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Malignant NeoplasmPhase 1/2NCT06941272

A Study of Patritumab Deruxtecan in Pediatric Participants With Relapsed or Refractory Solid Tumors (MK-9999-01C/LIGHTBEAM-U01)

A Phase 1/2 study testing Patritumab Deruxtecan in people with Malignant Neoplasm, run by Merck Sharp & Dohme LLC at 64 sites in 23 countries.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record

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Trial summary

Researchers are looking for new ways to treat children with hepatoblastoma or rhabdomyosarcoma (RMS) that has relapsed or is refractory: Hepatoblastoma is a common liver cancer in babies and very young children RMS is a cancer that starts in muscle cells, often in a child's head and neck, bladder, arms, or legs… Read more about this study

Who is it for?
Ages 1 month to 17 years
Conditions the study is for
Malignant Neoplasm
What is being tested?
Patritumab Deruxtecan
Type of treatment
Injection or infusion
Could I receive a placebo?
No, everyone receives an active treatment
How many people
50 participants
Where
64 sitesin 23 countries
Study dates
26 May 2025to 30 Dec 2030
Phase
Phase 1/2

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 1 month to 17 years
  • All sexes
  • No healthy volunteers
  • Child

The main inclusion criteria include but are not limited to the following:

  • Has one of the following histologically confirmed advanced or metastatic solid tumors: Rhabdomyosarcoma (RMS), or Hepatoblastoma
  • Has progressed after at least 1 prior systemic treatment for RMS or hepatoblastoma and who has no satisfactory alternative treatment option (ie, is ineligible for other standard treatment regimens)
  • Participants who have adverse events (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 with Grade ≤2 alopecia are also eligible
  • Hepatitis B surface antigen (HBsAg) positive participants are eligible if they have received hepatitis B virus (HBV) antiviral therapy and have undetectable HBV viral load
  • Participants with a history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable

The main exclusion criteria include but are not limited to the following:

  • Has a history of interstitial lung disease (ILD)/pneumonitis irrespective of steroid use, or current ILD/pneumonitis, or suspected ILD/pneumonitis, or ILD that cannot be ruled out by imaging
  • Has clinically severe respiratory compromise resulting from intercurrent pulmonary illness
  • Has a history of solid organ transplant
  • Has a history of allogeneic stem cell transplant
  • Has clinically significant corneal disease
  • Has known active central nervous system (CNS) metastases and/or carcinomatous meningitis/leptomeningeal disease; participants with previously treated brain metastases may participate provided they are radiologically stable (ie, without evidence of progression) for at least 4 weeks
  • Has uncontrolled or significant cardiovascular disorder
  • Has a history of clinically significant congenital cardiac syndrome
  • Has a history of human immunodeficiency virus (HIV) infection
  • Has a known additional malignancy that is progressing or has required active treatment within the past 1 year
  • Has an active infection requiring systemic therapy
  • Has concurrent active hepatitis B (HBsAg positive and/or detectable HBV deoxyribonucleic acid [DNA]) and HCV defined as anti-HCV antibody (Ab) positive and detectable HCV ribonucleic acid [RNA]) infection
  • Has not adequately recovered from major surgery or have ongoing surgical complications

Trial locations and contacts

64 sites in 23 countries. Contact the study team or a site near you to ask about taking part.

Toll Free Number contact

1-888-577-8839

Trialsites@msd.com

64 sites in 23 countries

United States17 sites, 17 recruiting

  • Children's Hospital Colorado-Center for Cancer and Blood Disorders ( Site 3016)

    Aurora, Colorado, 80045

    Study Coordinator, 720-777-1234

    Recruiting

  • Dana-Farber Cancer Institute ( Site 3013)

    Boston, Massachusetts, 02215

    Study Coordinator, 617-632-4580

    Recruiting

  • Sanford Fargo Medical Center-Roger Maris Cancer Center ( Site 3003)

