Phase 1/2 Study of Amcenestrant (SAR439859) Single Agent and in Combination With Other Anti-cancer Therapies in Postmenopausal Women With Estrogen Receptor Positive Advanced Breast Cancer (AMEERA-1)

November 6, 2025 updated by: Sanofi

A Phase 1/2 Study for the Safety, Efficacy, Pharmacokinetic and Pharmacodynamics Evaluation of Amcenestrant (SAR439859), Administered Orally as Monotherapy, Then in Combination With Other Anti-cancer Therapies in Postmenopausal Women With Estrogen Receptor-positive Advanced Breast Cancer

Primary Objectives:

Dose Escalation:

  • To assess the incidence rate of dose-limiting toxicity (DLT) and to determine the maximum tolerated dose (MTD) as well as the recommended dose (RD) of amcenestrant administered as monotherapy and in combination with palbociclib
  • To assess the incidence rate of DLT and determine the RD of everolimus or abemaciclib in combination with the selected amcenestrant dose for the combination therapy

Safety Run-In:

- To confirm the RD of amcenestrant in combination with alpelisib

Dose Expansion:

  • Antitumor activity using objective response rate (ORR)
  • Overall safety profile of amcenestrant administered in combination with palbociclib, alpelisib, everolimus, and abemaciclib

Secondary Objectives:

  • Overall safety profile of amcenestrant monotherapy and in combination
  • Pharmacokinetic (PK) profile of amcenestrant administered as monotherapy or in combination and PK profile of palbociclib, alpelisib, everolimus and abemaciclib
  • Antitumor activity using ORR, the clinical benefit rate (CBR) and progression free survival (PFS)
  • Time to first tumor response
  • Residual ER availability with positron emission tomography (PET) scan [(18)F] fluoroestradiol (18F-FES) uptake with increasing doses of amcenestrant
  • Food effect on PK of amcenestrant
  • Potential induction/inhibition effect of amcenestrant on cytochrome P450 (CYP) 3A using 4b-OH cholesterol

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Detailed Description

Duration of the study, per participant, will include eligibility period (screening period) of up to 4 weeks (28 days), treatment period (at least 1 cycle [28 days] of study treatment), and end of treatment (EOT) visit at least 22 to 30 days (or until the participant receives another anticancer therapy, whichever is earlier) following the last study treatment administration. The expected enrollment period is approximately 60 months.

Study Type

Interventional

Enrollment (Actual)

136

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Leuven, Belgium, 3000
        • Investigational Site Number : 0560001
    • Alberta
      • Edmonton, Alberta, Canada, T6G 1Z2
        • Investigational Site Number : 1240004
    • British Columbia
      • Vancouver, British Columbia, Canada, V5Z 1L3
        • Investigational Site Number : 1240003
    • Ontario
      • Toronto, Ontario, Canada, M4N 3M5
        • Investigational Site Number : 1240002
      • Brno, Czechia, 656 53
        • Investigational Site Number : 2030002
      • Prague, Czechia, 128 08
        • Investigational Site Number : 2030001
      • Prague, Czechia, 140 59
        • Investigational Site Number : 2030003
      • Bordeaux, France, 33076
        • Investigational Site Number : 2500002
      • Lille, France, 59000
        • Investigational Site Number : 2500005
      • Lyon, France, 69373
        • Investigational Site Number : 2500003
      • Saint-Herblain, France, 44805
        • Investigational Site Number : 2500001
      • Villejuif, France, 94805
        • Investigational Site Number : 2500004
    • Milano
      • Milan, Milano, Italy, 20141
        • Investigational Site Number : 3800003
    • Pomeranian Voivodeship
      • Gdynia, Pomeranian Voivodeship, Poland, 81-519
        • Investigational Site Number : 6160004
      • Lisbon, Portugal, 1649-035
        • Investigational Site Number : 6200001
      • Lisbon, Portugal, 1998-018
        • Investigational Site Number : 6200002
      • Madrid, Spain, 28041
        • Investigational Site Number : 7240001
      • Madrid, Spain, 28050
        • Investigational Site Number : 7240002
      • Madrid, Spain, 28034
        • Investigational Site Number : 7240007
    • Cardiff [Caerdydd Gb-crd]
      • Cardiff, Cardiff [Caerdydd Gb-crd], United Kingdom, CF14 2TL
        • Investigational Site Number : 8260002
    • Oxfordshire
      • Oxford, Oxfordshire, United Kingdom, OX3 7LE
        • Investigational Site Number : 8260003
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado - Anschutz Medical Campus- Site Number : 8400005
    • Massachusetts
      • Boston, Massachusetts, United States, 02114
        • Massachusetts General Hospital- Site Number : 8400002
    • New York
      • New York, New York, United States, 10065
        • Memorial Sloan Kettering Cancer Center - New York - York Avenue- Site Number : 8400003
    • Washington
      • Seattle, Washington, United States, 98109
        • Fred Hutchinson Cancer Center- Site Number : 8400001

