# Palazestrant combination study

Source: https://onco.cc/trials/nct05508906/  
OnCo record `nct05508906` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

This early study tests palazestrant with ribociclib, alpelisib, everolimus or atirmociclib. It seeks suitable combination doses and evaluates side effects and drug levels.

## Summary

This early study tests palazestrant with ribociclib, alpelisib, everolimus or atirmociclib. It seeks suitable combination doses and evaluates side effects and drug levels.

Interventional study registered as NCT05508906, sponsored by Olema Pharmaceuticals, Inc.. Registry phase: 1. Registry enrollment is 190 participants (estimated). Registry status checked October 10, 2026: active not recruiting. UCSF lists this study as closed to local enrollment; local availability and overall registry status are separate. See the registry for full eligibility and current sites.

## Fields

- Kind: Trial
- Status: active
- Last checked: 2026-10-10
- Also known as: Phase 1b Study of OP-1250 (Palazestrant) in Combination With Ribociclib, Alpelisib, Everolimus, or Atirmociclib in ER+, HER2- Breast Cancer
- Tags: ucsf-breast-coverage; interventional
- Registry id: NCT05508906
- Phase: 1
- Setting: Estrogen receptor-positive, HER2-negative advanced breast cancer
- Sponsor: Olema Pharmaceuticals, Inc.

## Sources

- ClinicalTrials.gov NCT05508906: https://clinicaltrials.gov/study/NCT05508906
- UCSF study listing and local availability: https://clinicaltrials.ucsf.edu/trial/NCT05508906

## Connected records

- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/)
- drugs: [Alpelisib](https://onco.cc/drugs/alpelisib/), [Atirmociclib](https://onco.cc/drugs/atirmociclib/), [Everolimus](https://onco.cc/drugs/everolimus/), [Ribociclib](https://onco.cc/drugs/ribociclib/)
- institutions: [UCSF Helen Diller Family Comprehensive Cancer Center](https://onco.cc/institutions/ucsf/)

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JSON: https://onco.cc/api/v1/entities/nct05508906.json