    Fargo, North Dakota, 58102

    Study Coordinator, 701-234-2000

    Recruiting

  • Corewell Health ( Site 3001)

    Grand Rapids, Michigan, 49503

    Study Coordinator, 616-486-0746

    Recruiting

  • University of Texas-MD Anderson Cancer Center ( Site 3007)

    Houston, Texas, 77030

    Study Coordinator, 713-792-5410

    Recruiting

  • University of Iowa Health Care Holden Comprehensive Cancer Center ( Site 3017)

    Iowa City, Iowa, 52242

    Study Coordinator, 319-356-2296

    Recruiting

  • Children's Mercy Hospital ( Site 3024)

    Kansas City, Missouri, 64108

    Study Coordinator, 816-302-6808

    Recruiting

  • Childrens Hospital Los Angeles ( Site 3006)

    Los Angeles, California, 90027

    Study Coordinator, 323-361-2121

    Recruiting

  • Rutgers Cancer Institute of New Jersey ( Site 3008)

    New Brunswick, New Jersey, 08901

    Study Coordinator, 732-235-2465

    Recruiting

  • Yale New Haven Hospital ( Site 3012)

    New Haven, Connecticut, 06510

    Study Coordinator, 203-785-4640

    Recruiting

  • Memorial Sloan Kettering Cancer Center ( Site 3010)

    New York, New York, 10065

    Study Coordinator, 888-492-8401

    Recruiting

  • Children's Hospital of Philadelphia (CHOP) ( Site 3021)

    Philadelphia, Pennsylvania, 19104

    Study Coordinator, 267-425-5544

    Recruiting

  • Oregon Health and Science University ( Site 3004)

    Portland, Oregon, 97239

    Study Coordinator, 503-494-8311

    Recruiting

  • Intermountain - Primary Children's Hospital ( Site 3014)

    Salt Lake City, Utah, 84113

    Study Coordinator, 801-662-4700

    Recruiting

  • Sanford Children's Hospital ( Site 3015)

    Sioux Falls, South Dakota, 57117

    Study Coordinator, 605-312-1000

    Recruiting

  • Johns Hopkins All Children's Hospital ( Site 3025)

    St. Petersburg, Florida, 33701

    Study Coordinator, 727-767-4176

    Recruiting

  • New York Medical College ( Site 3023)

    Valhalla, New York, 10595

    Study Coordinator, 914-614-4270

    Recruiting

Other trials in United States

France5 sites, 5 recruiting

  • Bordeaux University Hospital - Pellegrin ( Site 3105)

    Bordeaux, Aquitaine, 33076

    Study Coordinator, +33556795679

    Recruiting

  • Centre Leon-Berard ( Site 3100)

    Lyon, Rhone, 69373

    Study Coordinator, 33469166572

    Recruiting

  • Assistance Publique Hôpitaux de Marseille - Hôpital de la Timone ( Site 3102)

    Marseille, Bouches-du-Rhone, 13005

    Study Coordinator, +33491385238

    Recruiting

  • Centre Hospitalier Universitaire de Nantes - Hôpital Femme-Enfant-Adolescent Chu De Nantes ( Site 3104)

    Nantes, Loire-Atlantique, 44093

    Study Coordinator, +33240083610

    Recruiting

  • Institut Curie ( Site 3101)

    Paris, Île-de-France Region, 75248

    Study Coordinator, +33144324015

    Recruiting

Other trials in France

United Kingdom4 sites, 4 recruiting

  • Birmingham Children's Hospital ( Site 3349)

    Birmingham, England, B4 6NH

    Study Coordinator, +441213338233

    Recruiting

  • University Hospital of Wales ( Site 3346)

    Cardiff, CF14 4XW

    Study Coordinator, +4402921842107

    Recruiting

  • Royal Victoria Infirmary ( Site 3348)

