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Study of Tucatinib, Trastuzumab, and Pertuzumab for Patients with Advanced or Metastatic HER2+ Breast Cancer

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What is this trial about?

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

This clinical trial is focused on studying a type of breast cancer known as HER2-positive breast cancer, which is a form of cancer that has high levels of a protein called HER2. The study is investigating the effectiveness of a treatment combination that includes the medications Tucatinib, Trastuzumab, and Pertuzumab. These medications are used as maintenance therapy, which means they are given to help keep the cancer from coming back or getting worse after initial treatment. The trial will compare the effects of this combination with a placebo, which is a substance with no active medication.

The purpose of the study is to see how well the treatment works in preventing the cancer from progressing, which means getting worse or spreading. Participants in the study will receive either the combination of medications or a placebo, and their health will be monitored over time. The study will involve regular check-ups and assessments to track the progress of the disease and any side effects of the treatment. The trial aims to provide more information on how effective this treatment is in managing advanced or metastatic HER2-positive breast cancer.

Throughout the study, participants will undergo various tests and evaluations, including imaging tests like MRI to check for any changes in the brain, as some patients may have brain metastases, which are cancer cells that have spread to the brain. The study will also look at the overall survival of participants, which is the length of time they live after starting the study, and their quality of life during the treatment. The trial is expected to continue for several years to gather enough data to determine the effectiveness of the treatment.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria, including the type of breast cancer and previous treatments received.

    The study focuses on individuals with advanced or metastatic HER2+ breast cancer.

  2. Step 2

    Randomization

    Participants are randomly assigned to receive either the study medication or a placebo.

    This process ensures that the study results are unbiased and reliable.

  3. Step 3

    Treatment administration

    The treatment involves a combination of medications: trastuzumab, pertuzumab, and tucatinib or a placebo.

    Trastuzumab and pertuzumab are administered as a solution for injection.

    Tucatinib is provided in the form of film-coated tablets, available in 50 mg and 150 mg dosages, taken orally.

  4. Step 4

    Treatment schedule

    The treatment is administered as maintenance therapy following initial induction therapy.

    Participants receive the medications according to a schedule determined by the study protocol.

  5. Step 5

    Monitoring and assessments

    Regular monitoring is conducted to assess the progression of the disease and the participant's response to the treatment.

    Assessments include imaging tests and evaluations based on specific criteria to measure disease progression.

  6. Step 6

    End of study participation

    Participation in the study continues until disease progression or other criteria for discontinuation are met.

    The study aims to compare progression-free survival and overall survival between the treatment groups.

Who can join the trial?

10 criteria

  • The patient must have a type of breast cancer called HER2+, which is confirmed by specific tests. These tests look for certain proteins in the cancer cells.
  • The cancer must be unresectable (cannot be removed by surgery) and either locally advanced or has spread to other parts of the body (metastatic).
  • If the cancer has come back after previous treatment, the patient must have been free from certain treatments (trastuzumab and pertuzumab) for at least 6 months.
  • The patient must have received 4-8 cycles of specific pre-study treatments (trastuzumab, pertuzumab, and taxane) for advanced breast cancer and must not show signs of the cancer getting worse after these treatments.
  • The patient must know their hormone receptor status, which means whether the cancer cells have certain hormone receptors or not.
  • The patient must have an ECOG Performance Status of 0 or 1, which means they are fully active or have some symptoms but can still do light work.
  • Regarding the brain, based on a special brain scan (MRI), the patient may have no brain metastases, untreated brain metastases that are not causing symptoms, or previously treated brain metastases that are not causing symptoms and have not gotten worse.
  • The patient must be within certain age ranges, which are typically adult age groups.
  • Both male and female patients can participate.
  • The study may include patients who are considered part of a vulnerable population.

Who cannot join the trial?

9 criteria

  • Patients with other types of cancer that are not **HER2+ breast cancer** cannot participate. **HER2+ breast cancer** is a type of breast cancer that has a protein called HER2 on the surface of its cells.
  • Patients who have had surgery to remove the cancer cannot participate. **Unresectable** means the cancer cannot be removed by surgery.
  • Patients who have cancer that has spread to other parts of the body, known as **metastatic cancer**, cannot participate.
  • Patients who have cancer that is only in one place and has not spread, known as **locally-advanced cancer**, cannot participate.
  • Patients who are not within the specified age range for the study cannot participate. The age range is not specified here, but it is important for eligibility.
  • Patients who are not able to follow the study procedures or who have other health conditions that might interfere with the study cannot participate.
  • Patients who are pregnant or breastfeeding cannot participate.
  • Patients who have participated in another clinical trial recently may not be eligible.
  • Patients who have certain medical conditions or are taking medications that could affect the study results cannot participate.
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Investigated drugs

  • Tucatinib

    is a medication used in this trial to treat metastatic HER2-positive breast cancer. It works by blocking certain proteins that help cancer cells grow. In this study, it is being tested to see if it can help stop the cancer from getting worse when used with other treatments.

  • Trastuzumab

    is a therapy used to treat HER2-positive breast cancer. It targets the HER2 protein on cancer cells, helping to slow or stop their growth. In this trial, it is used in combination with other medications to see if it can improve outcomes for patients.

  • Pertuzumab

    is another medication used to treat HER2-positive breast cancer. It works by attaching to the HER2 protein and preventing cancer cells from growing. In this study, it is combined with other treatments to evaluate its effectiveness in maintaining cancer control.

What is already known about the treatment

  • Tucatinib

    Tucatinib is administered orally in tablet form. It is currently being studied in clinical trials for its effectiveness in treating HER2-positive breast cancer that is either locally advanced and cannot be surgically removed or has spread to other parts of the body. Tucatinib works by specifically inhibiting the HER2 protein, which is involved in the growth and spread of cancer cells. It belongs to the pharmacological class of tyrosine kinase inhibitors.

  • Trastuzumab

    Trastuzumab is given through intravenous infusion. It is an established treatment for HER2-positive breast cancer, used in both early and advanced stages of the disease. The medication targets the HER2 protein on cancer cells, helping to stop their growth and spread. Trastuzumab is classified as a monoclonal antibody.

  • Pertuzumab

    Pertuzumab is administered via intravenous infusion. It is approved for use in combination with other medications for the treatment of HER2-positive breast cancer, particularly in advanced cases. Pertuzumab works by binding to the HER2 protein, preventing cancer cells from growing and dividing. It is also a monoclonal antibody, similar to trastuzumab.

Investigated diseases

Unresectable Locally-Advanced or Metastatic HER2+ Breast Cancer – This is a type of breast cancer characterized by the overexpression of the HER2 protein, which promotes the growth of cancer cells. In its unresectable form, the cancer cannot be removed completely through surgery. When it is locally advanced, the cancer has spread beyond the breast to nearby tissues or lymph nodes but not to distant organs. In the metastatic stage, the cancer has spread to other parts of the body, such as the bones, liver, or lungs. The disease progresses as cancer cells continue to grow and spread, often leading to the involvement of multiple organs. The progression can vary significantly among individuals, influenced by factors like the cancer's biology and the patient's overall health.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-503826-37-00Protocol codeSGNTUC-028Estimated enrolment713 patientsSponsorSeagen Inc.

sourced from the EU Clinical Trials Register and site verification

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