Phase 2 Study of Amcenestrant (SAR439859) Versus Physician's Choice in Locally Advanced or Metastatic ER-positive Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Phase 2 Study of Amcenestrant (SAR439859) Versus Physician's Choice in Locally Advanced or Metastatic ER-positive Breast Cancer (NCT04059484), a randomized phase 2 study. The primary outcome is Progression Free Survival (PFS).

2. Clinical Question

3. Trial Design

This was a randomized, parallel-group phase 2 trial comparing amcenestrant with endocrine monotherapy selected by a physician. The registry record lists an enrollment of 367. The primary outcome results presented for the main cohort include 143 participants in the amcenestrant arm and 147 in the physician-choice arm; those arm counts should not be taken as the enrollment total. Safety results also list Chinese-cohort groups.

The population was described as having estrogen receptor-positive, HER2-negative, locally advanced or metastatic breast cancer with prior exposure to hormonal therapies. The physician-choice control could include fulvestrant, an aromatase inhibitor, or an estrogen receptor modulator as monotherapy. The intervention description specifies daily oral amcenestrant under fed or fast conditions.

The record labels the trial randomized and parallel. Its official title calls it open label, while the masking field is recorded as single; the registry record does not explain this difference or identify who was masked. The study status is terminated. The registry record does not report the reason for termination, the original sample-size justification, or the trial’s original design assumptions.

The listed start date is 2019-10-22 and the listed primary completion date is 2022-02-15. The primary endpoint was progression-free survival, analyzed using the Kaplan-Meier method, with the comparison assessed by a stratified log-rank test. The record describes the primary analysis as intention-to-treat. Further detail about the stratification factors and the handling of participants who did not experience an event is not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Total 367 unique participants enrolled:290 participants(main cohort),77 new participants(Chinese cohort).Randomization was stratified:presence of visceral metastasis(atleast 1 liver/lung metastasis;yes/no),prior treatment with cyclin-dependent kinase 4/6(CDK4/6) inhibitors(yes/no),Eastern Cooperative Oncology Group(ECOG) status(0/1).Study was terminated as it did not meet primary objective of improved progression free survival with amcenestrant versus endocrine treatment of physician's choice.

Main Cohort

Reasons for not completing this period:

Chinese Cohort

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was performed on the ITT population.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

Population: Analysis was performed on intent to treat (ITT) population which included all enrolled participants (i.e., who sign the informed consent form \[ICF\]) and for whom there is a confirmation of successful allocation of a randomization number by interactive response technology (IRT). 7 and 6 participants were included in PCEM-Chinese Cohort \& Amcenestrant-Chinese Cohort, respectively from the Main Cohort. Therefore, baseline measure data are reported for each cohort separately.

6. Primary Endpoint

The registry lists the primary outcome as Progression Free Survival (PFS), measured over From randomization to the date of first documented tumor progression or death due to any cause or data cut-off date whichever comes first (maximum duration: 116 weeks).

Progression-free survival measures the time from randomization until the first documented tumor progression or death from any cause, whichever occurs first. Progression was assessed using RECIST 1.1 by independent central review. The registry description also refers to a data cut-off, with a maximum duration of 116 weeks. Participants without a recorded progression or death by the applicable cut-off contribute information up to the point at which follow-up ends.

This time-to-event outcome is used because it incorporates both whether an event occurred and when it occurred. It can use information from participants whose follow-up ends before an event is observed, rather than reducing follow-up to a simple count of events. Kaplan-Meier methods estimate the progression-free survival pattern over time and support the reported median, the time by which the estimated event-free proportion reaches its midpoint.

The endpoint is not the same as overall survival: progression or death can define a progression-free survival event, whereas overall survival concerns death. The registry lists overall survival as a secondary outcome. The posted primary comparison reports medians of 3.7 months for physician-choice endocrine monotherapy and 3.6 months for amcenestrant, with a hazard ratio, confidence interval, and p-value from the stratified log-rank analysis.

7. Results Posted in the Registry

• Physician Choice Endocrine Monotherapy (PCEM)- Main Cohort vs Amcenestrant- Main Cohort: hazard ratio 1.05 (95% CI 0.79–1.40), reported p = 0.644 (as reported in the registry).

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Percentage of Participants With Objective Response

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Amcenestrant- Main Cohort: 11.9% (17/143) versus 8.8% (13/147) on control; risk difference 3.0 percentage points (95% CI -4.0 to 10.1), risk ratio 1.34 (0.68–2.67); unadjusted two-proportion z-test p = 0.395.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Amcenestrant- Main Cohort and the control. The interval gives the range of effects that remain compatible with the data.

