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

NCT ID: NCT06428396

Last Updated: 2025-11-12

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

RECRUITING

Clinical Phase

PHASE2

Total Enrollment

120 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-11-27

Study Completion Date

2028-10-07

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

The 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.

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Metastatic Breast Cancer

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Belzutifan + Fulvestrant

Participants will receive belzutifan 120 mg orally once daily (QD) PLUS fulvestrant 500 mg via intramuscular (IM) injection on Days 1 and 15 of Cycle 1, and Day 1 of each 28-day cycle thereafter until progressive disease or discontinuation.

Group Type EXPERIMENTAL

Belzutifan

Intervention Type DRUG

Belzutifan 120 mg administered QD as an oral tablet.

Fulvestrant

Intervention Type DRUG

Fulvestrant 500 mg administered as an IM injection.

Everolimus + ET (fulvestrant or exemestane)

Participants will receive everolimus 10 mg orally QD PLUS investigator's choice of fulvestrant 500 mg via IM injection on Days 1 and 15 of Cycle 1, and Day 1 of each 28-day cycle thereafter OR exemestane 25 mg orally QD until progressive disease or discontinuation.

Group Type ACTIVE_COMPARATOR

Fulvestrant

Intervention Type DRUG

Fulvestrant 500 mg administered as an IM injection.

Everolimus

Intervention Type DRUG

Administered at 10mg via oral tablets QD.

Exemestane

Intervention Type DRUG

Administered at 25 mg via oral tablets QD.

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Belzutifan

Belzutifan 120 mg administered QD as an oral tablet.

Intervention Type DRUG

Fulvestrant

Fulvestrant 500 mg administered as an IM injection.

Intervention Type DRUG

Everolimus

Administered at 10mg via oral tablets QD.

Intervention Type DRUG

Exemestane

Administered at 25 mg via oral tablets QD.

Intervention Type DRUG

Other Intervention Names

Discover alternative or legacy names that may be used to describe the listed interventions across different sources.

MK-6482

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* Has a diagnosis of estrogen receptor positive (ER+)/human epidermal growth factor receptor negative (HER2-) invasive breast carcinoma that is either locally advanced disease not amenable to resection or metastatic disease not treatable with curative intent
* Has documented radiographic confirmation of disease progression during or after the last administered endocrine therapy (ET)
* Provides additional tissue from the same sample used to determine ER and HER2 status locally
* Has received ET in the noncurative setting and has 1) Radiographic disease progression on 12 months or more of ET in combination with CDK4/6 inhibitor in the noncurative setting or 2) Received 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
* Has an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 assessed within 7 days of randomization
* Participants who have AEs due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline. Participants with endocrine-related AEs who are adequately treated with hormone replacement or participants who have ≤Grade 2 neuropathy are eligible
* Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks prior to the first dose of study intervention and have undetectable HBV viral load prior to randomization

Exclusion Criteria

* Has Breast cancer amenable to treatment with curative intent
* Is unable to receive any of the endocrine therapies (ETs) (ie, fulvestrant or exemestane)
* Has known difficulty in tolerating oral medications, unable to swallow orally administered medication, or conditions which would impair absorption of oral medications such as uncontrolled nausea or vomiting (ie, CTCAE =Grade 3 despite antiemetic therapy), ongoing gastrointestinal obstruction, motility disorder, malabsorption syndrome, or prior gastric bypass
* Has advanced/metastatic, symptomatic visceral spread at risk of rapidly evolving into life-threatening complications
* Has active, bleeding diathesis, or on oral anti-vitamin K medication
* Has history of noninfectious pneumonitis/interstitial lung disease including radiation pneumonitis that required steroids or has current pneumonitis/interstitial lung disease
* Has a 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
* Has received prior fulvestrant in the adjuvant, unresectable locally advanced, or metastatic setting
* Has received any line of cytotoxic chemotherapy or PARP inhibitor in the unresectable or noncurative advanced/metastatic setting
* Has received prior radiotherapy for non-central nervous system (CNS) disease or required corticosteroids for radiation-related toxicities including radiation pneumonitis, within 14 days of the first dose of study intervention
* Is currently receiving either a strong inhibitor or inducer of CYP3A4 that cannot be discontinued for the duration of the study
* Has received prior systemic anticancer therapy including investigational agents within 4 weeks before randomization
* Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention
* Has concurrent active Hepatitis B and Hepatitis C virus infection
* Has clinically significant cardiac disease, including unstable angina, acute myocardial infarction within 6 months from Day 1 of study medication administration, or New York Heart Association Class III or Class IV congestive heart failure
* Has not adequately recovered from major surgery or have ongoing surgical complications
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Merck Sharp & Dohme LLC

INDUSTRY

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

Responsibility Role SPONSOR

Principal Investigators

Learn about the lead researchers overseeing the trial and their institutional affiliations.