    Newcastle upon Tyne, England, NE1 4PL

    Study Coordinator, 0191 282 1014

    Recruiting

  • Royal Marsden Hospital ( Site 3347)

    Sutton, SM2 5PT

    Study Coordinator, 020 8642 6011

    Recruiting

Other trials in United Kingdom

Australia3 sites, 3 recruiting

  • Queensland Children's Hospital ( Site 3996)

    Brisbane, Queensland, 4101

    Study Coordinator, 61730681111

    Recruiting

  • Royal Children's Hospital ( Site 3994)

    Parkville, Victoria, 3052

    Study Coordinator, 61393455522

    Recruiting

  • Sydney Children's Hospital-Kids Cancer Centre ( Site 3997)

    Sydney, New South Wales, 2031

    Study Coordinator, 61293821111

    Recruiting

Other trials in Australia

Brazil3 sites, 3 recruiting

  • Fundação Pio XII - Hospital de Câncer de Barretos ( Site 3264)

    Barretos, São Paulo, 14784-400

    Study Coordinator, +551733216638

    Recruiting

  • Hospital de Clinicas de Porto Alegre ( Site 3265)

    Porto Alegre, Rio Grande do Sul, 90035-903

    Study Coordinator, +5551980139616

    Recruiting

  • Fundação Faculdade Regional de Medicina de São José do Rio Preto ( Site 3267)

    São José do Rio Preto, São Paulo, 15090-000

    Study Coordinator, +55 17 99625-3919

    Recruiting

Other trials in Brazil

Colombia3 sites, 3 recruiting

  • Clinica de la Costa S.A.S. ( Site 3924)

    Barranquilla, Atlántico, 080020

    Study Coordinator, +573008096054

    Recruiting

  • Hospital Pablo Tobon Uribe ( Site 3923)

    Medellín, Antioquia, 05034

    Study Coordinator, +57 3006523572

    Recruiting

  • IMAT S.A.S ( Site 3921)

    Montería, Departamento de Córdoba, 230002

    Study Coordinator, +576047862333

    Recruiting

Other trials in Colombia

Germany3 sites, 3 recruiting

  • Universitaetsklinikum Koeln. Klinik und Poliklinik ( Site 3145)

    Cologne, North Rhine-Westphalia, 50937

    Study Coordinator, 0049221 478 6831

    Recruiting

  • Universitätsklinikum Münster - Albert Schweitzer Campus ( Site 3141)

    Münster, North Rhine-Westphalia, 48149

    Study Coordinator, +492518347742

    Recruiting

  • UniversitaetsklInikum Tuebingen ( Site 3142)

    Tübingen, Baden-Wurttemberg, 72076

    Study Coordinator, +4970712981469

    Recruiting

Other trials in Germany

Italy3 sites, 3 recruiting

  • Fondazione IRCCS Istituto Nazionale dei Tumori ( Site 3552)

    Milan, 20133

    Study Coordinator, 00390223902593

    Recruiting

  • Ospedale Pediatrico Bambino Gesù IRCCS ( Site 3553)

    Roma, 00165

    Study Coordinator, 00390668593697

    Recruiting

  • Ospedale Infantile Regina Margherita ( Site 3551)

    Torino, 10126

    Study Coordinator, 00390113135230

    Recruiting

Other trials in Italy

Spain3 sites, 3 recruiting

  • Hospital Universitari Vall d''Hebron ( Site 3716)

    Barcelona, 08035

    Study Coordinator, +34915035900x662

    Recruiting

  • Hospital Sant Joan de Déu ( Site 3717)

    Esplugues de Llobregat, Barcelona, 08950

    Study Coordinator, +34671600093

    Recruiting

  • Hospital Infantil Universitario Nino Jesus ( Site 3715)

    Madrid, 28009

    Study Coordinator, +34915035900

    Recruiting

Other trials in Spain

Turkey (Türkiye)3 sites, 3 recruiting

  • Hacettepe Universitesi Tip Fakultesi Hastanesi ( Site 3961)