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Participants must be postmenopausal women
  • Histological diagnosis of breast adenocarcinoma
  • Locally advanced or metastatic disease
  • Either primary tumor or any metastatic site to be positive for Estrogen Receptors (ER+) and negative for HER2 (HER2-) receptor
  • Participants must have been previously treated with at least 6 months of endocrine therapy for advanced disease:
  • Dose Escalation study parts:

Arm #3 - Part F and Arm #5 - Part J: up to 2 prior lines of either single endocrine therapy and/or endocrine-based therapy Arm #4 -H: up to 2 prior lines of either single endocrine therapy and/or endocrine-based therapy (exemestane not allowed)

- Dose Expansion study parts: Arm #2: - Part D: no more than 2 prior lines of advanced endocrine therapy for advanced disease are allowed Arm #3, - Part G: patients must have received and progressed on the combination of Aromatase Inhibitors (AI) + CDK4/6 inhibitor as the first line (1L) treatment for advanced disease Arm #4 - Part I: participants must have received and progressed on the combination of Aromatase Inhibitors (AI) +CDK4/6 Inhibitor as the first line (1L) treatment for advanced disease (exemestane not allowed) Arm#5: - Part K: up to 1 prior line of a single endocrine therapy for advanced disease Note: Additional patients who relapsed while on previous adjuvant endocrine therapy that was initiated ≥24 months ago, or relapsed < 12 months after completion of adjuvant endocrine therapy are also allowed for Arms #2, #3, #4, and #5 (Parts C, D, F, G, H, I, J and K).

  • Participants previously treated with chemotherapy for advanced disease: no more than 3 prior chemotherapeutic regimens in Arm #1 Part A, and no more than 1 prior chemotherapeutic regimen in Arms #1, #2, #3, #4, and #5 (Parts B, C, D, F, H and J respectively); prior chemotherapy for advanced disease is not allowed in dose expansion of Arms #3, #4, and #5 (Part G, I and K respectively).
  • Measurable lesion

Exclusion criteria:

