A Phase 1/2 interventional study of Patritumab Deruxtecan in Malignant Neoplasm, sponsored by Merck Sharp & Dohme LLC. Recruiting at 64 sites in 23 countries. Open to participants aged 1 Month to 17 Years. Per ClinicalTrials.gov, last updated 2026-10-06.
Sponsored by Merck Sharp & Dohme LLC (part of Merck & Co., Inc) · Phase 1/2, Interventional, and Treatment
Researchers are looking for new ways to treat children with hepatoblastoma or rhabdomyosarcoma (RMS) that has relapsed or is refractory:
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:
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)
10,818 studies on the registry are indexed under Neoplasms; 2,324 are open to participants now.
This study's planned enrollment of 50 is below the median of 60 across 7,703 interventional studies indexed under Neoplasms.
Browse Neoplasms studies →Merck Sharp & Dohme LLC is the lead sponsor of 2,166 studies on the registry; 132 are open to participants now.
Of its 501 completed or terminated interventional studies of FDA-regulated products, 370 (74%) have results posted.
Counted across the registry records on this site, refreshed daily.
The main inclusion criteria include but are not limited to the following:
The main exclusion criteria include but are not limited to the following:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Leptomeningeal disease
Cancer that has spread to the leptomeninges, the thin layers covering the brain and spinal cord, and the fluid between them. It is not the same as brain metastases.
Criteria often treat it separately, and many studies leave it out even where treated brain metastases are allowed.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Brain metastases
Cancer deposits in the brain from a cancer that started elsewhere in the body (CNS metastases include the spinal cord).
Studies differ: some leave out any brain metastases, some accept ones treated and stable for some weeks. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive patritumab deruxtecan via IV infusion on Day 1 of each 3-week cycle until discontinuation or progression.
Biological: Patritumab Deruxtecan
IV Infusion
Also known as: MK-1022, HER3-DXd, U3-1402
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.
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)
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.
Time frame: Up to approximately 5 years
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.
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
Blood samples will be collected at specified intervals for the determination of AUC.
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
Blood samples will be collected at specified intervals for the determination of AUC.
Time frame: At designated timepoints (up to approximately 5 years)
Part 1: AUC of DXd in plasma
Blood samples will be collected at specified intervals for the determination of AUC.
Time frame: At designated timepoints (up to approximately 5 years)
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.
Time frame: At designated timepoints (up to approximately 5 years)
Part 1: Cmax of anti-HER3-ac-DXd in plasma
Blood samples will be collected at specified intervals for the determination of Cmax.
Time frame: At designated timepoints (up to approximately 5 years)
Part 1: Cmax of DXd in plasma
Blood samples will be collected at specified intervals for the determination of Cmax.
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
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
Part 1: Ctrough of anti-HER3-ac-DXd
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
Part 1: Ctrough of DXd in plasma
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: Up to approximately 5 years
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.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: AUC of anti-HER3-ac-DXd in plasma
Blood samples will be collected at specified intervals for the determination of AUC.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: AUC of DXd in plasma
Blood samples will be collected at specified intervals for the determination of AUC.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Cmax of anti-HER3 antibody LC-MS in plasma
Blood samples will be collected at specified intervals for the determination of Cmax.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Cmax of anti-HER3-ac-DXd in plasma
Blood samples will be collected at specified intervals for the determination of Cmax.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Cmax of DXd in plasma
Blood samples will be collected at specified intervals for the determination of Cmax.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Ctrough of anti-HER3 antibody LC-MS in plasma
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Ctrough of anti-HER3-ac-DXd in plasma
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
Part 2: Ctrough of DXd in plasma
Blood samples will be collected at specified intervals for the determination of Ctrough.
Time frame: At designated timepoints (up to approximately 5 years)
Plan to share: Yes — https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf
Data sharing details ↗ · externaldatasharing-msd.com
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: Patritumab deruxtecan