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NCT03778931 · OUTCOME

Progression-free Survival in ESR1-mut Participants

Phase 3 Trial of Elacestrant Versus Standard of Care for the Treatment of ER+/HER2- Advanced Breast Cancer · Source last updated 2025-09-15

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
From Date of Randomization until Disease Progression or Death Due to Any Cause (up to 12 Months)

What was measured

Progression-free survival based on blinded IRC assessment in ESR1-mut participants defined as the length of time from randomization until the date of objective disease progression per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) as assessed by the blinded IRC or death from any cause. Progression is defined per RECIST v1.1 as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.

Groups in this outcome

Elacestrant

Participants in Arm 1 will receive elacestrant Elacestrant: 400 mg/day once daily oral dosing

Standard of Care (SoC)

Participants in Arm 2 will receive investigator's choice of one of the standard-of-care drugs (fulvestrant, anastrozole, letrozole, or exemestane) Standard of Care: * Fulvestrant: 500 mg administered intramuscularly (IM) into the buttocks as two 5 mL injections on C1D1, C1D15 and C2D1 and Day 1 of every subsequent 28-day cycle * Anastrozole 1 mg/day on a continuous dosing schedule * Letrozole: 2.5 mg/day on a continuous dosing schedule * Exemestane: 25 mg/day on a continuous dosing schedule

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

Analysis denominator · Participants

GroupSource count
Elacestrant115
Standard of Care (SoC)113

Reported measurements

Source class 1
Values in months · Interval/dispersion: 95% Confidence Interval
GroupValueSpreadLowerUpperComment
Elacestrant3.78Not reported2.177.26Not reported
Standard of Care (SoC)1.87Not reported1.872.14Not reported

Source statistical analyses

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

  1. ci Lower Limit
    0.387
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.768
    group Description
    The analysis was performed using a stratified Cox Proportional Hazards model with ties=Efron and the stratification factors: prior treatment with fulvestrant (yes vs no) and presence of visceral metastases (yes vs no); the CI calculated using a profile likelihood approach.
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    OTHER
    p Value
    0.0005
    param Type
    Hazard Ratio (HR)
    param Value
    0.546
    statistical Comment
    The p-value was generated by using a two-sided stratified log-rank test.
    statistical Method
    Log Rank
Complete source fields
analyses
  1. ci Lower Limit
    0.387
    ci Num Sides
    TWO_SIDED
    ci Pct Value
    95
    ci Upper Limit
    0.768
    group Description
    The analysis was performed using a stratified Cox Proportional Hazards model with ties=Efron and the stratification factors: prior treatment with fulvestrant (yes vs no) and presence of visceral metastases (yes vs no); the CI calculated using a profile likelihood approach.
    group Ids
    1. OG000
    2. OG001
    non Inferiority Type
    OTHER
    p Value
    0.0005
    param Type
    Hazard Ratio (HR)
    param Value
    0.546
    statistical Comment
    The p-value was generated by using a two-sided stratified log-rank test.
    statistical Method
    Log Rank
classes
  1. categories
    1. measurements
      1. group Id
        OG000
        lower Limit
        2.17
        upper Limit
        7.26
        value
        3.78
      2. group Id
        OG001
        lower Limit
        1.87
        upper Limit
        2.14
        value
        1.87
denoms
  1. counts
    1. group Id
      OG000
      value
      115
    2. group Id
      OG001
      value
      113
    units
    Participants
description
Progression-free survival based on blinded IRC assessment in ESR1-mut participants defined as the length of time from randomization until the date of objective disease progression per Response Evaluation Criteria In Solid Tumors Criteria (RECIST v1.1) as assessed by the blinded IRC or death from any cause. Progression is defined per RECIST v1.1 as a 20% increase in the sum of the longest diameter of target lesions, or a measurable increase in a non-target lesion, or the appearance of new lesions.
dispersion Type
95% Confidence Interval
groups
  1. description
    Participants in Arm 1 will receive elacestrant Elacestrant: 400 mg/day once daily oral dosing
    id
    OG000
    title
    Elacestrant
  2. description
    Participants in Arm 2 will receive investigator's choice of one of the standard-of-care drugs (fulvestrant, anastrozole, letrozole, or exemestane) Standard of Care: * Fulvestrant: 500 mg administered intramuscularly (IM) into the buttocks as two 5 mL injections on C1D1, C1D15 and C2D1 and Day 1 of every subsequent 28-day cycle * Anastrozole 1 mg/day on a continuous dosing schedule * Letrozole: 2.5 mg/day on a continuous dosing schedule * Exemestane: 25 mg/day on a continuous dosing schedule
    id
    OG001
    title
    Standard of Care (SoC)
param Type
MEDIAN
reporting Status
POSTED
time Frame
From Date of Randomization until Disease Progression or Death Due to Any Cause (up to 12 Months)
title
Progression-free Survival in ESR1-mut Participants
type
PRIMARY
unit Of Measure
months

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

Preserved source evidence · Not medical advice