  • Medical history or ongoing gastrointestinal disorders that could affect absorption of oral study drugs (including difficulties with swallowing capsules)
  • Participants with any other cancer (except for adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer or any other cancer from which the participant has been disease free for >3 years)
  • Participants with known brain metastases
  • Treatment with anticancer agents (including investigational drugs) less than 2 weeks before first study treatment starts (less than 4 weeks if the anticancer agents were antibodies)
  • Prior treatment with another selective ER down-regulator (SERD)
  • Dose Escalation study parts (Parts F, H and J): SERDs are not allowed except for fulvestrant which will need a washout of at least 6 weeks prior to the first study drug administration
  • Dose Expansion study parts (Parts G, I and K): prior (last) treatment with any SERD including fulvestrant will not be allowed
  • Inadequate hematological and biochemical lab tests
  • Participants with Gilbert disease
  • Treatment with HIV-antiviral, antifungal and antioxidant agents less than 2 weeks before study treatment starts
  • Treatment with strong P450 (CYP) 3A inducers within 2 weeks before first study treatment
  • Treatment with OATP1B1/B3 sensitive substrates and which cannot be replaced
  • Arm#2 Treatment with strong CYP3A inhibitors within 2 weeks before first study treatment starts
  • More than one prior advanced cyclin-dependent kinase (CDK) 4/6 inhibitor-based therapy in Arm #1, Arm #2 (Part C), Arm #3 (Parts F and G), and Arm#4 (Part H).
  • Arm #2, #3, #4 and #5 (Parts C, D, F, G, H, I, J and K) only: participants with concurrent or history of pneumonitis
  • Arm #3, #4 and #5 (Parts F, G, H, I, J and K) only: prior treatment therapies that target the PI3K axis (mTOR inhibitors, AKT inhibitors, PI3K inhibitors)
  • Arm #3 and #4 (Parts F, G, H and I) only: participants with diabetes mellitus type-I or uncontrolled diabetes mellitus type-II: ie, fasting plasma glucose ≥ 140mg/dl (7.7 mmol/l) or HbA1C > 6.2%
  • Arm #3 and #4 (Parts F, G, H and I) only: history of severe cutaneous reaction (eg. Stevens-Johnson syndrome [SJS], erythema multiforme [EM]), toxic epidermal necrolysis (TEN), and drug reaction with eosinophilia and systemic symptoms [DRESS].
  • Arm #3 (Parts F and G) only: ongoing osteonecrosis of jaw
  • Arm #4 (Parts H and I) only: any active, untreated or uncontrolled infection (e.g. viral, bacterial, fungal etc.)
  • Arm #4 (Parts H and I) only: participants with active and uncontrolled stomatitis, angioedema due to concomitant treatment with ACE inhibitors, impaired wounds
  • Arm #4 (Parts H and I) only: uncontrolled hypercholesterolemia, hypertriglyceridemia and hyperglycemia in non-diabetic participants
  • Arm #4 (Parts H and I) only: treatment with strong or moderate CYP3A4 inhibitors, strong CYP3A4 inducers and/or P-gp inhibitors within 2 weeks before the first study treatment administration or 5 elimination half-lives, whichever is the longest
  • Arm #5 (Parts J and K) only: history or current (controlled/not controlled) venous thromboembolism (i.e. deep vein thrombosis (DVT), pulmonary embolism (PE), cerebral venous sinus thrombosis (CVST)

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Amcenestrant Monotherapy: Arm #1 Part A Dose Escalation, Part B Dose Expansion

Part A: Amcenestrant will be administered orally once daily (QD). Treatment will begin with an identified starting dose. Administration of higher doses to subsequent participants is based on occurrence of DLTs and evaluation of target saturation and PK parameters at initial and subsequent doses, until maximum administered dose (MAD) is reached. Drug will be administered in a 28-day cycle.

Part B: When the dose escalation phase ends, the recommended dose will be administered for the expansion cohort. Drug will be administered in a 28-day cycle.

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • SAR439859
Experimental: Amcenestrant/Palbociclib: Arm #2 Part C Dose Escalation, Part D Dose Expansion

Part C: Amcenestrant will be administered in combination with palbociclib: amcenestrant starting oral daily dose will be one dose level below monotherapy RD and palbociclib will be dosed at fixed standard dose. Administration of higher dose of amcenestrant (with standard palbociclib dose) to subsequent participants will be based on occurrence of DLTs at initial and subsequent doses, until MAD of amcenestrant is reached. Drugs will be administered in a 28-day cycle (palbociclib will be administered for 21 days of cycle).

Part D: Based on the results in Part C, participants will be administered either: 1) a determined amcenestrant dose (RD) with standard dose of palbociclib in combination therapy, or 2) one of two randomized dose levels of amcenestrant with standard dose of palbociclib in combination therapy. Drugs will be administered in a 28-day cycle (palbociclib will be administered for 21 days of cycle).

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • SAR439859

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • Ibrance®
Experimental: Amcenestrant/Alpelisib: Arm #3 Part F Safety Run-In, Part G Dose Expansion

Part F: Amcenestrant will be administered in combination with alpelisib at a fixed standard dose. Additional dose levels of amcenestrant with alpelisib could be explored if needed based on the safety and PK results. Lower dose of alpelisib could be explored based on the PK results and safety profile from the initial combination administration. Both amcenestrant and alpelisib will be administered in a 28-day cycle.

