T-DXd +/− Pertuzumab for Breast Cancer

Not currently recruiting at 318 trial locations

Overseen By AZ Breast Cancer Study Navigators

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: AstraZeneca

Disqualifiers: Substance abuse, Spinal cord compression, ILD, 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: Unknown

Duration: Up to 60 months

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests a new treatment for individuals with HER2-positive breast cancer that has metastasized. It examines the effectiveness of trastuzumab deruxtecan (T-DXd), alone or with pertuzumab (Perjeta), compared to the standard treatment. Individuals recently diagnosed with advanced HER2-positive breast cancer who have not yet received chemotherapy or HER2-targeted therapy may qualify for this trial. The researchers aim to determine if these new treatment options are safe and effective as a first-choice treatment in this context. As a Phase 3 trial, this study represents the final step before FDA approval, offering participants the opportunity to contribute to potentially groundbreaking advancements in cancer treatment.

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

The trial protocol does not specify if you need to stop taking your current medications. However, it does mention that participants should not have had prior chemotherapy or HER2-targeted therapy for advanced or metastatic breast cancer, except for one previous line of endocrine therapy.

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

Research has shown that trastuzumab deruxtecan, or T-DXd, is generally safe and manageable for breast cancer patients. Studies found that although some patients experienced a decrease in a type of white blood cell that helps fight infections, the treatment's overall safety was acceptable. Many patients tolerated the treatment well.

When combined with another drug called pertuzumab, trastuzumab deruxtecan produced promising results. Trials demonstrated that this combination was effective, with consistent safety across different patient groups. No major unexpected side effects were reported.

In clinical trials, the treatment has reached a stage indicating it is well-tolerated by most patients. While some side effects can occur, they are usually manageable. Patients should always discuss any concerns with their healthcare providers. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about these treatments because Trastuzumab Deruxtecan (T-DXd) brings a fresh approach to fighting breast cancer. Unlike standard treatments that use traditional chemotherapy drugs like taxanes, T-DXd is an antibody-drug conjugate. This means it combines an antibody with a chemotherapy drug, specifically targeting cancer cells while sparing more healthy cells. This targeted mechanism is promising for potentially reducing side effects and increasing effectiveness, which is why researchers are eager to explore its potential impact. Furthermore, combining T-DXd with pertuzumab or using it with a placebo offers a new dynamic in treatment strategies, potentially paving the way for more personalized and efficient cancer therapies.

What evidence suggests that this trial's treatments could be effective for HER2-positive breast cancer?

In previous studies, trastuzumab deruxtecan (T-DXd) showed promising results for HER2-positive breast cancer. The treatment reduced the risk of death by 31%, and patients lived without their cancer worsening for an average of 15 months. In this trial, some participants will receive T-DXd alone, while others will receive T-DXd combined with pertuzumab. Past research demonstrated that combining T-DXd with pertuzumab was even more effective, lowering the risk of cancer worsening or causing death by 44% compared to the usual treatment. This combination can delay cancer growth longer than current standard options. These findings suggest that T-DXd, with or without pertuzumab, could effectively treat HER2-positive metastatic breast cancer. ^{5 6 7 8 9}

Are You a Good Fit for This Trial?

This trial is for adults over 18 with HER2-positive metastatic breast cancer. They should have good organ and bone marrow function, an ECOG performance status of 0 or 1, and no prior advanced/metastatic breast cancer treatment except possibly one line of endocrine therapy. Prior neo-adjuvant or adjuvant treatments are okay if it's been over 6 months.

Inclusion Criteria

My organs and bone marrow are functioning well.

My breast cancer is confirmed to be HER2-positive.

I haven't had chemo or HER2 therapy for advanced breast cancer, but may have had one hormone treatment.

Exclusion Criteria

Any substance abuse or other medical conditions that, in the investigator's opinion, may interfere with subject's participation or study results

I have or had lung inflammation that's been confirmed or can't be ruled out.

