# Phase 1b Study of OP-1250 (Palazestrant) in Combination With Ribociclib, Alpelisib, Everolimus, or Atirmociclib in ER+, HER2- Breast Cancer

> **NCT05508906** · PHASE1 · RECRUITING · sponsor: **Olema Pharmaceuticals, Inc.** · enrollment: 190 (estimated)

## Conditions studied

- Metastatic Breast Cancer
- ER-positive Breast Cancer
- HER2-negative Breast Cancer
- Breast Cancer
- Locally Advanced Breast Cancer

## Interventions

- **DRUG:** Palazestrant
- **DRUG:** Ribociclib
- **DRUG:** Alpelisib
- **DRUG:** Everolimus
- **DRUG:** Atirmociclib

## Key facts

- **NCT ID:** NCT05508906
- **Lead sponsor:** Olema Pharmaceuticals, Inc.
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE1
- **Study type:** INTERVENTIONAL
- **Status:** RECRUITING
- **Start date:** 2022-08-31
- **Primary completion:** 2027-12-31
- **Final completion:** 2028-01-31
- **Target enrollment:** 190 (ESTIMATED)
- **Last updated:** 2025-10-22

## Collaborators

- [object Object]
- [object Object]

## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05508906

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05508906, "Phase 1b Study of OP-1250 (Palazestrant) in Combination With Ribociclib, Alpelisib, Everolimus, or Atirmociclib in ER+, HER2- Breast Cancer". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT05508906. Licensed CC0.

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