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

Merck Sharp & Dohme (MSD)

Status and phase: Enrolling; Phase 2; Phase 1

Conditions: Malignant Neoplasm

Treatments: Biological: Patritumab Deruxtecan

Study type: Interventional

Funder types: Industry

Identifiers

NCT06941272

MK-9999-01C (Other Identifier)

LIGHTBEAM-U01 (Other Identifier)

2024-518771-66-00 (Registry Identifier)

9999-01C

U1111-1314-1866 (Registry Identifier)

Details and patient eligibility

About

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

Full 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)

Enrollment: 50 estimated patients

Sex: All

Ages: 1 month to 17 years old

Volunteers: No Healthy Volunteers

Inclusion and exclusion criteria

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 (noninfectious) interstitial lung disease (ILD)/pneumonitis that required steroids or has current ILD/pneumonitis, and/or suspected ILD/pneumonitis that cannot be ruled out by standard diagnostic assessments
• 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 design

Primary purpose: Treatment

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

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50 participants in 1 patient group

Patritumab Deruxtecan

Experimental group

Description:

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

Treatment:

Biological: Patritumab Deruxtecan