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Study on Trastuzumab Deruxtecan, Trastuzumab, and Pertuzumab for Patients with HER2-Positive Unresectable Locally Recurrent or Metastatic Breast Cancer

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical examination is about patients with a type of breast cancer called HER2-positive unresectable locally recurrent or metastatic breast cancer. This means the cancer has returned or spread and cannot be removed with surgery. The study is trying to see how effective a combination of treatments is for this kind of cancer.

The cancer treatment in this study involves two steps. First, patients receive a drug called trastuzumab deruxtecan, which is given as an intravenous infusion. This is used as an initial or induction treatment. After this, the study uses a combination of drugs called Phesgo, which includes two active ingredients: trastuzumab and pertuzumab. Phesgo is given as an injection and is used to maintain the treatment's effects after trastuzumab deruxtecan.

The main purpose of this study is to check how long patients can live without the cancer getting worse after one year and the overall survival at three years. Participants in this study have not received chemotherapy or treatments targeting HER2 for their advanced cancer before. The study aims to provide insights into whether the treatment can help control cancer growth and improve patients’ survival.

The research process

The trial runs in 3 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Induction Treatment

    The initial phase involves the administration of trastuzumab deruxtecan. This medication is given as an intravenous infusion. The specific dosage and frequency will be determined by the healthcare provider based on individual patient needs.

    This phase aims to reduce the size of the tumor and manage the disease effectively. The duration of this treatment will be specified by the healthcare provider.

  2. Step 2

    Maintenance Therapy

    Following the induction treatment, the patient will transition to maintenance therapy with Phesgo, which contains trastuzumab and pertuzumab.

    Phesgo is administered as a solution for injection. The dosage options include 600 mg/600 mg or 1200 mg/600 mg, depending on the patient's specific treatment plan.

    The frequency and duration of this maintenance therapy will be determined by the healthcare provider, aiming to maintain disease control and prevent progression.

  3. Step 3

    Monitoring and Follow-up

    Throughout the trial, regular monitoring will be conducted to assess the patient's response to treatment and manage any side effects.

    This includes routine medical evaluations, imaging tests, and laboratory assessments to ensure the treatment's effectiveness and the patient's safety.

    The healthcare provider will provide specific instructions regarding the schedule and type of follow-up required.

Who can join the trial?

25 criteria

  • The patient must understand the purpose of the study and sign a written informed consent form before starting any study procedures.
  • The patient should not have received any prior chemotherapy or HER2-targeted therapy for advanced disease. However, one prior line of hormone therapy is allowed for metastatic breast cancer (MBC).
  • The patient may have received chemotherapy or HER2-targeted therapy before, as long as there was a gap of at least 12 months between the end of that treatment and the diagnosis of metastatic disease.
  • The patient must have adequate bone marrow and organ function, which includes:
    • White blood cell count greater than 3.0 x 109/L.
    • Absolute neutrophil count (a type of white blood cell) of at least 1.5 x 109/L.
    • Platelet count of at least 100.0 x 109/L.
    • Hemoglobin level of at least 9.0 g/dL.
    • Serum albumin level of at least 2.5 g/dL.
    • Total bilirubin level no more than 1.5 times the upper limit of normal (or 3 times for those with Gilbert's disease).
    • Alkaline phosphatase level no more than 2.5 times the upper limit of normal (or 5 times for those with liver or bone metastases).
    • Aspartate transaminase (AST) and alanine transaminase (ALT) levels no more than 1.5 times the upper limit of normal (or 3 times for those with liver metastases).
    • Creatinine clearance (a measure of kidney function) of at least 50 mL/min.
    • Coagulation tests (blood clotting) within normal limits.
    • Any side effects from previous cancer treatments must have resolved to a mild level, except for hair loss or other effects not considered a safety risk.
    • Women who can become pregnant and are sexually active with a male partner must have a negative pregnancy test before starting the study and agree to use effective birth control during the study and for 7 months after the last treatment.
    • Men who are sexually active with a female partner who can become pregnant must be surgically sterile or use effective birth control during the study and for 4 months after the last dose of T-DXd or 7 months after the last dose of PHESGO.
    • The patient must be available for treatment and follow-up visits.
    • The patient must be 18 years or older at the time of signing the consent form.
    • The patient must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1, which means they are fully active or have some symptoms but do not need bed rest during the day.
    • The patient must have a life expectancy of at least 12 weeks at the time of screening.
    • The patient must have a tumor that overexpresses HER2, confirmed by a designated central lab.
    • The patient must have known estrogen receptor (ER) and progesterone receptor (PgR) status before entering the study.
    • The patient must have unresectable locally recurrent or metastatic disease confirmed by a CT scan or MRI that cannot be removed with surgery for a cure.
    • The patient must have disease that can be measured according to specific criteria (RECIST v.1.1).
    • The patient must provide a recent tumor tissue sample. If no previous sample is available, a new biopsy of an accessible tumor is required before starting the study treatment.