Part G: Based on the conclusion in Part F, participants will be administered the determined RD of amcenestrant and alpelisib given in the combination in an expansion cohort. Both study drugs will be administered in a 28-day cycle.

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • SAR439859

Pharmaceutical form: tablet

Route of administration: oral

Other Names:
  • Piqray®
Experimental: Amcenestrant/Everolimus: Arm #4 Part H Dose Escalation, Part I Dose Expansion

Part H: Amcenestrant will be administered at the determined RD in combination with 2 dose levels of everolimus. Additional dose levels of amcenestrant with everolimus could be explored if needed based on the safety and PK results. Both amcenestrant and everolimus will be administered in a 28-day cycle.

Part I: Based on the conclusion in Part H, participants will be administered the determined RD of amcenestrant and RD of everolimus given in the combination in an expansion cohort. Both study drugs will be administered in a 28-day cycle.

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • SAR439859
Pharmaceutical form: tablet
Experimental: Amcenestrant/Abemaciclib: Arm #5 Part J Dose Escalation, Part K Dose Expansion

Part J: Amcenestrant will be administered at the determined RD in combination with 2 dose levels of abemaciclib. Additional dose levels of amcenestrant with abemaciclib could be explored if needed based on the safety and PK results. Both amcenestrant and abemaciclib will be administered in a 28-day cycle.

Part K: Based on the conclusion in Part J, participants will be administered the determined RD of amcenestrant and RD of abemaciclib given in the combination in an expansion cohort. Both study drugs will be administered in a 28-day cycle.

Pharmaceutical form: capsule

Route of administration: oral

Other Names:
  • SAR439859
Pharmaceutical form: tablet
Other Names:
  • Verzenio®

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Parts A, C, F, H, J: Number of Participants With Study Treatment-Related Dose-Limiting Toxicities (DLTs)
Time Frame: Cycle 1 Day 1 to Cycle 1 Day 28 (cycle duration=28 days)
DLTs: any treatment-emergent adverse event(TEAE) related to study treatment per National Cancer Institute Common Terminology Criteria for AE scale version (v) 4.03:Grade(G)≥3 nonhematological toxicity except:G3 nausea/vomiting resolved to G≤1 in 48 hours(h),G3 diarrhea with therapy and lasting<48h,G3 hyperglycemia resolved to G≤1 in 48h(Part H);G≥3 hematological toxicity except:G3 anemia,G4 neutropenia<7days(d),G3 neutropenia without fever/infection,G3 thrombocytopenia without bleeding;elevated total serum bilirubin(BL)>2xupper limit of normal(except Part F),Part F:G3 hyperglycemia not resolved to G≤2 in 7d after antidiabetic treatment,G2 hyperglycemia not resolved to G≤1 in 21d,G2 alanine aminotransferase(ALT) increase in conjunction with total blood BL G≥2 without liver metastases,G≥3 ALT/aspartate aminotransferase increase for>4d,G3 rash/maculopapular rash not resolved to G≤1 in 7d;treatment related toxicity causing≥7d omission in Cycle 1 or >2 weeks delay in Cycle 2 in Part C.
Cycle 1 Day 1 to Cycle 1 Day 28 (cycle duration=28 days)
Part B: Objective Response Rate (ORR) as Determined by Independent Central Review (ICR)
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
ORR was determined by dividing the number of participants who achieved confirmed complete response (CR) or partial response (PR) by the number of participants from the analysis population. ORR was assessed by ICR according to response evaluation criteria in solid tumors (RECIST) v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 millimeters (mm). PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
Parts D, I: Number of Participants With Treatment-Emergent Adverse Events and Treatment-Emergent Serious Adverse Events (TESAEs)
Time Frame: From first dose of study treatment administration (Day 1) up to 30 days after the last dose of study treatment administration; approximately 232 weeks for Part D and 11 weeks for Part I
AE was any untoward medical occurrence in a participant or clinical investigation participant administered with a pharmaceutical product and which did not necessarily had a causal relationship with the treatment. SAE was any untoward medical occurrence that at any dose, resulted in death, was life-threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was a medically important event. TEAEs were AEs that developed or worsened or became serious during the treatment period.
From first dose of study treatment administration (Day 1) up to 30 days after the last dose of study treatment administration; approximately 232 weeks for Part D and 11 weeks for Part I