Medical Director

Role: STUDY_DIRECTOR

Merck Sharp & Dohme LLC

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

City of Hope - Phoenix ( Site 0006)

Goodyear, Arizona, United States

Site Status RECRUITING

Cedars Sinai Medical Center ( Site 0012)

Beverly Hills, California, United States

Site Status RECRUITING

Moores Cancer Center at UC San Diego Health ( Site 0025)

La Jolla, California, United States

Site Status RECRUITING

USC/Norris Comprehensive Cancer Center ( Site 0013)

Los Angeles, California, United States

Site Status RECRUITING

USC Norris Oncology Hematology Newport Beach ( Site 0029)

Newport Beach, California, United States

Site Status RECRUITING

Northwest Georgia Oncology Centers, a Service of Wellstar Cobb Hospital ( Site 0011)

Marietta, Georgia, United States

Site Status COMPLETED

Southeastern Regional Medical Center ( Site 0010)

Newnan, Georgia, United States

Site Status RECRUITING

CHRISTUS Highland ( Site 0005)

Shreveport, Louisiana, United States

Site Status COMPLETED

Renown Regional Medical Center ( Site 0018)

Reno, Nevada, United States

Site Status RECRUITING

MD Anderson Cancer Center at Cooper ( Site 0024)

Camden, New Jersey, United States

Site Status RECRUITING

MD Anderson ( Site 0015)

Houston, Texas, United States

Site Status RECRUITING

Mays Cancer Center ( Site 0022)

San Antonio, Texas, United States

Site Status RECRUITING

SSM Health Dean Medical Group - South Madison Campus Health Research/Circuit Clinical ( Site 0034)

Madison, Wisconsin, United States

Site Status RECRUITING

Medical College of Wisconsin - Froedtert Hospital ( Site 0014)

Milwaukee, Wisconsin, United States

Site Status RECRUITING

Centro de Investigaciones Metabólicas (CINME)-Oncology ( Site 0504)

CABA, Buenos Aires, Argentina

Site Status RECRUITING

Hospital Británico de Buenos Aires-Oncology ( Site 0500)

Ciudad Autónoma de Buenos Aires, Buenos Aires, Argentina

Site Status RECRUITING

Instituto de Investigaciones Clínicas Mar del Plata ( Site 0502)

Mar del Plata, Buenos Aires, Argentina

Site Status RECRUITING

Instituto Alexander Fleming-Alexander Fleming ( Site 0505)

Buenos Aires, Buenos Aires F.D., Argentina

Site Status RECRUITING

Sanatorio Allende - Cerro-Oncology ( Site 0506)

Córdoba, Córdoba Province, Argentina

Site Status RECRUITING

Instituto de Oncología de Rosario ( Site 0501)

Rosario, Santa Fe Province, Argentina

Site Status RECRUITING

Hospital Italiano de Córdoba ( Site 0508)

Córdoba, , Argentina

Site Status RECRUITING

Jewish General Hospital ( Site 0400)

Montreal, Quebec, Canada

Site Status RECRUITING

Centro de Investigación del Maule ( Site 4106)

Talca, Maule Region, Chile

Site Status RECRUITING

FALP ( Site 4102)

Santiago, Region M. de Santiago, Chile

Site Status RECRUITING

Pontificia Universidad Catolica de Chile ( Site 4108)

Santiago, Region M. de Santiago, Chile

Site Status RECRUITING

Bradfordhill ( Site 4100)

Santiago, Region M. de Santiago, Chile

Site Status RECRUITING

IMAT S.A.S ( Site 1205)

Montería, Departamento de Córdoba, Colombia

Site Status RECRUITING

Oncologos Del Occidente ( Site 1200)

Pereira, Risaralda Department, Colombia

Site Status RECRUITING

Fundacion Valle del Lili ( Site 1204)

Cali, Valle del Cauca Department, Colombia

Site Status RECRUITING

Seoul National University Hospital ( Site 3100)

Seoul, , South Korea

Site Status RECRUITING

Samsung Medical Center ( Site 3101)

Seoul, , South Korea

Site Status RECRUITING

National Cheng Kung University Hospital ( Site 3300)

Tainan, , Taiwan

Site Status RECRUITING

National Taiwan University Hospital ( Site 3301)

Taipei, , Taiwan

Site Status RECRUITING

National Taiwan University Cancer Center ( Site 3302)

Taipei, , Taiwan

Site Status RECRUITING

Faculty of Medicine Siriraj Hospital ( Site 3500)

Bangkoknoi, Bangkok, Thailand

Site Status RECRUITING

Faculty of Medicine - Khon Kaen University ( Site 3502)

Muang, Changwat Khon Kaen, Thailand

Site Status RECRUITING

Songklanagarind Hospital ( Site 3501)

Hat Yai, Changwat Songkhla, Thailand

Site Status RECRUITING

The Royal Cornwall Hospital ( Site 1904)

Truro, England, United Kingdom

Site Status RECRUITING

St Bartholomews Hospital ( Site 1900)

London, London, City of, United Kingdom

Site Status RECRUITING

The Christie Hospital NHS Foundation Trust ( Site 1902)

Withington, Manchester, United Kingdom

Site Status RECRUITING

Ipswich Hospital ( Site 1911)

Ipswich, Suffolk, United Kingdom

Site Status RECRUITING

Countries

Review the countries where the study has at least one active or historical site.

United States Argentina Canada Chile Colombia South Korea Taiwan Thailand United Kingdom

Central Contacts

Reach out to these primary contacts for questions about participation or study logistics.

Toll Free Number

Role: CONTACT

Phone: 1-888-577-8839

Email: [email protected]

Facility Contacts

Find local site contact details for specific facilities participating in the trial.

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Study Coordinator

Role: primary

Related Links

Access external resources that provide additional context or updates about the study.

https://www.merckclinicaltrials.com/

Merck Clinical Trials Information

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

MK-6482-029

Identifier Type: OTHER

Identifier Source: secondary_id

LITESPARK-029

Identifier Type: OTHER

Identifier Source: secondary_id

6482-029

Identifier Type: -

Identifier Source: org_study_id