# Study of Amcenestrant (SAR439859) Versus Tamoxifen for Patients With Hormone Receptor-positive (HR+) Early Breast Cancer, Who Have Discontinued Adjuvant Aromatase Inhibitor Therapy Due to Treatment-related Toxicity

> **NCT05128773** · PHASE3 · TERMINATED · sponsor: **Sanofi** · enrollment: 3 (actual)

## Conditions studied

- Breast Cancer

## Interventions

- **DRUG:** Amcenestrant
- **DRUG:** Tamoxifen
- **DRUG:** Amcenestrant-matching placebo
- **DRUG:** Tamoxifen-matching placebo

## Key facts

- **NCT ID:** NCT05128773
- **Lead sponsor:** Sanofi
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE3
- **Study type:** INTERVENTIONAL
- **Status:** TERMINATED
- **Start date:** 2022-02-17
- **Primary completion:** 2022-10-13
- **Final completion:** 2022-10-13
- **Target enrollment:** 3 (ACTUAL)
- **Why stopped:** Sponsor decision to prematurely stop the study, not linked to any safety concern
- **Last updated:** 2025-09-16

## Collaborators

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- [object Object]

## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05128773

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05128773, "Study of Amcenestrant (SAR439859) Versus Tamoxifen for Patients With Hormone Receptor-positive (HR+) Early Breast Cancer, Who Have Discontinued Adjuvant Aromatase Inhibitor Therapy Due to Treatment-related Toxicity". Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/clinical/NCT05128773. Licensed CC0.

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