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Parts A, B, C, F, H, J: Number of Participants With Treatment-Emergent Adverse Events and Treatment-Emergent Serious Adverse Events
Time Frame: From first dose of study treatment administration (Day 1) up to 30 days after the last dose of study treatment administration; approximately 94, 282, 144, 96, 59, 130 weeks for Parts A, B, C, F, H, J respectively
AE was any untoward medical occurrence in a participant or clinical investigation participant administered with a pharmaceutical product and which did not necessarily had a causal relationship with the treatment. SAE was any untoward medical occurrence that at any dose, resulted in death, was life-threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, or was a medically important event. TEAEs were AEs that developed or worsened or became serious during the treatment period.
From first dose of study treatment administration (Day 1) up to 30 days after the last dose of study treatment administration; approximately 94, 282, 144, 96, 59, 130 weeks for Parts A, B, C, F, H, J respectively
Parts A, B, C, D, F, H, I, J: Objective Response Rate as Determined by Investigators/Local Radiologists
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
ORR was determined by dividing the number of participants who achieved confirmed CR or PR by the number of participants from the analysis population. ORR was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
Parts A, B, C, D, F, H, I, J: Clinical Benefit Rate (CBR) as Determined by Investigators/Local Radiologists
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
CBR was determined by dividing the number of participants who achieved confirmed CR, PR as best overall response (BOR) or stable disease (SD) for ≥24 weeks by the number of participants from the analysis population. CBR was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. SD was defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD), taking as reference the smallest sum diameters while on study.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
Part B: Clinical Benefit Rate as Determined by Independent Central Review
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
CBR was determined by dividing the number of participants who achieved confirmed CR, PR as BOR or SD for ≥24 weeks by the number of participants from the analysis population. CBR was assessed by ICR according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. SD was defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum diameters while on study.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
Parts A, B, C, D, F, H, I, J: Duration of Response (DOR) as Determined by Investigators/Local Radiologists
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
DOR was defined as the time interval from the date of the first occurrence of confirmed CR or PR to the date of the first documentation of disease progression or death due to disease progression, whichever occurred first. DOR was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. PD was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, an absolute increase of at least 5 mm in the sum. Appearance of 1 or more new lesions was also considered progression.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
Part B: Duration of Response as Determined by Independent Central Review
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
DOR was defined as the time interval from the date of the first occurrence of confirmed CR or PR to the date of the first documentation of disease progression or death due to disease progression, whichever occurred first. DOR was assessed by ICR according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. PD was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, an absolute increase of at least 5 mm in the sum. Appearance of 1 or more new lesions was also considered progression.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
Parts A, B, C, D, F, H, I, J: Progression-Free Survival (PFS) as Determined by Investigators/Local Radiologists
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
PFS was defined as time from the date of the first treatment intake to the date of the first documentation of objective PD according to RECIST v1.1, clinical PD or death due to any cause, whichever occurred first. PFS was assessed by investigators/local radiologists. PD was defined as at least a 20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study, an absolute increase of at least 5 mm in the sum. Appearance of 1 or more new lesions was also considered progression.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
Parts A, B, C, D: Objective Response Rate as Determined by Investigators/Local Radiologists According to Estrogen Receptor 1 (ESR1) Mutation at Baseline
Time Frame: From Baseline (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228 weeks for Parts A, B, C, D respectively