Who cannot join the trial?

5 criteria

  • Patients who have already received chemotherapy or treatment specifically targeting HER2 for advanced breast cancer cannot participate. HER2 is a protein that can affect the growth of cancer cells.
  • Patients with breast cancer that can be surgically removed are not eligible. Unresectable means the cancer cannot be removed with surgery.
  • Patients with breast cancer that has not spread beyond the local area or has not come back after treatment are not eligible. Locally recurrent means the cancer has returned in the same area after treatment.
  • Patients who are not within the specified age range for the study cannot participate. The study is open to certain age groups only.
  • Patients who are part of a vulnerable population, which means they might need special protection or care, are not eligible.
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Investigated drugs

  • Trastuzumab Deruxtecan (T-DXd)

    is a medication used as an initial treatment in this trial. It is designed to target and attack HER2-positive cancer cells, which are a type of breast cancer cell that has higher levels of a protein called HER2. This medication helps to slow down or stop the growth of these cancer cells.

  • PHESGO

    is a combination of two medications, Trastuzumab and Pertuzumab, used as a maintenance therapy in this trial. After the initial treatment with Trastuzumab Deruxtecan, PHESGO is given to help keep the cancer from coming back or growing. It works by continuing to target the HER2 protein on cancer cells, helping to control the disease over a longer period.

What is already known about the treatment

  • Trastuzumab Deruxtecan

    This medication is administered intravenously and is currently being studied in clinical trials for its effectiveness in treating HER2-positive unresectable locally recurrent or metastatic breast cancer. It is an antibody-drug conjugate that targets the HER2 protein on cancer cells, delivering a cytotoxic agent directly to the tumor, which helps to kill the cancer cells. Trastuzumab Deruxtecan is classified as a targeted cancer therapy and is being evaluated for its ability to improve progression-free survival in patients.

  • PHESGO

    This medication is a combination of pertuzumab and trastuzumab, administered via subcutaneous injection. It is used as a maintenance therapy following initial treatment with Trastuzumab Deruxtecan for HER2-positive unresectable locally recurrent or metastatic breast cancer. PHESGO works by targeting the HER2 protein, inhibiting cancer cell growth and survival. It is classified as a monoclonal antibody therapy and is being studied for its potential to enhance overall survival rates in patients.

Investigated diseases

HER2-positive unresectable locally recurrent or metastatic breast cancer – This type of breast cancer is characterized by the overexpression of the HER2 protein, which promotes the growth of cancer cells. It is termed "unresectable" when the cancer cannot be surgically removed, and "locally recurrent" when it returns in the same area after treatment. "Metastatic" indicates that the cancer has spread to other parts of the body. The disease progresses as cancer cells continue to grow and spread, often affecting other organs. Patients with this condition may experience symptoms related to the growth and spread of tumors, such as pain or swelling in affected areas. The progression of the disease can vary widely among individuals, depending on various factors including the biology of the cancer and the patient's overall health.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2023-507306-13-00Protocol codeMEDOPP562Estimated enrolment132 patientsSponsorMedica Scientia Innovation Research S.L.

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