# Preoperative Window Opportunity Study With Giredestrant or Tamoxifen in Premenopausal Women With ER+/HER2[-] & Ki67≥10%

> **NCT05659563** · PHASE2 · COMPLETED · sponsor: **MedSIR** · enrollment: 92 (actual)

## Conditions studied

- Breast Cancer
- Breast Cancer, Early-Onset

## Interventions

- **DRUG:** Giredestrant
- **DRUG:** Tamoxifen

## Key facts

- **NCT ID:** NCT05659563
- **Lead sponsor:** MedSIR
- **Sponsor class:** OTHER
- **Phase:** PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** COMPLETED
- **Start date:** 2023-07-20
- **Primary completion:** 2025-01-30
- **Final completion:** 2025-01-30
- **Target enrollment:** 92 (ACTUAL)
- **Last updated:** 2026-03-19


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05659563

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05659563, "Preoperative Window Opportunity Study With Giredestrant or Tamoxifen in Premenopausal Women With ER+/HER2[-] & Ki67≥10%". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT05659563. Licensed CC0.

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