OncoMatch

OncoMatch/Clinical Trials/NCT05900895

Estradiol Plus Olaparib for Breast Cancer (PHOEBE)

Is NCT05900895 recruiting? Yes, currently enrolling (May 2026). This Phase 1 trial studies multiple treatments including Olaparib and 17b-estradiol for metastatic breast cancer.

Phase 1RecruitingMary D ChamberlinNCT05900895Data as of May 2026

Treatment: Olaparib · 17b-estradiolDetermine the safety and recommended Phase II dose of olaparib in combination with 17b-estradiol in post-menopausal patients with advanced ER+/HER2- breast cancer.

Check if I qualify

Extracted eligibility criteria

Cancer type

Breast Carcinoma

Biomarker criteria

Required: ESR1 overexpression (ER+)

ER+

Required: HER2 (ERBB2) wild-type (HER2-)

HER2-

Disease stage

Metastatic disease required

Prior therapy

Min 1 prior line

Must have received: endocrine-based therapy — advanced/metastatic

Received ≥1 prior line of endocrine-based therapy in the advanced/metastatic setting

Cannot have received: systemic chemotherapy

Exception: within the last 3 weeks

Any investigational cancer therapy or systemic chemotherapy in the last 3 weeks

Cannot have received: radiation therapy

Exception: within the last 2 weeks

Any radiation therapy in the last 2 weeks

Lab requirements

Kidney function

creatinine clearance > 30 ml/min

Structured fields extracted by AI. May contain errors — verify against the official protocol.

US trial sites

  • Dartmouth Cancer Center · Lebanon, New Hampshire

Showing up to 5 US sites. See all sites on ClinicalTrials.gov →

Could you qualify for this trial?

Enter your biomarker results to see how this trial's eligibility criteria match your specific cancer profile.

Check if I qualify