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NCT03765918 · OUTCOME

Event-free Survival (EFS)

Study of Pembrolizumab Given Prior to Surgery and in Combination With Radiotherapy Given Post-surgery for Advanced Head and Neck Squamous Cell Carcinoma (MK-3475-689) · Source last updated 2026-07-31

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 ~66 months

What was measured

EFS was based on Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as assessed by blinded independent central review (BICR) and was defined as the time from randomization to any of the following events: radiographic disease progression (RDP; participants who undergo a definitive biopsy of the progressed lesion and are found to have no histologic evidence of invasive cancer will not meet criteria for an event), RDP during the neoadjuvant phase that precluded surgery, local or distant disease progression or recurrence (as assessed with imaging or biopsy as indicated), or death due to any cause. A secondary malignancy was not considered an EFS event. Per protocol, RECIST 1.1 was modified to allow up to 10 target lesions total (up to 5 per organ). Per protocol, EFS per RECIST 1.1 as assessed by BICR in all randomized participants was presented.

Analysis population: Efficacy analysis population, which included all randomized participants. Per protocol, two participants in the SOC arm received neoadjuvant treatment in error (protocol deviations) and were included in the SOC arm for efficacy analysis.

Groups in this outcome

Pembrolizumab + Standard of Care (SOC)

Neoadjuvant treatment: Participants received 200 mg pembrolizumab by intravenous (IV) infusion administered on Day 1 of a 21-day cycle for 2 cycles (up to 6 weeks) prior to surgery. Adjuvant treatment: Following surgical resection, participants received 200 mg pembrolizumab, IV infusion, on Day 1 of a 21-day cycle for 15 cycles (up to 45 weeks) plus investigator's choice of SOC treatment regimen consisting of radiotherapy, with or without cisplatin 100 mg/m\^2, IV infusion, on Day 1 of a 21-day cycle for 3 cycles (up to 9 weeks).

Standard of Care (SOC)

Adjuvant treatment: Following surgical resection, participants received investigator's choice of SOC treatment regimen consisting of radiotherapy, with or without cisplatin 100 mg/m\^2, IV infusion, on Day 1 of a 21-day cycle for 3 cycles (up to 9 weeks).

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 + Standard of Care (SOC)363
Standard of Care (SOC)351

Reported measurements

Source class 1
Values in Months · Interval/dispersion: 95% Confidence Interval
GroupValueSpreadLowerUpperComment
Pembrolizumab + Standard of Care (SOC)51.8Not reported37.5NANA = upper limit not reached due to insufficient number of participants with an event.
Standard of Care (SOC)30.4Not reported21.850.1Not reported

Source statistical analyses

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

  1. ci Lower Limit
    0.58
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.92
    group Ids
    1. OG000
    2. OG001
    non Inferiority Comment
    Hazard ratio (HR) and associated 95% confidence interval (CI) were based on Cox regression model with Efron's method of tie handling with treatment as a covariate stratified by primary tumor site and tumor stage.
    non Inferiority Type
    SUPERIORITY
    p Value
    0.00411
    param Type
    Hazard Ratio (HR)
    param Value
    0.73
    statistical Comment
    One-sided p-value was based on log-rank test stratified by primary tumor site and tumor stage.
    statistical Method
    Stratified Log Rank
Complete source fields
analyses
  1. ci Lower Limit
    0.58
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.92
    group Ids
    1. OG000
    2. OG001
    non Inferiority Comment
    Hazard ratio (HR) and associated 95% confidence interval (CI) were based on Cox regression model with Efron's method of tie handling with treatment as a covariate stratified by primary tumor site and tumor stage.
    non Inferiority Type
    SUPERIORITY
    p Value
    0.00411
    param Type
    Hazard Ratio (HR)
    param Value
    0.73
    statistical Comment
    One-sided p-value was based on log-rank test stratified by primary tumor site and tumor stage.
    statistical Method
    Stratified Log Rank
classes
  1. categories
    1. measurements
      1. comment
        NA = upper limit not reached due to insufficient number of participants with an event.
        group Id
        OG000
        lower Limit
        37.5
        upper Limit
        NA
        value
        51.8
      2. group Id
        OG001
        lower Limit
        21.8
        upper Limit
        50.1
        value
        30.4
denoms
  1. counts
    1. group Id
      OG000
      value
      363
    2. group Id
      OG001
      value
      351
    units
    Participants
description
EFS was based on Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as assessed by blinded independent central review (BICR) and was defined as the time from randomization to any of the following events: radiographic disease progression (RDP; participants who undergo a definitive biopsy of the progressed lesion and are found to have no histologic evidence of invasive cancer will not meet criteria for an event), RDP during the neoadjuvant phase that precluded surgery, local or distant disease progression or recurrence (as assessed with imaging or biopsy as indicated), or death due to any cause. A secondary malignancy was not considered an EFS event. Per protocol, RECIST 1.1 was modified to allow up to 10 target lesions total (up to 5 per organ). Per protocol, EFS per RECIST 1.1 as assessed by BICR in all randomized participants was presented.
dispersion Type
95% Confidence Interval
groups
  1. description
    Neoadjuvant treatment: Participants received 200 mg pembrolizumab by intravenous (IV) infusion administered on Day 1 of a 21-day cycle for 2 cycles (up to 6 weeks) prior to surgery. Adjuvant treatment: Following surgical resection, participants received 200 mg pembrolizumab, IV infusion, on Day 1 of a 21-day cycle for 15 cycles (up to 45 weeks) plus investigator's choice of SOC treatment regimen consisting of radiotherapy, with or without cisplatin 100 mg/m\^2, IV infusion, on Day 1 of a 21-day cycle for 3 cycles (up to 9 weeks).
    id
    OG000
    title
    Pembrolizumab + Standard of Care (SOC)
  2. description
    Adjuvant treatment: Following surgical resection, participants received investigator's choice of SOC treatment regimen consisting of radiotherapy, with or without cisplatin 100 mg/m\^2, IV infusion, on Day 1 of a 21-day cycle for 3 cycles (up to 9 weeks).
    id
    OG001
    title
    Standard of Care (SOC)
param Type
MEDIAN
population Description
Efficacy analysis population, which included all randomized participants. Per protocol, two participants in the SOC arm received neoadjuvant treatment in error (protocol deviations) and were included in the SOC arm for efficacy analysis.
reporting Status
POSTED
time Frame
Up to ~66 months
title
Event-free Survival (EFS)
type
PRIMARY
unit Of Measure
Months

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Preserved source evidence · Not medical advice