Percentage of Participants With Disease Control

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Amcenestrant- Main Cohort: 54.5% (78/143) versus 53.7% (79/147) on control; risk difference 0.8 percentage points (95% CI -10.7 to 12.3), risk ratio 1.01 (0.82–1.25); unadjusted two-proportion z-test p = 0.891.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Amcenestrant- Main Cohort and the control. The interval gives the range of effects that remain compatible with the data.

Percentage of Participants With Clinical Benefit

• Endpoint type: Binary: the percentage of participants with the event (counts rebuilt from the posted percentages and group sizes).
• Test: Unadjusted two-proportion z-test, with a Wald 95% confidence interval for the risk difference.
• Result:
  • Amcenestrant- Main Cohort: 27.3% (39/143) versus 29.3% (43/147) on control; risk difference -2.0 percentage points (95% CI -12.3 to 8.4), risk ratio 0.93 (0.65–1.35); unadjusted two-proportion z-test p = 0.708.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Amcenestrant- Main Cohort and the control. The interval gives the range of effects that remain compatible with the data.

The posted secondary outcomes cover response, disease control, clinical benefit, overall survival, duration of response, ESR1 mutation subgroups, pharmacokinetics, and other measures. The registry record lists multiple secondary measures, while the posted numerical comparisons described in the results include objective response, disease control, and clinical benefit. This broader set of outcomes gives a view of different aspects of the study, but not all are direct substitutes for progression-free survival.

Across the posted secondary binary comparisons, the estimates do not form a single consistent pattern that would overturn or sharpen the primary time-to-event result. Their uncertainty is substantial, and the record lists no sponsor-reported analyses for these binary comparisons. The primary outcome remains the formal time-to-event comparison, while secondary results are supporting context rather than a separate basis for a definitive conclusion.

Unadjusted secondary results carry less weight when many outcomes are examined because the chance of at least one apparently unusual result increases as the number of tests grows. In general, multiplicity procedures can control that issue, but the registry record does not report a correction strategy or a hierarchy for the secondary outcomes. The unadjusted p-values should therefore be read as exploratory evidence, not as if each were the sole pre-specified test.

The registry lists other secondary outcomes, but numerical results for them are not included in the posted results described in this record. Their absence from the posted results is not evidence that no events or measurements occurred; the results are simply not reported in the registry record.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Overall Survival (OS)
• Percentage of Participants With Objective Response
• Percentage of Participants With Disease Control
• Percentage of Participants With Clinical Benefit
• Duration of Response (DOR)
• Progression Free Survival (PFS) According to Estrogen Receptor 1 Gene (ESR1) Mutation Status
• Pharmacokinetics: Plasma Concentrations of Amcenestrant
• Within-Participant Steady State Ctrough of Amcenestrant

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is time to progression or death, analyzed with Kaplan-Meier methods. This approach estimates the probability of remaining free of the defined event over follow-up while accounting for participants whose event status is not observed for the entire follow-up period. The registry record describes progression as assessed by RECIST 1.1 through independent central review and defines death from any cause as an event. It also identifies the intention-to-treat population for this analysis.

What does the Kaplan-Meier median represent?

The Kaplan-Meier median is the time at which the estimated progression-free survival curve reaches its midpoint. It is a concise description of each group’s event-time distribution, not an average follow-up time and not a summary of every point on the curve. A median can be similar across groups even if their curves differ at other times, and it does not on its own quantify the uncertainty in the comparison. For that reason, the reported hazard ratio, confidence interval, and log-rank result are also relevant.

How should the hazard ratio be read?

The registry reports a hazard ratio for physician-choice endocrine monotherapy versus amcenestrant. In general, a hazard ratio compares the event rates between groups over time under a time-to-event model. A value of 1 corresponds to equal hazards; values on either side indicate a relative contrast whose direction is determined by the stated group order. The hazard ratio is not a comparison of medians and does not give an absolute difference in event-free time. The posted estimate is 1.051, and its 95% confidence interval is 0.789 to 1.4.

What does the stratified log-rank test contribute?

The sponsor reports a stratified log-rank test for the primary comparison. In general, a log-rank test compares observed and expected event patterns over follow-up. Stratification means the comparison accounts for defined groups in the test, but the factors used for stratification are not reported in the registry record. The reported p-value is 0.644. A p-value describes how compatible the observed test result is with a specified null model; it is not the probability that a treatment is effective or that the null model is true.