    Ankara, 06230

    Study Coordinator, +90 312 305 50 00

    Recruiting

  • Ankara Bilkent Şehir Hastanesi. ( Site 3962)

    Ankara, 6800

    Study Coordinator, +90 312 552 60 00

    Recruiting

  • Ege Universitesi Hastanesi ( Site 3963)

    Izmir, 35100

    Study Coordinator, +905301469380

    Recruiting

Other trials in Turkey (Türkiye)

Canada2 sites, 2 recruiting

  • Alberta Children's Hospital ( Site 3227)

    Calgary, Alberta, T3B 6A8

    Study Coordinator, 403-955-7203

    Recruiting

  • The Hospital for Sick Children ( Site 3225)

    Toronto, Ontario, M5G 1X8

    Study Coordinator, 4168131500

    Recruiting

Other trials in Canada

Czechia2 sites, 2 recruiting

  • Detska nemocnice FN Brno ( Site 3388)

    Brno, Brno-mesto, 613 00

    Study Coordinator, +420532234755

    Recruiting

  • Fakultni nemocnice v Motole-Klinika detske hematologie a onkologie ( Site 3387)

    Prague, Praha 5, 150 00

    Study Coordinator, +420224436475

    Recruiting

Other trials in Czechia

Israel2 sites, 2 recruiting

  • Rambam Health Care Campus ( Site 3674)

    Haifa, 3109601

    Study Coordinator, 97247774718

    Recruiting

  • Sheba Medical Center ( Site 3675)

    Ramat Gan, 5265601

    Study Coordinator, +97235302996

    Recruiting

Other trials in Israel

South Korea2 sites, 2 recruiting

  • Seoul National University Hospital-Pediatrics ( Site 3972)

    Seoul, 03080

    Study Coordinator, +82220723304

    Recruiting

  • Asan Medical Center-Pediatrics - Pedicatric Oncology ( Site 3973)

    Seoul, 05505

    Study Coordinator, +82230105994

    Recruiting

Other trials in South Korea

Belgium1 site, 1 recruiting

  • UZ Gent ( Site 3428)

    Ghent, Oost-Vlaanderen, 9000

    Study Coordinator, +3293324812

    Recruiting

Other trials in Belgium

Chile1 site, 1 recruiting

  • Hospital Carlos Van Buren ( Site 3880)

    Valparaíso, Valparaiso, 2341131

    Study Coordinator, 56978546125

    Recruiting

Other trials in Chile

Denmark1 site, 1 recruiting

  • Rigshospitalet-Department of paediatrics and adolescent medicine, Section of Paed haem-onc ( Site 3467)

    Copenhagen, Capital Region, DK-2100

    Study Coordinator, +4535452462

    Recruiting

Other trials in Denmark

Greece1 site, 1 recruiting

  • Aghia Sophia Children's Hospital-First Department of Pediatrics, National and Kapodistrian Universi ( Site 3797)

    Athens, Attica, 11527

    Study Coordinator, +302107452125

    Recruiting

Other trials in Greece

Hungary1 site, 1 recruiting

  • Semmelweis University ( Site 3838)

    Budapest, Pest County, 1094

    Study Coordinator, +3612151380

    Recruiting

Other trials in Hungary

Netherlands1 site, 1 recruiting

  • Prinses Maxima Centrum voor Kinderoncologie ( Site 3510)

    Utrecht, 3584 CS

    Study Coordinator, +31889727272

    Recruiting

Other trials in Netherlands

Slovakia1 site, 1 recruiting

  • Narodny ustav detskych chorob ( Site 3592)

    Bratislava, Bratislava Region, 833 40

    Study Coordinator, +421259371205

    Recruiting

Other trials in Slovakia

Sweden1 site, 1 recruiting

  • Sahlgrenska Universitetssjukhuset ( Site 3634)