You have been part of a previous study for trastuzumab deruxtecan, no matter which treatment you received.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive trastuzumab deruxtecan, alone or with pertuzumab, or standard of care treatment

Up to 60 months

Regular visits as per treatment protocol

Follow-up

Participants are monitored for safety and effectiveness after treatment

Up to 60 months

Long-term follow-up

Participants are monitored for overall survival and progression-free survival

Up to 104 months

What Are the Treatments Tested in This Trial?

Interventions

• Pertuzumab
• Trastuzumab
• Trastuzumab Deruxtecan

Trial Overview The study tests the effectiveness and safety of Trastuzumab Deruxtecan (T-DXd), alone or with Pertuzumab, compared to a Taxane-based regimen including Trastuzumab and Pertuzumab as first-line treatments for metastatic HER2-positive breast cancer.

How Is the Trial Designed?

Group I: Arm B Experimental Treatment 2 Interventions

Trastuzumab deruxtecan (T-DXd) plus pertuzumab

Group II: Arm A Experimental Treatment 2 Interventions

Trastuzumab deruxtecan (T-DXd) plus pertuzumab-matching placebo

Group III: Arm C Active Control 3 Interventions

Standard of care (Taxane (paclitaxel or docetaxel), trastuzumab, and pertuzumab)

Pertuzumab is already approved in European Union, United States, Canada, Japan for the following indications:

Approved in European Union as Perjeta for:

• Early breast cancer
• Metastatic breast cancer

Approved in United States as Perjeta for:

• Early breast cancer
• Metastatic breast cancer

Approved in Canada as Perjeta for:

• Early breast cancer
• Metastatic breast cancer

Approved in Japan as Perjeta for:

• Early breast cancer
• Metastatic breast cancer

Who Is Running the Clinical Trial?

AstraZeneca

Lead Sponsor

Trials

4,491

Recruited

290,540,000+

Sir Pascal Soriot

AstraZeneca

Chief Executive Officer since 2012

Veterinary Medicine from École nationale vétérinaire d'Alfort, MBA from HEC Paris

Dr. Cristian Massacesi

AstraZeneca

Chief Medical Officer since 2021

MD from Marche Polytechnic University, Oncology training at Royal Marsden Hospital, Kaplan Comprehensive Cancer Center, and European Institute of Oncology

Pascal Soriot

AstraZeneca

Chief Executive Officer since 2012

Veterinary Medicine from École nationale vétérinaire d'Alfort, MBA from HEC Paris

Cristian Massacesi

AstraZeneca

Chief Medical Officer since 2021

MD from Marche Polytechnic University, Medical Oncology training at Royal Marsden Hospital, Kaplan Comprehensive Cancer Center, and European Institute of Oncology

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

Daiichi Sankyo, Inc.

Industry Sponsor

Trials

390

Recruited

442,000+

Yuki Abe

Daiichi Sankyo, Inc.

Chief Medical Officer since 2022

MD

Hiroyuki Okuzawa

Daiichi Sankyo, Inc.

Chief Executive Officer

Degree in Social Sciences from Hitotsubashi University

Published Research Related to This Trial

A comprehensive analysis of 14,707 adverse events related to pertuzumab from the FDA Adverse Event Reporting System revealed significant safety concerns, including potential risks of myelosuppression, cardiotoxicity, and other serious conditions occurring in 12 organ systems.

Most adverse events, particularly cardiac-related issues, were reported within the first month of therapy, highlighting the need for careful monitoring and preparedness for emergency interventions, especially in elderly patients and those with pre-existing cardiovascular conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A disproportionality analysis of adverse events associated to pertuzumab in the FDA Adverse Event Reporting System (FAERS). Zou, SP., Yang, HY., Ouyang, ML., et al.[2023]

Trastuzumab deruxtecan (Enhertu®) has been shown to significantly improve progression-free survival in adults with unresectable or metastatic HER2-positive breast cancer compared to the previous standard treatment, trastuzumab emtansine, in a pivotal phase 3 trial.