For secondary binary outcomes, the posted results give percentages with 95% confidence intervals and unadjusted comparisons. A risk difference expresses the difference between group proportions on an absolute scale. In general, its confidence interval indicates the range of contrasts compatible with the data and method used. These unadjusted summaries do not account for testing multiple outcomes, and the record does not report sponsor analyses for those secondary comparisons.

Confidence intervals communicate uncertainty around an estimate. A wide interval indicates that a range of effects remains compatible with the data; an interval spanning the null value does not establish that the true effect is exactly null. For a hazard ratio, the null value is 1. For a risk difference, the null value is 0. These are general interpretations; the actual reported interval and analysis method should be considered for each outcome.

Over-dispersion is a general concern when variability in data exceeds what a chosen model assumes. If present and not accommodated, uncertainty estimates may be too narrow. The registry record does not report an over-dispersion assessment for these analyses, and the posted primary outcome is a time-to-event endpoint analyzed by Kaplan-Meier and stratified log-rank methods rather than a count outcome.

The registry record does not report details of censoring rules beyond the endpoint timeframe, the stratification factors, an interim analysis plan, or a complete statistical analysis plan. It also does not report how missing data were handled for each secondary outcome. Those details cannot be inferred from the posted estimates.

11. Confidence Intervals and Precision

The primary hazard-ratio estimate is 1.051, with a 95% confidence interval from 0.789 to 1.4. The interval includes 1, so the data are compatible with a range of relative hazards on both sides of the null value. Its breadth indicates that the primary estimate is not precise enough to distinguish a modest contrast in either direction from no relative difference. The reported p-value, 0.644, is consistent with the absence of strong statistical evidence against the null in this test.

The group medians are 3.7 months for physician-choice endocrine monotherapy and 3.6 months for amcenestrant. A median is a point estimate; it does not convey the uncertainty of the whole comparison. The registry record does not post confidence intervals for these medians in the primary outcome information. The hazard-ratio confidence interval is therefore important for understanding uncertainty in the comparative time-to-event analysis, though it describes a different summary than the medians.

For the secondary binary outcomes, the posted confidence intervals also show appreciable uncertainty. In general, an interval spanning the null value is compatible with no group difference as well as with effects in either direction. The secondary estimates should not be interpreted as precise evidence of a difference solely from their point estimates.

A confidence interval is not a guarantee that the true value lies within the interval, nor does it give the probability that a particular hypothesis is true. It describes uncertainty under the analysis method and assumptions used. The registry record does not provide additional sensitivity analyses that would show how robust the intervals are to alternative assumptions.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The sample-size illustrations are planning calculations based on the observed effects, not the trial’s own design calculations. For the primary time-to-event outcome, the figures are total events, not participants per arm. For the posted binary secondary outcomes, the figures are participants per arm. The distinction matters: event targets in a time-to-event analysis are not interchangeable with total enrollment, while per-arm figures describe a group size for a binary-outcome planning scenario.

The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The scenarios use 100%, 75%, or 50% of the observed effect as the effect to detect. The time-to-event planning calculations use the Schoenfeld method and express the target as total events. The other planning calculations express the target as participants per arm.

The 80% power column gives the planned event count or group size that would correspond to an 80% chance of detecting the specified effect under those assumptions, if that effect and the assumptions held. The 90% column gives the corresponding planning target for a 90% chance. These are design illustrations, not descriptions of the achieved chance of detecting an effect in this trial.

Smaller effects are harder to distinguish from random variation, so the illustrations require more events or participants as the assumed effect is reduced from 100% to 75% or 50% of the observed effect. These calculations are not observed power. The trial’s original sample-size justification and original design assumptions are not reported in the registry record.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

d is the total number of events needed (Schoenfeld's formula) with 1:1 allocation and proportional hazards.

Worked calculation for this trial

1. Hazard ratio HR = 1.051, so ln(HR) = 0.0497.
2. d = 4 × (1.96 + 0.842)² / [ln(1.051)]² = 12,688.8, rounded up to 12,689 events in total for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
hr <- 1.051                              # observed hazard ratio
events_needed <- function(power, frac = 1) ceiling(round(4 * (z_a + qnorm(power))^2 / log(hr^frac)^2, 6))   # Schoenfeld, 1:1 allocation
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: events = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(events_needed(0.80, f), big.mark = ","), format(events_needed(0.90, f), big.mark = ",")))

# Simulation: given d total events under proportional hazards, events in the treatment arm are Binomial(d, hr / (1 + hr)).
# The score (log-rank type) statistic is (D1 - d / 2) / sqrt(d / 4).
set.seed(4059484)
d    <- events_needed(0.80)
reps <- 20000
D1 <- rbinom(reps, d, hr / (1 + hr))
z  <- (D1 - d / 2) / sqrt(d / 4)
cat(sprintf("Simulated power with %s events: %.3f (%d replicates)\n", format(d, big.mark = ","), mean(abs(z) > z_a), reps))