    Gothenburg, Västra Götaland County, 416 85

    Study Coordinator, +46313435865

    Recruiting

Other trials in Sweden

Taiwan1 site, 1 recruiting

  • National Taiwan University Hospital ( Site 3983)

    Taiwan, Taipei, 10002

    Study Coordinator, 8862-23123456#70559

    Recruiting

Other trials in Taiwan

About this study

Official title: LIGHTBEAM-U01 Substudy 01C: A Phase 1/2 Substudy to Evaluate the Safety and Efficacy of Patritumab Deruxtecan in Pediatric Participants With Relapsed or Refractory Solid Tumors

Researchers are looking for new ways to treat children with hepatoblastoma or rhabdomyosarcoma (RMS) that has relapsed or is refractory:

  • Hepatoblastoma is a common liver cancer in babies and very young children
  • RMS is a cancer that starts in muscle cells, often in a child's head and neck, bladder, arms, or legs
  • Relapsed means the cancer came back after treatment
  • Refractory means the cancer did not respond (get smaller or go away) to treatment
Read more

The study treatment HER3-DXd (also known as MK-1022 or patritumab deruxtecan) is an antibody-drug conjugate (ADC). An ADC attaches to a protein on cancer cells and delivers treatment to destroy those cells. The goals of this study are to learn:

  • About the safety of HER3-DXd in children and if they tolerate it
  • What happens to HER3-DXd in children's bodies over time
  • If children who receive HER3-DXd have the cancer get smaller or go away
Read the detailed description

This study will have 2 parts: a safety lead-in to demonstrate a tolerable safety profile and confirm a preliminary recommended phase 2 dose (RP2D) (Part 1) followed by an efficacy evaluation (Part 2)

Being tested
Patritumab Deruxtecan
Medical subject headings
Neoplasms

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Patritumab DeruxtecanBiological

    Also called MK-1022, HER3-DXd, U3-1402

    IV Infusion

Study groups in NCT06941272
Study groupRoleWhat they receive
Patritumab DeruxtecanExperimentalParticipants receive patritumab deruxtecan via IV infusion on Day 1 of each 3-week cycle until discontinuation or progression.
Receives: Biological: Patritumab Deruxtecan

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Part 1: Percentage of Participants Who Experience Dose-limiting Toxicities (DLTs)

    A DLT is any of a prespecified list of adverse events (AEs) that occur during Cycle 1 (up to 21 days) if attributed to the study treatment and not attributed to any other clearly identifiable cause. The percentage of participants who experience DLTs will be reported. Each cycle is 21 days.

    Measured: Cycle 1 (up to approximately 21 days); each cycle is 21 days

  2. Part 1: Percentage of Participants Who Experience an Adverse Event (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 percentage of participants who experience AEs will be reported.

    Measured: Up to approximately 5 years

  3. Part 1: Percentage of Participants Who Discontinue Study Treatment 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 percentage of participants who discontinue study treatment due to an AE will be reported.

    Measured: Up to approximately 5 years

  4. Part 1: Area Under the Curve (AUC) of total anti-HER3 antibody liquid chromatography-mass spectrometry (LC-MS) in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  5. Part 1: AUC of anti-HER3 antibody-conjugated DXd (anti-HER3-ac-DXd) in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  6. Part 1: AUC of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  7. Part 1: Maximum Concentration (Cmax) of anti-HER3 antibody LC-MS in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  8. Part 1: Cmax of anti-HER3-ac-DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  9. Part 1: Cmax of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  10. Part 1: Concentration Immediately Before the Next Dose is Administered (Ctrough) of anti-HER3 antibody LC-MS in plasma

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (up to approximately 5 years)

  11. Part 1: Ctrough of anti-HER3-ac-DXd

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (up to approximately 5 years)

  12. Part 1: Ctrough of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (up to approximately 5 years)

  13. Part 1 and Part 2: 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 the investigator will be presented.

    Measured: Up to approximately 5 years

Secondary outcomes (16)

  1. Part 2: Percentage of Participants Who Experience 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 percentage of participants who experience AEs will be reported.

