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About the Investigational Study Drugs

The investigational combination of drugs involved in this clinical research study are tucatinib,* trastuzumab, and pertuzumab. Tucatinib has been approved by the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA), Swissmedic, Health Canada, and the Therapeutic Goods Administration (TGA) in Australia for those living with HER2-positive breast cancer that has grown, spread to other parts of the body, or can’t be removed by surgery.

You will be given the study drugs in 21-day cycles. This means you’ll take tablets every day during each cycle and receive trastuzumab and pertuzumab on day 1 of each 21-day cycle. On some days, you will need to go to the clinic where the clinical research study is taking place.

*The use of tucatinib described here is experimental. Because of that, not all risks are known before starting a clinical trial.

Why Participate?

If you qualify and decide to participate in the clinical research study, you will help advance medical knowledge about HER2+ metastatic breast cancer.
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Any information you provide will be kept confidential.
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Study Participation and Your Safety

The idea of taking part in a clinical research study might be scary. You should know that participant safety is our number one priority during every stage of the study process. All clinical research studies are carefully supervised, monitored, and documented. Every clinical research study is reviewed and approved by a special group of people called an Institutional Review Board (IRB) or Ethics Committee (EC), which is made up of scientists, nonscientist professionals, and members of the public. They make sure that participants’ rights are protected, and they seek to avoid exposure to unnecessary risks. IRBs and ECs will approve only studies that they think could help answer important medical questions.

For more information about clinical trials, visit

While the study is ongoing, a team of study doctors and nurses at the study site will closely monitor your health. If you have questions or concerns at any point throughout the study, a study staff member is available. The study staff can also tell you about their COVID-19 safety protocols.

There are also risks involved in the HER2CLIMB-05 study, including possible side effects from study treatment. This investigational drug may have little, if any, benefit to you.

Your participation is voluntary, and you are free to withdraw at any time, for any reason. Although others can help you make up your mind, the final decision is yours to make. Your privacy will be maintained throughout the study.

Participants play an important role in clinical trials. It is only through the completion of clinical trials that investigational medications can be evaluated and, if proven safe and effective, approved for a particular use.

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Any information you provide will be kept confidential. question mark

About HER2+ Breast Cancer

Breast cancer develops when cells within the breast begin to grow and divide uncontrollably.1 There are different types of breast cancer that impact how breast cancer presents and how people respond to treatment.1 Both men and women can get breast cancer.2

HER2 is a protein.3 HER2 proteins are receptors on breast cells.4 A normal amount of HER2 is healthy – it helps to control how cells grow, divide, and repair themselves.4 However, having high levels of HER2 can cause the cell to grow out of control.4

If you have breast cancer, your doctor will likely test the levels of HER2 to find out if you're “positive” or “negative.” HER2+ (or HER2-positive) means that the breast cancer cells contain higher levels than normal of HER2.5 HER2+ breast cancers tend to grow and spread faster than other breast cancers.6

Her2 normal cell & Her2+ cancer cellHer2 normal cellHer2+ cancer cell


  1. American Cancer Society. Breast Cancer Facts & Figures 2019-2020. American Cancer Society, Inc. 2019.
  2. Breast cancer in men. Centers for Disease Control and Prevention. Accessed August 30, 2022. https://www.cdc.gov/cancer/breast/men/
  3. Breast cancer HER2 status. American Cancer Society. Revised August 25, 2022. Accessed August 30, 2022. https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-her2-status.html
  4. HER2 status. Breastcancer.org. Updated July 27, 2022. Accessed August 30, 2022. https://www.breastcancer.org/pathology-report/her2-status
  5. Salamon M. Will my HER2-positive breast cancer spread? WebMD. Accessed August 30, 2022. https://www.webmd.com/breast-cancer/her2-positive-spread#:~:text=About%20one%20in%20every%20five,depends%20on%20several%20other%20things
  6. HER2 receptors & cancer cells. WhatHealth. Accessed August 30, 2022. https://www.whathealth.com/breastcancer/her2receptor.html

Study Locations

Locations shown may have changed in some cases. Please call the number listed in the location results to confirm the nearest study site. Talk with a study site member for more information.

Frequently Asked Questions

About the HER2CLIMB-05 Clinical Research Study

The purpose of the HER2CLIMB-05 Clinical Research Study is to explore how well the investigational study drug works at treating HER2+ metastatic breast cancer along with trastuzumab and pertuzumab.
Seagen is performing the HER2CLIMB-05 Clinical Research Study. Seagen is a global biotechnology company that develops and commercializes transformative cancer therapies.
Deciding to participate in a clinical research study is an important and personal decision. Before you agree to participate, the study team will review all aspects of the clinical research study with you. You will be given a document called an Informed Consent Form that provides, in writing, the clinical research study's purpose, assessments, procedures, benefits, risks, and precautions. You will have the opportunity to ask questions and are encouraged to speak with your own physician to decide if taking part is right for you.
Some study-related care and investigational drug costs may be covered. You may be reimbursed for expenses relating to attending study appointments such as travel, as per local regulations. The study staff can give you more information about this.
Yes. There is a chance of receiving a placebo during this study. A placebo looks exactly like tucatinib, but it doesn’t contain any active medicine. A placebo is used in the clinical research study to see if the same effects happen when tucatinib is taken, as when the placebo is taken. All study participants, regardless of whether they receive placebo or tucatinib, will receive trastuzumab and pertuzumab, which they would likely receive if they were not participating in the study.
Yes, the information you provide will not be shared with anyone who is not directly associated with this clinical research study without your permission, except as required by law or as set forth in the Informed Consent Form, the document you would sign before participating in the study.
Yes, your participation in any clinical research study is completely voluntary. If you decide to participate, you can choose to stop taking part at any time and for any reason. Just let the study team know. If you choose to stop taking part, this will not affect your medical care and you will still receive the standard of care treatment. You should talk to your study doctor about leaving the study so that they can schedule a final evaluation.

About Clinical Research Studies

A clinical research study, also known as a clinical trial, is a scientific study that evaluates the safety and effectiveness of a study medication. Qualified doctors, nurses, and other medical professionals are responsible for conducting the study.

It is only through the completion of clinical research studies that study medications can be evaluated and, if proven safe and effective, approved for a particular use. Different regulatory bodies in different countries may provide this approval after a thorough review, such as the US Food and Drug Administration (FDA). Prescription medications in use today were first proven safe and effective during research studies.

In order to ensure that a clinical research study is ethical, and that patients’ rights are protected, Institutional Review Boards (IRBs) or Ethics Committees (ECs) review study protocols.
Only patients who meet all required eligibility criteria for a clinical research study may take part. The study team at the study doctor’s office will review your medical history and current medical status against the eligibility criteria. They will determine if you are eligible to participate in the clinical research study. You may also be asked to provide information from your medical records to help the study team determine whether you may be eligible.

An investigational study drug is a medication that has not been approved by regulatory or health authorities (eg, the US Food and Drug Administration [FDA], European Medicines Agency [EMA], or appropriate regulatory authorities in each country) for prescription use. Before a trial ever allows people to join, it must go through approvals and reviews by organizations and agencies like the FDA as well as scientists, doctors, and community members to make sure it is generally safe and ethical for people to take part.

Tucatinib is approved by the FDA and other regulatory agencies for use in combination with trastuzumab and capecitabine in metastatic HER2+ breast cancer in certain treatment situations. However, it has not been approved in combination with trastuzumab and pertuzumab, which is why it is considered investigational in this clinical research study.

Any information you provide will be kept confidential.
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