Malignant NeoplasmPhase 2NCT07700758
A Study of Belzutifan in Adolescent Participants With Solid Tumors (MK-9999-01E/LIGHTBEAM-U01)
A Phase 2 study testing Belzutifan in people with Malignant Neoplasm, run by Merck Sharp & Dohme LLC at 4 sites in 4 countries.
Trial summary
Researchers are looking for new ways to treat adolescents with locally advanced, unresectable, or metastatic solid tumors. Participants were enrolled into pheochromocytoma/paraganglioma (PPGL), wild type gastrointestinal stromal tumor (wtGIST), and Von Hippel-Lindau (VHL) disease-associated localized tumors cohorts… Read more about this study
- Who is it for?
- Ages 12 to 17 years
- Conditions the study is for
- Malignant Neoplasm
- What is being tested?
- Belzutifan
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 15 participants
- Where
- 4 sitesin 4 countries
- Study dates
- 13 Oct 2026to 2 Jan 2034
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 17 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- The main inclusion criteria include but are not limited to the following:
- Has a diagnosis of one of the following: locally advanced, unresectable, or metastatic pheochromocytoma/paraganglioma or wild-type gastrointestinal stromal tumors, or localized tumors associated with von Hippel-Lindau disease
- Has measurable disease per RECIST 1.1
Who cannot join
- The main exclusion criteria include but are not limited to the following:
- Has a pulse oximeter reading <92% at rest, requires intermittent supplemental oxygen, or requires chronic supplemental oxygen
- Has clinically significant cardiac disease or electrocardiogram indicating uncontrolled cardiac condition or has congenital long QT syndrome
- Has a history of human immunodeficiency virus infection
- Has received prior treatment with any hypoxia inducible factor-2α inhibitor, including belzutifan
- Has had an allogenic tissue/solid organ transplant
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- Has a history of autologous stem cell transplant within 6 months of start of study intervention
- Has known additional malignancy that is progressing or has required active treatment within the past 2 years
- Has known active central nervous system metastases and/or carcinomatous meningitis
- Has an active infection requiring systemic therapy
Trial locations and contacts
4 sites in 4 countries. Contact the study team or a site near you to ask about taking part.
4 sites in 4 countries
United States1 site, 1 recruiting
- Recruiting
University of Iowa ( Site 5017)
Iowa City, Iowa, 52242
Study Coordinator, 319-356-2296
Belgium1 site, 1 recruiting
- Recruiting
UZ Gent ( Site 5428)
Ghent, Oost-Vlaanderen, 9000
Study Coordinator, +32 9 332 16 53
South Korea1 site, 1 recruiting
- Recruiting
Seoul National University Hospital-Pediatrics ( Site 5972)
Seoul, 03080
Study Coordinator, +82-2-2072-1673
Spain1 site, 1 recruiting
- Recruiting
Hospital Infantil Universitario Nino Jesus ( Site 5715)
Madrid, 28009
Study Coordinator, +34915035900 ext 662
About this study
Official title: LIGHTBEAM-U01 Substudy 01E: A Phase 2 Substudy to Evaluate the Safety and Efficacy of Belzutifan in Participants With Solid Tumors
Researchers are looking for new ways to treat adolescents with locally advanced, unresectable, or metastatic solid tumors. Participants were enrolled into pheochromocytoma/paraganglioma (PPGL), wild type gastrointestinal stromal tumor (wtGIST), and Von Hippel-Lindau (VHL) disease-associated localized tumors cohorts:
- PPGL are rare cancers that start in cells that make hormones in the adrenal glands
- wtGIST is a less common type of cancer that starts in the digestive tract. Wild type means it does not have certain gene mutations (changes)
- VHL disease-associated localized tumors are rare tumors caused by a certain gene mutation that may be passed down from parents to children
- Locally advanced means the cancer has spread into nearby tissue
- Unresectable means the cancer cannot be removed by surgery
- Metastatic means the cancer has spread to other parts of the body
The goal of the study is to learn about the safety of belzutifan and if people tolerate it.
- Conditions
- Malignant Neoplasm
- Being tested
- Belzutifan
- Medical subject headings
- Neoplasms
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
BelzutifanDrug
Also called MK-6482, PT2977, WELIREG®
Administered once daily via oral tablet
| Study group | Role | What they receive |
|---|---|---|
| Belzutifan | Experimental | Participants will receive belzutifan 80 mg (body weight <40 kg) or 120 mg (body weight ≥40 kg) orally once daily for approximately 2 years. Receives: Drug: Belzutifan |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants Who Experience One or More Adverse Events (AEs)
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants that experience AEs will be reported.
Measured: Up to approximately 5 years
Number of Participants Who Discontinue Study Intervention Due to an AE
An AE is any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of a study intervention. The number of participants that discontinue study intervention due to an AE will be reported.
Measured: Up to approximately 5 years
Secondary outcomes (5)
Area Under the Concentration-Time Curve From Time 0 to 24 hours of Belzutifan
Blood samples will be collected at specified intervals to determine the area under the concentration-time curve from time 0 to 24 hours of belzutifan.
Measured: At designated timepoints (up to 5 weeks)
Minimum Plasma Concentration (Cmin) of Belzutifan
Blood samples will be collected at specified intervals to determine the Cmin of belzutifan.
Measured: At designated timepoints (up to 5 weeks)
Maximum Plasma Concentration (Cmax) of Belzutifan
Blood samples will be collected at specified intervals to determine the Cmax of belzutifan.
Measured: At designated timepoints (up to 5 weeks)
Objective Response Rate (ORR)
ORR is defined as the percentage of participants with Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1). The percentage of participants who experience CR or PR as assessed by investigator will be reported.
Measured: Up to approximately 5 years
Duration of Response (DOR)
For participants who demonstrate a confirmed Complete Response (CR: disappearance of all target lesions) or Partial Response (PR: at least a 30% decrease in the sum of diameters of target lesions) per Response Evaluation Criteria In Solid Tumors Version 1.1 (RECIST 1.1), DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per RECIST 1.1, PD is defined as at least a 20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is also considered PD. DOR as assessed by investigator will be reported.
Measured: Up to approximately 5 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jul 2026
- Study start13 Oct 2026
- Primary completion2 Jan 2034 (estimated)
- Study completion2 Jan 2034 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Malignant NeoplasmStudies of the same condition, open and under way.
- More trials run by Merck Sharp & Dohme LLCThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 15 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Merck Sharp & Dohme LLC
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Medical Director, Study director, Merck Sharp & Dohme LLC
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07700758
- Sponsor's protocol ID
- 9999-01E
- Other IDs
- U1111-1330-9370, 2025-524515-37-00, MK-9999-01E, LIGHTBEAM-U01, 2025
- Status last verified
- Oct 2026
- First submitted
- 8 Jul 2026
- Last updated
- 23 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf