Phase 2 Window Study of SAR439859 (Amcenestrant) Versus Letrozole in Post-menopausal Patients With ER+, HER2- Pre-operative Post-menopausal Primary Breast Cancer

What this trial studies

Primary Objective: To determine whether amcenestrant given at 2 different doses improved the antiproliferative activity when compared to letrozole. Secondary Objectives: * To assess the proportion of participants with a relative decrease from Baseline in percentage of positive tumor cells tested by immunohistochemistry greater than or equal to (\>=) 50 percent (%) (Ki67 \>=50%) in the three treatment arms. * To assess estrogen receptor (ER) degradation in biopsies in participants in the three treatment arms. * To assess safety in the three treatment arms.

Conditions in scope

• Breast Cancer

Interventions

• Amcenestrant (SAR439859) (Drug) — Pharmaceutical form: Capsules, Route of administration: Oral
• Letrozole (Drug) — Pharmaceutical form: Tablets, Route of administration: Oral

Who can join

Women only · Ages 18 Years and up

Inclusion criteria

• Histological or cytological proven diagnosis of invasive breast adenocarcinoma.
• Localized breast cancer eligible for upfront breast conservative surgery or upfront mastectomy: Stage I, Stage II or operable Stage III (excluded T4) as defined in American Joint Committee on Cancer (AJCC) Cancer Staging Manual 8th edition 2017.
• Postmenopausal women as defined by one of the following:
• Spontaneous cessation of menses greater than (\>) 12 months.
• or who had received hormonal replacement therapy but had discontinued the treatment and had follicle stimulating hormone (FSH) level in the postmenopausal range.
• or with status post bilateral surgical oophorectomy.
• or post bilateral ovarian ablation through pelvic radiotherapy.
• Breast tumor size of at least 10 millimeters (mm) in greatest dimension measured by ultrasound.

Exclusion criteria

• Medical history or ongoing gastrointestinal disorders potentially affecting the absorption of SAR439859 or letrozole.
• Participants unable to swallow normally and to take capsules or tablets.
• Participants with known active hepatitis A, B, C infection; or hepatic cirrhosis.
• Participant with any other cancer; adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer or any other cancer from which the participant had been disease free for \>3 years were allowed.
• Evidence of metastatic spread by standard assessment according to local practice.
• Treatment with strong Cytochrome P450 3A (CYP3A) inducers or drugs that had the potential to inhibit uridine diphosphate glucuronosyltransferase (UGT) within 2 weeks before first study treatment administration or 5 elimination half-lives whichever was longest.
• Treatment with drugs that were sensitive substrates of P-glycoprotein (P-gp) or of breast cancer resistance protein (BCRP) within 2 weeks before first study treatment administration or 5 elimination half-lives whichever was longer.
• Use of any investigational agent within 4 weeks prior to randomization.

Eligibility wording paraphrased from the public record. View the full criteria on ClinicalTrials.gov before contacting a site.

Where it’s happening

Showing the first 10 of 32 sites. See all sites on ClinicalTrials.gov.

Status & timeline

• Overall status: Terminated
• Study type: Interventional
• Phase: PHASE2
• Start date: 2020-02-04
• Primary completion: 2021-04-30
• Last update posted: 2025-09-18
• First posted: 2019-12-09

Sponsor & contact

Lead sponsor: Sanofi (Industry)

For trial site contact information, use the official record at ClinicalTrials.gov. Contact details change frequently and the public record is the source of truth.

Outcome measures

Primary outcomes

• Percent Change From Baseline in Ki67 Level at Day 15 (Baseline, Day 15)
  Tumor tissue collected through a core-cut biopsy at Baseline and Day 15 was used to determine Ki67 expression. Ki67 expression was defined as the percentage of positive tumor cells assessed by central reading. Ki67 percent change from Baseline for a given participant was defined as 100*(Ki67pre - Ki67post) / Ki67pre, where Ki67pre and Ki67post were pre-treatment and post-treatment Ki67 value…

Related ClearedRx care

If you’re reading this trial because you have menopause symptoms now, you don’t have to wait for a trial to access evidence-based care. ClearedRx prescribes the same FDA-approved and compounded HRT products that have been studied in trials like this one for decades.