# A Study of Letrozole, Palbociclib, and Onapristone ER in People With Metastatic Breast Cancer

> **NCT04872608** · PHASE1 · WITHDRAWN · sponsor: **Memorial Sloan Kettering Cancer Center**

## Conditions studied

- Metastatic Breast Cancer
- Unresectable Breast Cancer

## Interventions

- **DRUG:** Letrozole
- **DRUG:** Palbociclib
- **DRUG:** Onapristone ER

## Key facts

- **NCT ID:** NCT04872608
- **Lead sponsor:** Memorial Sloan Kettering Cancer Center
- **Sponsor class:** OTHER
- **Phase:** PHASE1
- **Study type:** INTERVENTIONAL
- **Status:** WITHDRAWN
- **Start date:** 2021-09-09
- **Primary completion:** 2023-04-25
- **Final completion:** 2023-04-25
- **Target enrollment:** 0 (ACTUAL)
- **Why stopped:** The sponsor closed the study due to discontinuing their onapristone program
- **Last updated:** 2023-04-28

## Collaborators

- [object Object]

## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT04872608

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT04872608, "A Study of Letrozole, Palbociclib, and Onapristone ER in People With Metastatic Breast Cancer". Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/clinical/NCT04872608. Licensed CC0.

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*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*