The treatment has a generally manageable safety profile, although it is associated with common adverse events like hematological and gastrointestinal disorders, and requires careful monitoring for interstitial lung disease (ILD)/pneumonitis.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Trastuzumab Deruxtecan: A Review in Unresectable or Metastatic HER2-Positive Breast Cancer. Nie, T., Blair, HA.[2023]

Trastuzumab deruxtecan (T-DXd) is a promising new antibody-drug conjugate that has been approved for treating HER2-positive metastatic breast cancer and gastric cancer, showing potential for use in other solid tumors as well.

T-DXd is expected to become the standard second-line treatment for HER2-positive metastatic breast cancer and may also benefit patients with hormone receptor-positive and triple-negative breast cancer that express low levels of HER2.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Trastuzumab deruxtecan in HER2-positive metastatic breast cancer and beyond. Perez, J., Garrigós, L., Gion, M., et al.[2022]

Trastuzumab deruxtecan (ENHERTU®) is an innovative treatment that combines an antibody targeting HER2 with a DNA topoisomerase I inhibitor, specifically designed for HER2-expressing solid tumors, including various types of cancer.

It received accelerated approval in the USA based on the promising results from the phase 2 DESTINY-Breast01 trial, which focused on patients with advanced HER2-positive breast cancer who had already undergone multiple treatments.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Trastuzumab Deruxtecan: First Approval. Keam, SJ.[2020]

Trastuzumab deruxtecan (T-DXd) showed promising antitumor activity in patients with advanced HER2-low breast cancer, achieving a 37% objective response rate in a study of 54 patients who had undergone a median of 7.5 prior therapies.

While T-DXd demonstrated efficacy, it also presented significant safety concerns, with 98% of patients experiencing treatment-emergent adverse events, including severe cases of interstitial lung disease (ILD) that led to fatalities, highlighting the need for careful monitoring.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Antitumor Activity and Safety of Trastuzumab Deruxtecan in Patients With HER2-Low-Expressing Advanced Breast Cancer: Results From a Phase Ib Study. Modi, S., Park, H., Murthy, RK., et al.[2021]

In an expanded-access study involving 64 patients with HER2-positive gastric or gastroesophageal junction adenocarcinomas, trastuzumab deruxtecan (T-DXd) was administered safely, with no new safety concerns identified prior to its marketing approval in Japan.

Serious adverse events (SAEs) were reported in 26.6% of patients, with febrile neutropenia being the most common; however, drug-related SAEs led to death in only one patient, indicating a manageable safety profile for T-DXd.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Trastuzumab deruxtecan in patients with locally advanced or metastatic HER2-positive gastric cancer: a multicenter, open-label, expanded-access study. Shitara, K., Yamaguchi, K., Muro, K., et al.[2023]

A study involving 808 patients with HER-2 positive breast cancer showed that adding pertuzumab to trastuzumab and docetaxel significantly improved overall survival, with a 3-year survival rate increase of 10% to 15%.

While pertuzumab did not worsen cardiac toxicity in patients with low cardiovascular risk, it was associated with increased side effects such as severe diarrhea and skin disorders, indicating the need for careful monitoring.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Pertuzumab. Promising for some women with metastatic breast cancer, but more assessment needed. [2016]

In a phase II study involving 267 patients with HER2-expressing solid tumors, trastuzumab deruxtecan (T-DXd) showed an overall objective response rate (ORR) of 37.1%, with a median duration of response of 11.3 months, indicating its efficacy in treating these cancers.

