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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 (Jun 2026). This Phase 2 trial studies multiple treatments including Belzutifan and Fulvestrant for metastatic breast cancer.

Phase 2RecruitingMerck Sharp & Dohme LLCNCT06428396Data as of Jun 2026Location: International · 9 countries

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

Treatments studied

Targeted therapy

Everolimus

Endocrine / hormonal

FulvestrantExemestane

Other

Belzutifan

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 →

Frequently asked questions

Is NCT06428396 currently recruiting?

Yes, this trial is currently recruiting patients.

Are there prior therapy exclusions?

Yes. Prior fulvestrant, cytotoxic chemotherapy, PARP inhibitor disqualifies patients from enrollment.

Does this trial require ESR1?

Yes, ESR1 overexpression is a required biomarker for enrollment.

Does this trial require ERBB2?

Yes, ERBB2 wild-type is a required biomarker for enrollment.

Are patients with BRCA1 alterations eligible?

No. BRCA1 deleterious or suspected deleterious germline mutation is an exclusion criterion.

Are patients with BRCA2 alterations eligible?

No. BRCA2 deleterious or suspected deleterious germline mutation is an exclusion criterion.

Could you qualify for this trial?

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

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