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AzTrials

Breast NeoplasmsPhase 1/2NCT06686394

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)

A Phase 1/2 study testing Patritumab deruxtecan, Trastuzumab and Trastuzumab Biosimilar in people with Breast Neoplasms and Breast Cancer, run by Merck Sharp & Dohme LLC at 18 sites in 6 countries.

Recruiting

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

Sites and contacts
Official record
Search all trials

Trial summary

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). Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Breast Neoplasms, Breast Cancer
What is being tested?
Patritumab deruxtecan, Trastuzumab and Trastuzumab Biosimilar
Could I receive a placebo?
No, everyone receives an active treatment
How many people
181 participants
Where
18 sitesin 6 countries
Study dates
26 Feb 2025to 2 Aug 2032
Phase
Phase 1/2
Are there results?
Not yet: the study is under way

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 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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
Show all 14Show fewer
  • Part 1 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 (T-DXd) treatment
  • Part 1 Arm 2:
  • -Has received no more than 5 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting
  • Part 1 Arm 3:
  • -Has received and had disease progression from T-DXd treatment in any setting and a maximum of 3 prior lines of anti-HER2 therapy in the locally advanced or metastatic setting. T-DXd must be the most recent therapy received before enrollment.
  • Part 2 : Has not received prior systemic therapy (including T-DXd) for recurrent locally advanced or metastatic breast cancer (mBC).

Who cannot join

  • The main exclusion criteria include but are not limited to the following:
  • Uncontrolled or significant cardiovascular disease
  • Has any history of (noninfectious) interstitial lung disease (ILD)/ pneumonitis irrespective of steroid use or has current ILD or suspected ILD
  • Has clinically severe respiratory compromise
  • Has any history of or evidence of any current leptomeningeal disease
  • Has clinically significant corneal disease
Show all 16Show fewer
  • Evidence of ongoing uncontrolled systemic bacterial, fungal, or viral infection
  • HIV infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease
  • Known additional malignancy that is progressing or has required active treatment within the past 3 years
  • Part 1: Evidence of spinal cord compression or brain metastases
  • Part 2: Evidence of spinal cord compression or brain/CNS metastases.
  • Has an active infection requiring systemic therapy
  • Concurrent active HBV and HCV infection
  • Has had major surgical procedure (excluding placement of vascular access) less than 28 days
  • Part1: Arm 3 ONLY
  • Has received prior treatment with tucatinib, lapatinib, or neratinib, or any investigational HER2-targeted tyrosine kinase inhibitors in the locally advanced or metastatic setting

Trial locations and contacts

18 sites in 6 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

18 sites in 6 countries

United States5 sites, 5 recruiting

  • University of Colorado Anschutz Medical Campus ( Site 0057)

    Aurora, Colorado, 80045

    Study Coordinator, 720-848-1030

    Recruiting

  • Dana-Farber Cancer Institute ( Site 0050)

    Boston, Massachusetts, 02215

    Study Coordinator, 877-338-7425

    Recruiting

  • Inova Schar Cancer Institute ( Site 0051)

    Fairfax, Virginia, 22031

    Study Coordinator, 571-472-4724

    Recruiting

  • Prisma Health - Upstate (ITOR)_Edenfield ( Site 0053)

    Greenville, South Carolina, 29605

    Study Coordinator, 864-455-3600

    Recruiting

  • Rutgers Cancer Institute of New Jersey ( Site 0052)

    New Brunswick, New Jersey, 08901

    Study Coordinator, 732-235-2465

    Recruiting

Other trials in United States

Canada4 sites, 4 recruiting

  • Kingston General Hospital ( Site 0061)

    Kingston, Ontario, K7L 2V7

    Study Coordinator, 6135336541

    Recruiting

  • Centre Hospitalier de l'Université de Montréal ( Site 0004)

    Montreal, Quebec, H2X 3E4

    Study Coordinator, (514)890-8000 x20737

    Recruiting

  • Jewish General Hospital ( Site 0003)

    Montreal, Quebec, H3T 1E2

    Study Coordinator, 514-340-8222

    Recruiting

  • Princess Margaret Cancer Centre ( Site 0001)

    Toronto, Ontario, M5G 2M9

    Study Coordinator, 416-946-4501

    Recruiting

Other trials in Canada

Israel3 sites, 3 recruiting

  • Rambam Health Care Campus ( Site 0011)

    Haifa, 3109601

    Study Coordinator, 04-7776234

    Recruiting

  • Rabin Medical Center ( Site 0012)

    Petah Tikva, 4941492

    Study Coordinator, +972-505533121

    Recruiting

  • Sheba Medical Center ( Site 0010)

    Ramat Gan, 5265601

    Study Coordinator, 03-5304498

    Recruiting

Other trials in Israel

United Kingdom3 sites, 3 recruiting

  • The Beatson West of Scotland Cancer Centre ( Site 0043)

