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OncoMatch/Clinical Trials/NCT06428396

Study of Belzutifan (MK-6482) Plus Fulvestrant for ER+/HER2- Metastatic Breast Cancer (MK-6482-029/LITESPARK-029)

Is NCT06428396 recruiting? Yes, currently enrolling (May 2026). This Phase 2 trial studies multiple treatments including Belzutifan and Fulvestrant for metastatic breast cancer.

Phase 2RecruitingMerck Sharp & Dohme LLCNCT06428396Data as of May 2026

Treatment: Belzutifan · Fulvestrant · Everolimus · ExemestaneThe purpose of this study is to assess the efficacy and safety of belzutifan (MK-6482) plus fulvestrant compared to everolimus plus endocrine therapy (ET) (investigator's choice of fulvestrant or exemestane) in adults with estrogen receptor-positive, human epidermal growth factor receptor 2-negative (ER+/HER2-) unresectable metastatic breast cancer. There is no formal hypothesis testing in this study.

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Extracted eligibility criteria

Cancer type

Breast Carcinoma

Biomarker criteria

Required: ESR1 overexpression (positive)

estrogen receptor positive (ER+)

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

human epidermal growth factor receptor negative (HER2-)

Excluded: BRCA1 deleterious or suspected deleterious germline mutation

known germline BRCA mutation (deleterious or suspected deleterious) and has received previous treatment with poly-ADP ribose polymerase (PARP) inhibition

Excluded: BRCA2 deleterious or suspected deleterious germline mutation

known germline BRCA mutation (deleterious or suspected deleterious) and has received previous treatment with poly-ADP ribose polymerase (PARP) inhibition

Performance status

ECOG 0–1(Restricted strenuous activity)

Prior therapy

Must have received: endocrine therapy — noncurative

disease progression during or after the last administered endocrine therapy (ET)

Must have received: CDK4/6 inhibitor — noncurative

Radiographic disease progression on 12 months or more of ET in combination with CDK4/6 inhibitor in the noncurative setting or ... at least 2 lines of ET in the noncurative setting including CDK4/6 inhibitor where the CDK 4/6 inhibitor was discontinued due to intolerance

Cannot have received: fulvestrant (fulvestrant)

Has received prior fulvestrant in the adjuvant, unresectable locally advanced, or metastatic setting

Cannot have received: cytotoxic chemotherapy

Has received any line of cytotoxic chemotherapy ... in the unresectable or noncurative advanced/metastatic setting

Cannot have received: PARP inhibitor

Has received any line of ... PARP inhibitor in the unresectable or noncurative advanced/metastatic setting

Cannot have received: PARP inhibitor

known germline BRCA mutation (deleterious or suspected deleterious) and has received previous treatment with poly-ADP ribose polymerase (PARP) inhibition either in the adjuvant or metastatic setting

Cannot have received: systemic anticancer therapy

Has received prior systemic anticancer therapy including investigational agents within 4 weeks before randomization

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

US trial sites

  • City of Hope - Phoenix ( Site 0006) · Goodyear, Arizona
  • Cedars Sinai Medical Center ( Site 0012) · Beverly Hills, California
  • Moores Cancer Center at UC San Diego Health ( Site 0025) · La Jolla, California
  • USC/Norris Comprehensive Cancer Center ( Site 0013) · Los Angeles, California
  • USC Norris Oncology Hematology Newport Beach ( Site 0029) · Newport Beach, California

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

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