Recruiting
Phase 1
Phase 2

HER3-DXd

Sponsor:

Merck Sharp & Dohme LLC

Code:

NCT06941272

Conditions

Malignant Neoplasm

Eligibility Criteria

Sex: All

Age: 0 - 17

Healthy Volunteers: Not accepted

Interventions

Patritumab Deruxtecan

Study Details

Brief 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
  • Relapsed means the cancer came back after treatment
  • Refractory means the cancer did not respond (get smaller or go away) to treatment

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

Conditions

Malignant Neoplasm

Study ID

NCT06941272

Start date

May 26, 2025

Status verified date

Aug, 2026

Completion date

Dec 30, 2030

Anticipated

Primary completion date

Dec 30, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 0 - 17

Healthy Volunteers: Not accepted

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

Study Design

Enrollment

50 participants

Anticipated

Intervention Model

Single group

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Patritumab Deruxtecan

Participants receive patritumab deruxtecan via IV infusion on Day 1 of each 3-week cycle until discontinuation or progression.

Interventions

Patritumab Deruxtecan

IV Infusion

Primary outcome measure

  • Part 1: Percentage of Participants Who Experience Dose-limiting Toxicities (DLTs) [ Time Frame: Cycle 1 (up to approximately 21 days); each cycle is 21 days ]
  • Part 1: Percentage of Participants Who Experience an Adverse Event (AE) [ Time Frame: Up to approximately 5 years ]
  • Part 1: Percentage of Participants Who Discontinue Study Treatment Due to an AE [ Time Frame: Up to approximately 5 years ]
  • Part 1: Area Under the Curve (AUC) of total anti-HER3 antibody liquid chromatography-mass spectrometry (LC-MS) in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: AUC of anti-HER3 antibody-conjugated DXd (anti-HER3-ac-DXd) in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: AUC of DXd in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Maximum Concentration (Cmax) of anti-HER3 antibody LC-MS in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Cmax of anti-HER3-ac-DXd in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Cmax of DXd in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Concentration Immediately Before the Next Dose is Administered (Ctrough) of anti-HER3 antibody LC-MS in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Ctrough of anti-HER3-ac-DXd [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1: Ctrough of DXd in plasma [ Time Frame: At designated timepoints (up to approximately 5 years) ]
  • Part 1 and Part 2: Objective Response Rate (ORR) [ Time Frame: Up to approximately 5 years ]

Central Contacts and Locations

Central contacts

Toll Free Number

1-888-577-8839Trialsites@msd.com

Locations

Childrens Hospital Los Angeles ( Site 3006)

Recruiting

Los Angeles, California, United States, 90027

Contacts

Study Coordinator

323-361-2121

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

Recruiting

Aurora, Colorado, United States, 80045

Contacts

Study Coordinator

720-777-1234

Johns Hopkins All Children's Hospital ( Site 3025)

Recruiting

St. Petersburg, Florida, United States, 33701

Contacts

Study Coordinator

727-767-4176

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

Recruiting

Iowa City, Iowa, United States, 52242

Contacts

Study Coordinator

319-356-2296

Dana-Farber Cancer Institute ( Site 3013)

Recruiting

Boston, Massachusetts, United States, 02215

Contacts

Study Coordinator

617-632-4580

Corewell Health ( Site 3001)

Recruiting

Grand Rapids, Michigan, United States, 49503

Contacts

Study Coordinator

616-486-0746

Children's Mercy Hospital ( Site 3024)

Recruiting

Kansas City, Missouri, United States, 64108

Contacts

Study Coordinator

816-302-6808

Rutgers Cancer Institute of New Jersey ( Site 3008)

Recruiting

New Brunswick, New Jersey, United States, 08901

Contacts

Study Coordinator

732-235-2465

Memorial Sloan Kettering Cancer Center ( Site 3010)

Recruiting

New York, New York, United States, 10065

Contacts

Study Coordinator

888-492-8401

New York Medical College ( Site 3023)

Recruiting

Valhalla, New York, United States, 10595

Contacts

Study Coordinator

914-614-4270

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

Recruiting

Fargo, North Dakota, United States, 58102

Contacts

Study Coordinator

701-234-2000

Oregon Health and Science University ( Site 3004)

Recruiting

Portland, Oregon, United States, 97239

Contacts

Study Coordinator

503-494-1080

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

Recruiting

Philadelphia, Pennsylvania, United States, 19104

Contacts

Study Coordinator

267-425-5544

Sanford Children's Hospital ( Site 3015)

Recruiting

Sioux Falls, South Dakota, United States, 57117

Contacts

Study Coordinator

605-312-1000

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

Recruiting

Houston, Texas, United States, 77030

Contacts

Study Coordinator

713-792-5410

Intermountain - Primary Children's Hospital ( Site 3014)

Recruiting

Salt Lake City, Utah, United States, 84113

Contacts

Study Coordinator

801-662-4700

More Information

Sponsor

Merck Sharp & Dohme LLC

Last update posted

Aug 28, 2026

Last verified

Aug, 2026

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-08. This information was provided to ClinicalTrials.gov by Merck Sharp & Dohme LLC on 2026-08-28.