    Glasgow, Glasgow City, G12 0YN

    Study Coordinator, +441413017000

    Recruiting

  • University College London Hospital ( Site 0041)

    London, Camden, NW1 2PG

    Study Coordinator, +442034472930

    Recruiting

  • St Bartholomew s Hospital ( Site 0040)

    London, London, City of, EC1A 7BE

    Study Coordinator, +442073777000

    Recruiting

Other trials in United Kingdom

South Korea2 sites, 2 recruiting

  • Seoul National University Hospital ( Site 0030)

    Seoul, 03080

    Study Coordinator, 82-2-2072-0850

    Recruiting

  • Asan Medical Center ( Site 0031)

    Seoul, 05505

    Study Coordinator, +82-2-1688-7575

    Recruiting

Other trials in South Korea

Japan1 site, 1 recruiting

  • Nagoya City University Hospital ( Site 0020)

    Nagoya, Aichi-ken, 467-8602

    Study Coordinator, +81-52-851-5511

    Recruiting

Other trials in Japan

About this study

Official title: HERTHENA-Breast-01: A Phase 1b/2, Multicenter, Open-label, Dose-Finding Study to Evaluate the Safety and Antitumor Activity of Patritumab Deruxtecan in Participants With HER2 Positive Unresectable Locally Advanced Breast Cancer or Metastatic Breast Cancer

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). The goals of this study are to learn:

  • About the safety and how well people tolerate of patritumab deruxtecan
  • How many people have the cancer respond (get smaller or go away) to treatment
Read the detailed description

The following countries will be participating in the trial: Canada, United Kingdom, Israel, Japan, South Korea, and USA.

Being tested
Patritumab deruxtecan, Trastuzumab, Trastuzumab Biosimilar, Pertuzumab, Tucatinib
Medical subject headings
Breast 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

    Patritumab deruxtecan administered via IV infusion

  • TrastuzumabBiological

    Also called Herceptin®

    Trastuzumab administered via IV infusion

  • Trastuzumab BiosimilarBiological

    Also called Trazimera®, Ogivri®, Herzuma®, Ontruzant®

    Trastuzumab biosimilar administered via IV infusion

  • PertuzumabBiological

    Pertuzumab administered via IV infusion

  • TucatinibBiological

    Tucatinib administered as oral tablets

Study groups in NCT06686394
Study groupRoleWhat they receive
Part 1: Patritumab deruxtecan plus trastuzumabExperimentalParticipants receive patritumab deruxtecan intravenous (IV) infusion and trastuzumab or trastuzumab biosimilar IV infusion on Day 1 of each 21-day cycle (every 3 weeks) until disease progression, intolerable toxicity, or investigator decision.
Receives: Biological: Patritumab deruxtecan; Biological: Trastuzumab; Biological: Trastuzumab Biosimilar
Part 1: Patritumab deruxtecan plus pertuzumab and trastuzumabExperimentalParticipants receive patritumab deruxtecan IV infusion, pertuzumab IV infusion, and trastuzumab or trastuzumab biosimilar IV infusion on Day 1 of each 21-day cycle (every 3 weeks) until disease progression, intolerable toxicity, or investigator decision.
Receives: Biological: Patritumab deruxtecan; Biological: Trastuzumab; Biological: Trastuzumab Biosimilar; Biological: Pertuzumab
Part 1: Patritumab deruxtecan plus trastuzumab and tucatinibExperimentalParticipants receive patritumab deruxtecan IV infusion and trastuzumab or trastuzumab biosimilar IV infusion on Day 1 of each 21-day cycle (every 3 weeks), and tucatinib is administered orally twice daily for each 21-day cycle, until disease progression, intolerable toxicity, or investigator decision.
Receives: Biological: Patritumab deruxtecan; Biological: Trastuzumab; Biological: Trastuzumab Biosimilar; Biological: Tucatinib
Part 2: Patritumab deruxtecan plus pertuzumab and trastuzumabExperimentalParticipants receive patritumab deruxtecan IV infusion, pertuzumab IV infusion, and trastuzumab or trastuzumab biosimilar IV infusion on Day 1 of each 21-day cycle (every 3 weeks) until disease progression, intolerable toxicity, or investigator decision.
Receives: Biological: Patritumab deruxtecan; Biological: Trastuzumab; Biological: Trastuzumab Biosimilar; Biological: Pertuzumab

What is being measured

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

  1. Part 1: Number of Participants Experiencing Dose-Limiting Toxicity (DLT)

    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.

    Measured: Up to 21 days

  2. Part 1: Number of Participants with One or More Adverse Events (AEs)

    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.

    Measured: Up to approximately 36 months

  3. Part 1: Number of Participants who Discontinue Study Intervention Due to an AE

    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.

    Measured: Up to approximately 12 months

  4. 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 (RECIST) 1.1. The percentage of participants who experience CR or PR as assessed by Blinded Independent Central Review (BICR)will be presented.