Output from running the code

100% of observed effect: events = 12,689 (80% power), 16,987 (90% power)
 75% of observed effect: events = 22,558 (80% power), 30,199 (90% power)
 50% of observed effect: events = 50,756 (80% power), 67,947 (90% power)
Simulated power with 12,689 events: 0.800 (20000 replicates)

The simulation uses the fact that, with d events in total and proportional hazards, the number of events in the treatment arm is binomial. It is an approximation that conditions on the total number of events, and it should land close to the target power.

14. Analyses Reported by the Sponsor

The primary comparison is the sponsor-reported analysis: a hazard ratio of 1.051, with a 95% confidence interval from 0.789 to 1.4 and p = 0.644 from a stratified log-rank test. For this time-to-event endpoint, the analysis uses the sponsor’s reported hazard ratio rather than an independently recalculated estimate. The reported result is the appropriate primary estimate to interpret.

The registry record does not flag a discrepancy between the posted primary result and a recalculation. The secondary binary-outcome comparisons are posted as unadjusted summaries, but the record lists no sponsor-reported analysis for those comparisons. Those calculations should not be mistaken for the sponsor’s formal analysis or for an adjusted confirmatory test.

The primary estimate’s interpretation depends on its stated group order: physician-choice endocrine monotherapy versus amcenestrant. The confidence interval includes the hazard-ratio null value of 1, and the reported p-value does not indicate strong evidence against that null. Neither point estimate nor p-value alone establishes equivalence, and the registry record does not report an equivalence or non-inferiority analysis.

15. Multiplicity, Missing Data and Analysis Populations

The registry record describes one primary endpoint, progression-free survival, and reports a stratified log-rank analysis. It lists a broad set of secondary outcomes, including overall survival, response-related outcomes, ESR1 mutation status, pharmacokinetics, and quality of life in the study objectives. The posted numerical results include only some of these outcomes. The record does not report a multiplicity adjustment, a testing hierarchy, or a procedure for controlling the family-wise error rate across secondary comparisons.

Multiplicity matters because examining many outcomes or subgroups creates more opportunities for chance findings. An unadjusted p-value assesses a single comparison under its own test assumptions; it does not account for the full set of comparisons if many are considered together. Therefore, the secondary unadjusted results are best viewed as exploratory unless a separate analysis plan establishes how they were intended to be interpreted. Such a plan is not reported in the registry record.

The primary endpoint analysis is identified as intention-to-treat. In general, this population approach analyzes participants according to their randomized group, preserving the original comparison. The registry record does not provide further detail about the exact analysis set, deviations from assigned treatment, or exclusions, so the specific implementation cannot be evaluated from the posted information alone.

The record defines progression-free survival events and states the endpoint timeframe, but further details on censoring and missing assessments are not reported. For the secondary endpoints, the record does not describe missing-data methods, imputation, or sensitivity analyses. It also does not report an interim-analysis plan or the original statistical analysis plan. These gaps limit assessment of how incomplete follow-up, missing outcome measurements, or multiple testing may affect interpretation.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: disease progression (3.5%), dyspnoea (2.7%), pleural effusion (2.4%), rib fracture (2.4%), pathological fracture (2.1%).

The serious adverse event figures give the number of participants at risk and the number affected in each listed group. In the main cohort, the record lists 147 at risk and 16 affected in the physician-choice group, and 143 at risk and 25 affected in the amcenestrant group. The Chinese-cohort figures are 42 at risk and 2 affected for physician choice, and 48 at risk and 5 affected for amcenestrant. These are counts as recorded, not comparative risk estimates adjusted for follow-up or other factors.

The registry also lists deaths by group, but the posted figures do not establish that those deaths were caused by treatment or were classified as serious adverse events. The most frequently listed serious adverse event terms include disease progression, dyspnoea, pleural effusion, rib fracture, pathological fracture, and cancer pain, with the percentages shown in the safety results. These terms and percentages describe reported events; they do not by themselves establish causation.

Safety counts should be interpreted with attention to the group sizes and the study’s follow-up and reporting definitions. Those additional details are not fully reported in the registry record, so the counts alone do not support a complete comparative safety assessment.