Patients with central HER2 IHC 3+ expression had even better outcomes, with an ORR of 61.3% and a median overall survival of 21.1 months, highlighting T-DXd's potential as a targeted therapy for HER2-positive tumors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy and Safety of Trastuzumab Deruxtecan in Patients With HER2-Expressing Solid Tumors: Primary Results From the DESTINY-PanTumor02 Phase II Trial. Meric-Bernstam, F., Makker, V., Oaknin, A., et al.[2023]

Trastuzumab deruxtecan (T-DXd) is an antibody-drug conjugate that combines an anti-HER2 antibody with a topoisomerase I inhibitor, showing a stable drug-to-antibody ratio in vivo compared to other similar drugs.

In a study involving monkeys, the concentrations of the drug and antibody decreased over time after administration, with the drug-to-antibody ratio dropping to about 2.5 over 21 days, indicating a gradual release of the drug.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transition of average drug-to-antibody ratio of trastuzumab deruxtecan in systemic circulation in monkeys using a hybrid affinity capture liquid chromatography-tandem mass spectrometry. Habara, H., Okamoto, H., Nagai, Y., et al.[2023]

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC12479221/

Efficacy of Trastuzumab Deruxtecan in HER2-Positive and ... Among the 98 patients, the median PFS was 15.0 months. The ORR, DCR, and CBR were 48.0%, 69.4%, and 41.8%, respectively. HER2-positive patients ...

2. enhertuhcp.com enhertuhcp.com/en/breast/efficacy/efficacy-data

Efficacy data | ENHERTU® (fam-trastuzumab deruxtecan-nxki) Median time to first onset was 5.5 months (range: 0.9 to 31.5). Fatal outcomes due to ILD and/or pneumonitis occurred in 0.9% of patients treated with ENHERTU.

3. nature.com nature.com/articles/s41591-025-03981-4

Trastuzumab deruxtecan in HER2-low metastatic breast ... Patients treated with T-DXd had a 31% reduction in the risk of death in both the overall and HR+ cohorts and a 42% reduction in risk of death in ...

4. astrazeneca-us.com astrazeneca-us.com/media/press-releases/2025/ENHERTU-fam-trastuzumab-deruxtecan-nxki-demonstrated-highly-statistically-significant-and-clinically-meaningful-improvement-in-invasive-disease-free-survival-vs-T-DM1-in-DESTINY-Breast05-Phase-III-trial-in-patients-with-high-risk-early-breast-cancer-following-neoadjuvant-therapy.html

ENHERTU® (fam-trastuzumab deruxtecan-nxki) ... ENHERTU® (fam-trastuzumab deruxtecan-nxki) demonstrated highly statistically significant and clinically meaningful improvement in invasive ...

5. esmoopen.com esmoopen.com/article/S2059-7029(25)01199-8/fulltext

Outcomes with trastuzumab deruxtecan by biomarker ... In a large (n = 1490) real-world dataset, T-DXd exhibited favorable activity for metastatic breast cancer (MBC).

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC11178646/

Safety profile of trastuzumab deruxtecan in advanced breast ... The percentage of patients with a confirmed objective response among all patients was 52.3% (95% CI 47.1–57.4) in the T-DXd arm and 16.3% (95% CI: 11.3 to 22.5) ...

7. enhertuhcp.com enhertuhcp.com/en/breast/safety

Safety Data | ENHERTU® (fam-trastuzumab deruxtecan-nxki) In patients with metastatic breast cancer and other solid tumors treated with ENHERTU 5.4 mg/kg, a decrease in neutrophil count was reported in 65% of patients.

8. sciencedirect.com sciencedirect.com/science/article/pii/S2949820124000730

Real-world safety and effectiveness data of trastuzumab ... Real-world safety and effectiveness data of trastuzumab deruxtecan and sacituzumab govitecan in breast cancer: a Hellenic Cooperative Oncology Group study.

9. ascopubs.org ascopubs.org/doi/10.1200/JCO.2025.43.16_suppl.e13023

Efficacy and safety of trastuzumab deruxtecan in HER2+ ... Our study supports the efficacy and safety of T-DXd in India in a real-world clinical setting with results being consistent across published literature.