Patritumab Deruxtecan for Breast Cancer

Recruiting at 57 trial locations

Overseen By Toll Free Number

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: Merck Sharp & Dohme LLC

Must be taking: CDK4/6 inhibitors

Must not be taking: PARP inhibitors, Topoisomerase inhibitors

Disqualifiers: BRCA mutation, Visceral crisis, Cardiovascular disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: 3

Duration: 13 months

1000 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores new ways to treat a specific type of breast cancer that is hormone receptor-positive (grows with hormones like estrogen) and HER2-negative (lacks certain growth proteins). It focuses on patients whose cancer cannot be removed by surgery or has spread to other body parts. The main goal is to determine if the experimental drug patritumab deruxtecan helps patients live longer without cancer progression, compared to standard treatments like chemotherapy. Patients whose cancer has worsened after previous hormone and CDK4/6 inhibitor treatments might be suitable for this trial. As a Phase 3 trial, this study represents the final step before FDA approval, offering patients access to potentially groundbreaking treatment.

Do I need to stop my current medications to join the trial?

The trial protocol does not specify if you need to stop your current medications, but you must not have received prior systemic anticancer therapy within 4 weeks before joining. If you were treated with endocrine therapy plus a CDK4/6 inhibitor, at least 2 weeks must have passed since your last dose.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Studies have shown that patritumab deruxtecan, the treatment being tested, is generally safe, with most side effects not being severe. Patients who previously tried this treatment tolerated it well. Some experienced side effects related to the treatment, but these were usually manageable. This information comes from individuals who had already tried many other treatments. Their experience suggests that patritumab deruxtecan could be a safe option for those considering joining this trial. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for breast cancer?

Patritumab deruxtecan is unique because it combines an antibody with a chemotherapy drug to specifically target cancer cells in breast cancer. Most treatments for breast cancer, like paclitaxel or capecitabine, work by attacking rapidly dividing cells in general, which can affect healthy cells too. Patritumab deruxtecan, however, is designed to deliver its cancer-killing payload directly to the cancer cells by binding to specific receptors on their surface, potentially increasing effectiveness and reducing side effects. Researchers are excited about its potential to offer more precise treatment with fewer collateral effects compared to the standard chemotherapy options.

What evidence suggests that patritumab deruxtecan might be an effective treatment for breast cancer?

Research has shown that patritumab deruxtecan, also known as HER3-DXd, may effectively treat certain breast cancers. In this trial, participants will receive patritumab deruxtecan through intravenous infusion every three weeks. Studies found that about 80% of patients experienced tumor reduction with this treatment, suggesting it could help control cancer growth. Patritumab deruxtecan targets cancer cells more precisely. Although more research is needed, these early results are promising for individuals with advanced breast cancer that is hormone receptor-positive and HER2-negative. ^{1 2 4 5 6}

Who Is on the Research Team?

Medical Director

Principal Investigator

Merck Sharp & Dohme LLC

Are You a Good Fit for This Trial?

This trial is for individuals with a specific breast cancer type that's hormone receptor-positive, HER2-negative, and can't be fully removed by surgery or has spread to other body parts. Participants must have already tried endocrine therapy.

Inclusion Criteria

Measurable disease per RECIST 1.1 as assessed by the local site investigator/radiology

My breast cancer is HR+/HER2- and cannot be surgically removed or cured.

My cancer is HR+ and HER2- with evaluable HER3 results from a recent biopsy.

Exclusion Criteria

Severe hypersensitivity (≥Grade 3) to HER3-DXd and/or any of its excipients

Severe hypersensitivity (≥Grade 3) to all the available TPC and/or any of their excipients

My breast cancer can be treated with the goal of curing it.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive patritumab deruxtecan or treatment of physician's choice for up to 13 months

13 months

Every 3 weeks (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

Up to 85 months

What Are the Treatments Tested in This Trial?