ORR was determined by dividing the number of participants who achieved confirmed CR or PR by the number of participants from the analysis population. ORR was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. The ESR1 gene mutation status (mutated or wild-type) was analyzed by multiplex droplet digital polymerase chain reaction (ddPCR) after extraction of plasma circulating deoxyribonucleic acid (DNA). The baseline value was defined as the last value or measurement taken up to the date and time of the first dose of study treatment irrespective of the treatment.
From Baseline (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228 weeks for Parts A, B, C, D respectively
Part B: Objective Response Rate as Determined by Independent Central Review According to Estrogen Receptor 1 Mutation at Baseline
Time Frame: Baseline (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
ORR was determined by dividing the number of participants who achieved confirmed CR or PR by the number of participants from the analysis population. ORR was assessed by ICR according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. The ESR1 gene mutation status (mutated or wild-type) was analyzed by multiplex ddPCR after extraction of plasma circulating DNA. The baseline value was defined as the last value or measurement taken up to the date and time of the first dose of study treatment irrespective of the treatment.
Baseline (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
Parts A, B, C, D: Clinical Benefit Rate as Determined by Investigators/Local Radiologists According to Estrogen Receptor 1 Mutation at Baseline
Time Frame: From Baseline (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228 weeks for Parts A, B, C, D respectively
CBR was determined by dividing the number of participants who achieved confirmed CR, PR as BOR or SD for ≥24 weeks by the number of participants from analysis population. CBR was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters. SD was defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for PD, taking as reference the smallest sum diameters while on study. The ESR1 gene mutation status (mutated or wild-type) was analyzed by multiplex ddPCR after extraction of plasma circulating DNA. Baseline value was defined as the last value or measurement taken up to the date and time of the first dose of study treatment irrespective of the treatment.
From Baseline (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228 weeks for Parts A, B, C, D respectively
Parts B, D, I: Time to First Confirmed Response as Determined by Investigators/Local Radiologists
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
The time to first confirmed response was defined as the time interval from the date of first administration of the study treatment to the date of the first occurrence of confirmed CR or PR. The time to first confirmed response was assessed by investigators/local radiologists according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 90, 278, 140, 228, 92, 55, 7, 126 weeks for Parts A, B, C, D, F, H, I, J respectively
Part B: Time to First Confirmed Response as Determined by Independent Central Review
Time Frame: From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
The time to first confirmed response was defined as the time interval from the date of first administration of the study treatment to the date of the first occurrence of confirmed CR or PR. The time to first confirmed response was assessed by ICR according to RECIST v1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) had a reduction in short axis to <10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.
From first dose of study treatment administration (Day 1) up to maximum exposure of study treatment; approximately 278 weeks
Part A: Number of Participants With 18F-Fluorestradiol Positron Emission Tomography Percentage Reduction
Time Frame: Baseline (within 3 days or more prior to Day 1) and between Day 11 and Day 15 of Cycle 1 (cycle duration=28 days)
Inhibition of estrogen receptor (ER) occupancy investigation using 18F-FES-PET imaging was a limited invasive procedure that allowed assessment of ER presence by assessing the binding of radiolabeled estradiol, the ligand of ER (signal extinction). Number of participants with percentage reduction (≥90%, ≥70%, ≥50% and ≥30%) in 18F-FES-PET signal are reported. The baseline value was defined as the last value or measurement taken up to the date and time of the first dose of study treatment irrespective of the treatment.
Baseline (within 3 days or more prior to Day 1) and between Day 11 and Day 15 of Cycle 1 (cycle duration=28 days)
Parts A, B, C, D, H, I, J: Time Interval Between Administration and the Sampling Preceding the First Concentration Above the Lower Limit of Quantification (LLOQ) (Tlag) of Amcenestrant After a Single Oral Administration