    Measured: Up to approximately 5 years

  2. Part 2: Percentage of Participants Who Discontinue Study Treatment 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 percentage of participants who discontinue study treatment due to an AE will be reported.

    Measured: Up to approximately 5 years

  3. Part 1 and Part 2: Disease Control Rate (DCR)

    DCR is defined, per RECIST 1.1, as the percentage of participants who have a CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions) or Stable Disease (SD). SD is defined as neither sufficient shrinkage to qualify for PR nor sufficient increase to qualify for progressive disease (PD: at least a 20% increase in the sum of diameters of target lesions and an absolute increase of at least 5 mm). Note: The appearance of one or more new lesions is also considered PD. The time from the first dose until the date of SD must be greater than or equal to 6 weeks. The DCR as assessed by the investigator will be presented.

    Measured: Up to approximately 5 years

  4. Part 1 and Part 2: Time to Response (TTR)

    For participants who demonstrate a confirmed CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1, TTR is defined as the time from the first dose to the first documented evidence of a CR or PR. The TTR as assessed by the investigator will be presented.

    Measured: Up to approximately 5 years

  5. Part 1 and Part 2: Duration of Response (DOR)

    For participants who demonstrate a confirmed CR (disappearance of all target lesions) or PR (at least a 30% decrease in the sum of diameters of target lesions) per RECIST 1.1, DOR is defined as the time from first documented evidence of CR or PR until PD or death. PD is defined as at least a 20% increase in the sum of diameters of target lesions and an absolute increase of at least 5 mm. Note: The appearance of one or more new lesions is also considered PD. DOR as assessed by the investigator will be presented.

    Measured: Up to approximately 5 years

  6. Part 1 and Part 2: Progression-free Survival (PFS)

    PFS is defined as the time from randomization to the first documented PD or death due to any cause, whichever occurs first as assessed by RECIST 1.1. PD is defined as at least a 20% increase in the sum of diameters of target lesions and an absolute increase of at least 5 mm. Note: The appearance of one or more new lesions is also considered PD. PFS as assessed by the investigator will be presented.

    Measured: Up to approximately 5 years

  7. Part 1 and Part 2: Overall Survival (OS)

    OS is defined as time from first dose of study treatment to death due to any cause.

    Measured: Up to approximately 5 years

  8. Part 2: AUC of total anti-HER3 antibody LC-MS in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  9. Part 2: AUC of anti-HER3-ac-DXd in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  10. Part 2: AUC of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of AUC.

    Measured: At designated timepoints (up to approximately 5 years)

  11. Part 2: Cmax of anti-HER3 antibody LC-MS in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  12. Part 2: Cmax of anti-HER3-ac-DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  13. Part 2: Cmax of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Cmax.

    Measured: At designated timepoints (up to approximately 5 years)

  14. Part 2: Ctrough of anti-HER3 antibody LC-MS in plasma

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (up to approximately 5 years)

  15. Part 2: Ctrough of anti-HER3-ac-DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (up to approximately 5 years)

  16. Part 2: Ctrough of DXd in plasma

    Blood samples will be collected at specified intervals for the determination of Ctrough.

    Measured: At designated timepoints (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.

  1. First posted23 Apr 2025
  2. Study start26 May 2025
  3. Primary completion30 Dec 2030 (estimated)
  4. Study completion30 Dec 2030 (estimated)

Resources

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 1/2
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrolment
50 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06941272
Sponsor's protocol ID
9999-01C
Other IDs
MK-9999-01C, LIGHTBEAM-U01, U1111-1314-1866, 2024-518771-66-00
Status last verified
Oct 2026
First submitted
27 Feb 2025
Last updated
6 Oct 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

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