NCT06686394 · Merck Sharp & Dohme LLC
Study of Patritumab Deruxtecan With Other Anticancer Agents in Participants With HER2 Positive Breast Cancer That Has Spread and Cannot Be Surgically Removed (MK-1022-009)
What this study is about
Researchers want to learn if patritumab deruxtecan (MK-1022) can treat certain breast cancers. The breast cancers being studied are HER2 positive unresectable locally advanced or metastatic (the cancer has spread to other parts of the body).
View original scientific description
Researchers want to learn if patritumab deruxtecan (MK-1022) can treat certain breast cancers. The breast cancers being studied are HER2 positive unresectable locally advanced or metastatic (the cancer has spread to other parts of the body).
Interventions
BIOLOGICAL
Patritumab deruxtecan
Patritumab deruxtecan administered via IV infusion
BIOLOGICAL
Trastuzumab
Trastuzumab administered via IV infusion
BIOLOGICAL
Trastuzumab Biosimilar
Trastuzumab biosimilar administered via IV infusion
BIOLOGICAL
Pertuzumab
Pertuzumab administered via IV infusion
BIOLOGICAL
Tucatinib
Tucatinib administered as oral tablets
Primary outcome measures
Number of Participants Experiencing Dose-Limiting Toxicity (DLT)
Time frame: Up to 21 days
DLT will be defined as any drug-related AE observed during the DLT evaluation period that results in a change to a given dose or a delay in initiating the next cycle. The number of participants who experience a DLT will be presented.
Number of Participants with One or More Adverse Events (AEs)
Time frame: Up to approximately 13 months
An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment. The number of participants who experience an AE will be presented.
Number of Participants who Discontinue Study Intervention Due to an AE
Time frame: Up to approximately 12 months
An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment. The number of participants who discontinue study treatment due to an AE will be presented.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- The main inclusion criteria include but are not limited to the following:
- Has histologically confirmed HER2+ locally advanced unresectable breast cancer or metastatic breast cancer
- Human immunodeficiency virus (HIV)-infected participants must have well-controlled HIV on antiretroviral therapy (ART)
- Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received HBV antiviral therapy for at least 4 weeks, and have undetectable hepatitis B virus (HBV) viral load before allocation
- Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable
- Eastern Cooperative Oncology Group (ECOG) performance status 0 to 1 within 7 days before start of study intervention Arm 1:
- Has received at least a minimum of 2 and a maximum of 5 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting
- Had disease progression on or after any previous trastuzumab deruxtecan (
Where
- Aurora, Colorado
- Boston, Massachusetts
- New Brunswick, New Jersey
- Greenville, South Carolina
- Fairfax, Virginia
Collaborators
Daiichi Sankyo
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced May 22, 2026 · Source of record for eligibility and locations