Interventions

• Patritumab deruxtecan

Trial Overview The study compares the effectiveness of patritumab deruxtecan (HER3-DXd) against standard chemotherapy drugs like paclitaxel or newer treatments such as trastuzumab deruxtecan in extending life or delaying cancer progression.

How Is the Trial Designed?

Group I: Patritumab Deruxtecan Experimental Treatment 1 Intervention

Participants receive patritumab deruxtecan via intravenous (IV) infusion every 3 weeks (Q3W) for approximately 13 months.

Group II: Treatment of Physician's Choice Active Control 5 Interventions

Participants receive treatment of physician's choice (TPC) for up to 13 months. The TPC may be any of the following options: Paclitaxel (80 mg/m\^2) on Days 1, 8, 15, and 22 of each 4-week cycle; Paclitaxel (90 mg/m\^2) on Days 1, 8, and 15 of each 4-week cycle; Nab-paclitaxel (100 mg/m\^2) on Days 1, 8, and 15 of each 4-week cycle; Capecitabine (1000 mg/m\^2) bid on Days 1 to 14 of each 3-week cycle; Liposomal doxorubicin (50 mg/m\^2) on Day 1 of each 4-week cycle; or trastuzumab deruxtecan (T-DXd) (5.4 mg/kg) Q3W.

Who Is Running the Clinical Trial?

Merck Sharp & Dohme LLC

Lead Sponsor

Trials

4,096

Recruited

5,232,000+

Chirfi Guindo

Merck Sharp & Dohme LLC

Chief Marketing Officer since 2022

Degree in Engineering from Ecole Centrale de Paris, MBA from New York University Stern School of Business

Robert M. Davis

Merck Sharp & Dohme LLC

Chief Executive Officer since 2021

JD from Northwestern University Pritzker School of Law, MBA from Northwestern University Kellogg Graduate School of Management, Bachelor's in Finance from Miami University

Daiichi Sankyo

Industry Sponsor

Trials

443

Recruited

493,000+

Hiroyuki Okuzawa

Daiichi Sankyo

Chief Executive Officer

Degree in Social Sciences from Hitotsubashi University

Yuki Abe

Daiichi Sankyo

Chief Medical Officer since 2023

MD

Citations

1. nature.com nature.com/articles/s41591-025-03885-3

Patritumab deruxtecan in HR+HER2− advanced breast ... Among the six patients with available data on ILD duration, two cases resolved within approximately 3 weeks, two cases within 1 month and two ...

2. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/40908353/

Patritumab deruxtecan in HR+HER2- advanced breast ... Antibody-drug conjugates have shown impressive clinical outcomes, particularly in metastatic breast cancer, but biomarkers to predict response

3. ascopubs.org ascopubs.org/doi/10.1200/JCO.23.00882

Patritumab Deruxtecan (HER3-DXd), a Human Epidermal ... Most patients (80.0%), across clinical subtypes, experienced a reduction in the best percentage change in tumor size from baseline (Fig 2). In ...

4. daiichisankyo.us daiichisankyo.us/press-releases/-/article/patritumab-deruxtecan-continues-to-show-encouraging-clinical-activity-in-distinct-patient-populations-with-metastatic-lung-and-breast-cancer-in-update

Patritumab Deruxtecan Continues to Show Encouraging ... “These data support the further evaluation of patritumab deruxtecan as a potential treatment option for breast cancer and learning more about ...

5. merck.com merck.com/news/herthena-breast04-phase-3-trial-of-patritumab-deruxtecan-initiated-in-patients-with-metastatic-hormone-receptor-positive-her2-negative-breast-cancer-previously-treated-with-endocrine-therapy/

HERTHENA-Breast04 Phase 3 Trial of Patritumab ... Patients with HR positive, HER2 negative metastatic breast cancer experience poor outcomes if they progress following initial treatment, ...

6. daiichisankyo.com daiichisankyo.com/files/news/pressrelease/pdf/202206/20220603_E.pdf

breast cancer “Results from this trial show that patritumab deruxtecan produces clinically meaningful and durable antitumor activity in patients and further ...