

         num Subjects

         20

      type

      Treated

   3. achievements

      1. group Id

         FG000

         num Subjects

         11

      2. group Id

         FG001

         num Subjects

         0

      3. group Id

         FG002

         num Subjects

         0

      4. group Id

         FG003

         num Subjects

         0

      type

      Received Second Course of Pembrolizumab

   4. achievements

      1. group Id

         FG000

         num Subjects

         0

      2. group Id

         FG001

         num Subjects

         0

      3. group Id

         FG002

         num Subjects

         0

      4. group Id

         FG003

         num Subjects

         0

      type

      COMPLETED

   5. achievements

      1. group Id

         FG000

         num Subjects

         350

      2. group Id

         FG001

         num Subjects

         348

      3. group Id

         FG002

         num Subjects

         20

      4. group Id

         FG003

         num Subjects

         20

      type

      NOT COMPLETED

   title

   Overall Study

pre Assignment Details

Per protocol, response or progression for participants in the Japan-specific SOX (S-1 plus oxaliplatin) Cohort and for participants in the second course of pembrolizumab were not counted towards efficacy analysis, and adverse events for participants during the second course of pembrolizumab were not counted towards safety analysis.

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

Preserved source evidence · Not medical advice