17. What the Result Does, and Does Not, Mean

The primary result describes a comparison of progression-free survival between two randomized main-cohort groups. The reported medians are 3.7 months for physician-choice endocrine monotherapy and 3.6 months for amcenestrant. The sponsor-reported hazard ratio is 1.051, with a 95% confidence interval from 0.789 to 1.4 and p = 0.644. Together, these estimates show that the posted analysis does not provide strong statistical evidence of a difference in the primary time-to-event outcome.

That finding does not prove that the treatments have identical effects. The confidence interval includes the null value but also spans values on either side, leaving uncertainty about the comparative hazard. A non-significant test is not an equivalence test. The registry record does not report an equivalence or non-inferiority framework, and the available result cannot establish that any possible difference is clinically unimportant.

The primary endpoint is progression-free survival, not overall survival. Although overall survival and other outcomes are listed among the objectives, their numerical results are not all reported in the registry record. The posted secondary comparisons are unadjusted and should be interpreted cautiously in light of the number of outcomes considered.

The record’s terminated status is a study status, not an explanation of why the trial ended. The reason for termination is not reported in the registry record. The posted information also does not give the original sample-size justification, a full missing-data plan, or enough detail to assess every aspect of analysis conduct. Conclusions should remain tied to the reported endpoint, groups, and methods rather than extending to unreported outcomes or reasons for study status.

18. Why This Trial Matters Statistically

This trial illustrates why a treatment comparison should be read through its endpoint, estimate, and uncertainty together. The medians provide a compact description of progression-free survival in each main-cohort group, while the hazard ratio summarizes the relative time-to-event contrast and the confidence interval shows how uncertain that estimate is. A single point estimate or p-value cannot substitute for this combined reading.

It also highlights the distinction between a primary analysis and a collection of secondary outcomes. Several secondary measures can add clinical and statistical context, but unadjusted comparisons do not carry the same inferential weight as a designated primary test when multiplicity handling is not reported. A pattern across outcomes needs to be interpreted with both their definitions and their uncertainty in view.

The planning illustrations demonstrate another important distinction: sample-size calculations are conditional on assumptions about the effect, allocation, significance level, and statistical approximation. Illustrations based on an observed effect are not evidence that a study was originally planned around that effect, and they are not observed power. The original design justification is not reported in the registry record.

Finally, the record shows why completeness matters. The primary method and population are identified, but details about missing data, stratification factors, multiplicity, interim analyses, and the reason for termination are not reported. Such information affects how fully readers can assess the robustness and intended interpretation of results.

19. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record provides a limited account of the trial’s design and analysis. Although it identifies randomization, a parallel-group model, and a primary intention-to-treat analysis, further details about randomization procedures, allocation concealment, stratification factors, and who was masked are not reported. The official title describes the trial as open label, whereas the masking field records single masking; the record does not explain the difference.

The reason for the terminated study status is not reported. The record also does not report the original sample-size justification, trial-specific design assumptions, interim analyses, or a complete statistical analysis plan. Consequently, the planning illustrations based on the observed effect should not be interpreted as the trial’s intended design.

Further details about censoring, missing outcome data, sensitivity analyses, and handling of missing assessments are not reported. The record identifies the primary analysis population and endpoint method, but that is not enough to assess all analytic decisions. Numerical results for several listed secondary outcomes are not reported in the registry record, and no multiplicity procedure is specified.

The safety information gives counts and selected serious adverse event terms, but the posted record does not provide enough detail to assess timing, exposure-adjusted rates, event attribution, or the full comparative safety profile. These limitations restrict conclusions to the results and definitions actually reported.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Phase 2 Study of Amcenestrant (SAR439859) Versus Physician's Choice in Locally Advanced or Metastatic ER-positive Breast Cancer — NCT04059484.
• Registry record last updated 2026-02-24; status last verified 2026-02.
• Results first posted 2023-03-30.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

23. Record Summary

NCT04059484 is a randomized phase 2 parallel-group trial of amcenestrant versus physician-choice endocrine monotherapy in participants with locally advanced or metastatic ER-positive, HER2-negative breast cancer and prior hormonal therapy exposure. The listed enrollment is 367, and the study status is terminated.

The primary endpoint was progression-free survival, analyzed in the intention-to-treat population using Kaplan-Meier methods. The reported main-cohort medians were 3.7 months for physician-choice monotherapy and 3.6 months for amcenestrant. The sponsor-reported hazard ratio was 1.051, with a 95% confidence interval from 0.789 to 1.4 and p = 0.644.

The record lists secondary efficacy, pharmacokinetic, quality-of-life, and safety objectives. Some secondary numerical results and serious adverse event counts are posted; other details, including the reason for termination, the original sample-size justification, multiplicity procedures, and missing-data methods, are not reported in the registry record.