Time Frame: Cycle 1 Day 1 (cycle duration=28 days)
Blood samples were collected at the specified timepoint for the measurement of amcenestrant concentrations. Pharmacokinetic (PK) parameters were determined by non-compartmental analysis. LLOQ value for amcenestrant was 5 nanograms per milliliter (ng/mL).
Cycle 1 Day 1 (cycle duration=28 days)
Parts A, B, C, D, H, I, J: Time to Reach Maximum Plasma Concentration (Tmax) of Amcenestrant After a Single Oral Administration
Time Frame: Cycle 1 Day 1 (cycle duration=28 days)
Blood samples were collected at the specified timepoint for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis.
Cycle 1 Day 1 (cycle duration=28 days)
Parts A, B, C, D, H, I, J: Maximum Plasma Concentration (Cmax) of Amcenestrant After a Single Oral Administration
Time Frame: Cycle 1 Day 1 (cycle duration=28 days)
Blood samples were collected at the specified timepoint for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis.
Cycle 1 Day 1 (cycle duration=28 days)
Parts A, B, C, D, H, I, J: Area Under the Plasma Concentration Versus Time Curve From Time Zero to Dosing Interval (AUC0-tau) of Amcenestrant After a Single Oral Administration
Time Frame: Cycle 1 Day 1 (cycle duration=28 days)
Blood samples were collected at the specified timepoint for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis. tau=12 h for Part A BID dosing and 24 h for other parts.
Cycle 1 Day 1 (cycle duration=28 days)
Parts A, B, C, D, F, H, I, J: Time to Reach Maximum Plasma Concentration of Amcenestrant After Repeated Oral Administrations
Time Frame: Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Blood samples were collected at the specified timepoints for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis.
Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Parts A, B, C, D, F, H, I, J: Maximum Plasma Concentration of Amcenestrant After Repeated Oral Administrations
Time Frame: Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Blood samples were collected at the specified timepoints for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis.
Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Parts A, B, C, D, F, H, I, J: Area Under the Plasma Concentration Versus Time Curve From Time Zero to Dosing Interval of Amcenestrant After Repeated Oral Administrations
Time Frame: Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Blood samples were collected at the specified timepoints for the measurement of amcenestrant concentrations. PK parameters were determined by non-compartmental analysis. tau=12 h for Part A BID dosing and 24 h for other parts.
Parts A, B, F, H, I, J: Cycle 1 Day 22; Parts C and D: Cycle 1 Day 21 (cycle duration=28 days)
Parts A, B, C, D, F, H, I, J: Plasma Concentration Observed Before Treatment Administration (Ctrough) of Amcenestrant
Time Frame: Cycle 1: Pre-dose (0 hour) on Day 8 (Parts A, B, C, D), Day 15 (Parts B, C, D), Day 21 (Parts C and D) and Day 22 (Parts A, B, F, H, I, J) (cycle duration=28 days)
Blood samples were collected at the specified timepoints for the measurement of amcenestrant concentrations.
Cycle 1: Pre-dose (0 hour) on Day 8 (Parts A, B, C, D), Day 15 (Parts B, C, D), Day 21 (Parts C and D) and Day 22 (Parts A, B, F, H, I, J) (cycle duration=28 days)
Part B: Cumulated Amount of Amcenestrant Excreted in Urine From Time 0 to 24 Hours (Ae0-24)
Time Frame: Day 22 of Cycle 1 (cycle duration=28 days)
Urine samples were collected at the specified timepoints for the measurement of amcenestrant amount excreted in urine.
Day 22 of Cycle 1 (cycle duration=28 days)
Part A (QD Regimen): Geometric Mean Ratio of Area Under the Plasma Concentration Versus Time Curve From Time Zero to 24 Hours (AUC0-24) of Amcenestrant
Time Frame: Days 1 and 3 of Cycle 1 (cycle duration=28 days)
The food effect was assessed by comparing the geometric means of AUC0-24 between Cycle 1 Day 1 (fasted condition) and Cycle 1 Day 3 (fed condition) in Part A.
Days 1 and 3 of Cycle 1 (cycle duration=28 days)
Part A (QD Regimen): Geometric Mean Ratio of Maximum Plasma Concentration of Amcenestrant
Time Frame: Days 1 and 3 of Cycle 1 (cycle duration=28 days)
The food effect was assessed by comparing the geometric means of Cmax between Cycle 1 Day 1 (fasted condition) and Cycle 1 Day 3 (fed condition) in Part A.
Days 1 and 3 of Cycle 1 (cycle duration=28 days)
Parts C and D: Time to Reach Maximum Plasma Concentration of Palbociclib After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 21) of palbociclib in combination with amcenestrant for the measurement of palbociclib concentrations. PK parameters were determined by non-compartmental analysis.
Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Parts C and D: Maximum Plasma Concentration of Palbociclib After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 21) of palbociclib in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Parts C and D: Area Under the Plasma Concentration Versus Time Curve From Time Zero to 24 Hours of Palbociclib After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 21) of palbociclib in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 21 of Cycle 1 (cycle duration=28 days)
Part F: Time to Reach Maximum Plasma Concentration of Alpelisib After Repeated Oral Administrations Alone or in Combination With Amcenestrant
Time Frame: Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after 3-day repeated oral administrations of alpelisib as monotherapy (Day 3) and after 22-day repeated oral administrations of alpelisib in combination with repeated doses of amcenestrant (Day 22). PK parameters were determined by non-compartmental analysis.
Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Part F: Maximum Plasma Concentration of Alpelisib After Repeated Oral Administrations Alone or in Combination With Amcenestrant
Time Frame: Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after 3-day repeated oral administrations of alpelisib as monotherapy (Day 3) and after 22-day repeated oral administrations of alpelisib in combination with repeated doses of amcenestrant (Day 22). PK parameters were determined by non-compartmental analysis.
Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Part F: Area Under the Plasma Concentration Versus Time Curve From Time Zero to 24 Hours of Alpelisib After Repeated Oral Administrations Alone or in Combination With Amcenestrant
Time Frame: Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after 3-day repeated oral administrations of alpelisib as monotherapy (Day 3) and after 22-day repeated oral administrations of alpelisib in combination with repeated doses of amcenestrant (Day 22). PK parameters were determined by non-compartmental analysis.
Days 3 and 22 of Cycle 1 (cycle duration=28 days)
Parts H and I: Time to Reach Maximum Plasma Concentration of Everolimus After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of everolimus in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Parts H and I: Maximum Plasma Concentration of Everolimus After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of everolimus in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Parts H and I: Area Under the Plasma Concentration Versus Time Curve From Time Zero to 24 Hours of Everolimus After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of everolimus in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Part J: Time to Reach Maximum Plasma Concentration of Abemaciclib and Its Metabolites M2, M18 and M20 After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of abemaciclib in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Part J: Maximum Plasma Concentration of Abemaciclib and Its Metabolites M2, M18 and M20 After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of abemaciclib in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Part J: Area Under the Plasma Concentration Versus Time Curve From Time Zero to 12 Hours of Abemaciclib and Its Metabolites M2, M18 and M20 After First Dose and Repeated Oral Administrations in Combination With Amcenestrant
Time Frame: Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Blood samples were collected after single dose (Day 1) and repeated oral administrations (Day 22) of abemaciclib in combination with amcenestrant. PK parameters were determined by non-compartmental analysis.
Days 1 and 22 of Cycle 1 (cycle duration=28 days)
Parts A, B, J: Post/Pre--Treatment Ratio of 4 Beta (β)-Hydroxycholesterol
Time Frame: Pre-treatment on Day 1 of Cycle 1; post-treatment on Day 22 of Cycle 1, Day 1 and Day 28 (only for Part J) of Cycle 2 (cycle duration=28 days)
Ratios of 4β-hydroxycholesterol concentrations were calculated from plasma samples collected before and after amcenestrant administration.
Pre-treatment on Day 1 of Cycle 1; post-treatment on Day 22 of Cycle 1, Day 1 and Day 28 (only for Part J) of Cycle 2 (cycle duration=28 days)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Study Director: Clinical Sciences & Operations, Sanofi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 20, 2017

Primary Completion (Actual)

November 8, 2024

Study Completion (Actual)

November 8, 2024

Study Registration Dates

First Submitted

September 13, 2017

First Submitted That Met QC Criteria

September 13, 2017

First Posted (Actual)

September 15, 2017

Study Record Updates

Last Update Posted (Actual)

November 24, 2025

Last Update Submitted That Met QC Criteria

November 6, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Other Study ID Numbers

  • TED14856
  • 2017-000690-36 (EudraCT Number)
  • U1111-1189-4896 (Registry Identifier: ICTRP)
  • 2024-512997-89 (Registry Identifier: CTIS)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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