    Measured: Up to approximately 36 months

Secondary outcomes (13)

  1. Part 1: Maximum Plasma Concentration (Cmax) of Patritumab Deruxtecan Antibody-Drug Conjugate (ADC)

    Blood samples collected at designated time points will be used to determine the Cmax of patritumab deruxtecan ADC.

    Measured: At designated time points (up to ~13 months)

  2. Part 1: Trough Concentration (Ctrough) of Patritumab Deruxtecan ADC

    Blood samples collected at designated time points will be used to determine the Ctrough of patritumab deruxtecan ADC.

    Measured: At designated time points (up to ~13 months)

  3. Part 1: Area Under the Plasma Concentration-Time Curve (AUC) of Patritumab Deruxtecan ADC

    Blood samples collected at designated time points will be used to determine the AUC of patritumab deruxtecan ADC.

    Measured: At designated time points (up to ~13 months)

  4. Part 1: Maximum Plasma Concentration (Cmax) of Total Patritumab Deruxtecan Antidrug Antibody (ADA)

    Blood samples collected at designated time points will be used to determine the Cmax of total patritumab deruxtecan ADA.

    Measured: At designated time points (up to ~13 months)

  5. Part 1: Trough Concentration (Ctrough) of Total Patritumab Deruxtecan ADA

    Blood samples collected at designated time points will be used to determine the Ctrough of total patritumab deruxtecan ADA.

    Measured: At designated time points (up to ~13 months)

  6. Part 1: Area Under the Plasma Concentration-Time Curve (AUC) of Total Patritumab Deruxtecan ADA

    Blood samples collected at designated time points will be used to determine the AUC of total patritumab deruxtecan ADA.

    Measured: At designated time points (up to ~13 months)

  7. Part 1: Maximum Plasma Concentration (Cmax) of Patritumab Deruxtecan Free Payload

    Blood samples collected at designated time points will be used to determine the Cmax of patritumab deruxtecan free payload.

    Measured: At designated time points (up to ~13 months)

  8. Part 1: Trough Concentration (Ctrough) of Patritumab Deruxtecan Free Payload

    Blood samples collected at designated time points will be used to determine the Ctrough of patritumab deruxtecan free payload.

    Measured: At designated time points (up to ~13 months)

  9. Part 1: Area Under the Plasma Concentration-Time Curve (AUC) of Patritumab Deruxtecan Free Payload

    Blood samples collected at designated time points will be used to determine the AUC of patritumab deruxtecan free payload.

    Measured: At designated time points (up to ~13 months)

  10. Part 2: Duration of Response (DOR)

    For participants who demonstrate a confirmed 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 RECIST 1.1, DOR is defined as the time from first documented evidence of CR or PR until progressive disease (PD) or death. Per RECIST 1.1, PD is defined as at least a20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of at least 5 mm. The appearance of one or more new lesions is alsoc onsidered PD. DOR as assessed by BICR will be presented.

    Measured: Up to approximately 36 months

  11. Part 2: Progression Free Survival (PFS)

    PFS is defined as the time from first day of study intervention to the first documented progressive disease (PD)or death due to any cause, whichever occurs first as assessed by BICR. Per RECIST 1.1, PD is defined as ≥20% increase in the sum of diameters of target lesions. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions is also considered PD. The appearance of one or more new lesions is also considered PD. PFS as assessed by BICR will be presented.

    Measured: Up to approximately 36 months

  12. Part 2: Number of Participants with One or More AEs

    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.

    Measured: Up to approximately 36 months

  13. Part 2: Number of Participants who Discontinue Study Intervention Due to an AE

    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.

    Measured: Up to approximately 12 months

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted13 Nov 2024
  2. Study start26 Feb 2025
  3. Primary completion2 Aug 2032 (estimated)
  4. Study completion2 Aug 2032 (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
Non-randomised
Intervention model
Sequential
Masking
None (open label)
Enrolment
181 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06686394
Sponsor's protocol ID
1022-009
Other IDs
MK-1022-009, jRCT2041250022, 2026-528266-19, U1111-1346-4321
Status last verified
Oct 2026
First submitted
11 Nov 2024
Last updated
21 Oct 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
Yes: https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Questions about this trial

What is this clinical trial studying?

A Phase 1/2 study testing Patritumab deruxtecan, Trastuzumab and Trastuzumab Biosimilar in people with Breast Neoplasms and Breast Cancer, run by Merck Sharp & Dohme LLC at 18 sites in 6 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 14 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 21 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 18 sites in United States, Canada, Israel, United Kingdom, South Korea and 1 more country. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this combined phase mean?

Phase 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Toll Free Number (1-888-577-8839, Trialsites@msd.com), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Part 1: Number of Participants Experiencing Dose-Limiting Toxicity (DLT) (time frame: Up to 21 days). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06686394.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Oct 2026.

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