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Study of Pembrolizumab and Olaparib for Patients with Advanced HER2 Negative Breast Cancer and Specific Genetic Mutations

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 trial is focused on studying a type of breast cancer known as HER2-negative breast cancer. This type of cancer does not have high levels of a protein called HER2, which can promote the growth of cancer cells. The study is specifically looking at patients whose cancer cannot be removed by surgery or has spread to other parts of the body, known as metastatic breast cancer. Additionally, these patients have certain genetic changes, or mutations, in genes such as BRCA1 or BRCA2, which are known to increase the risk of breast cancer. Other genes being studied include ATM, BARD1, CHEK2, FANCC, PALB2, RAD51C, RAD51D, SLX4, and XRCC2, as well as a condition called homologous recombination deficiency, which affects the way cells repair DNA.

The trial is testing a combination of two treatments: pembrolizumab and olaparib. Pembrolizumab is a type of medicine called a PD-1 inhibitor, which helps the immune system recognize and attack cancer cells. Olaparib is a PARP inhibitor, which helps prevent cancer cells from repairing themselves, leading to their death. The purpose of the study is to see how effective this combination is in treating the cancer. Participants will receive these treatments over a period of 27 weeks, and their response to the treatment will be monitored.

Throughout the study, researchers will observe how well the cancer responds to the treatment, how long the response lasts, and how long patients live without the cancer getting worse. They will also monitor any side effects or serious health issues that may occur. This information will help determine if the combination of pembrolizumab and olaparib is a beneficial treatment option for patients with this specific type of breast cancer.

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

    Initial visit

    Upon joining the study, you will attend an initial visit where you will receive detailed information about the trial. This includes understanding the purpose, procedures, and potential risks and benefits.

    You will be asked to provide written informed consent, confirming your willingness to participate in the study.

  2. Step 2

    Screening tests

    You will undergo a series of screening tests to confirm eligibility. These tests may include blood tests, imaging scans, and a biopsy of the tumor.

    A negative pregnancy test is required for female participants within 72 hours before the first dose of trial treatment.

  3. Step 3

    Treatment initiation

    Once eligibility is confirmed, you will begin treatment with two medications: pembrolizumab and olaparib.

    Pembrolizumab will be administered through an infusion. The frequency and dosage will be explained to you by the medical team.

    Olaparib will be taken orally. The specific dosage and frequency will be provided by the medical team.

  4. Step 4

    Ongoing treatment and monitoring

    Throughout the trial, you will continue to receive the medications as prescribed. Regular monitoring will be conducted to assess your response to the treatment.

    You will have scheduled visits for physical exams, blood tests, and imaging scans to track the progress of the treatment.

  5. Step 5

    End of treatment

    The treatment phase is expected to last up to 27 weeks, during which your response to the medications will be evaluated.

    After completing the treatment, you will have a final assessment to determine the overall response and any changes in your condition.

  6. Step 6

    Follow-up

    Following the end of treatment, you will enter a follow-up period. This involves periodic check-ups to monitor your health and any long-term effects of the treatment.

    The follow-up period will help gather information on the duration of response and overall survival.

Who can join the trial?

17 criteria

  • The participant or their legally acceptable representative must provide written informed consent.
  • Participants with hormone receptor positive breast cancer must have already tried and not benefited from previous combination therapy of CDK4/6 inhibitors with endocrine treatment.
  • The participant must have a measurable disease based on RECIST v1.1, which is a standard way to measure how well a cancer treatment works.
  • The participant must provide a recent biopsy of a tumor lesion, taken within 12 months before joining the study. A biopsy is a small sample of tissue taken from the body for testing.
  • The participant must have an 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.
  • Female participants must have a negative pregnancy test within 72 hours before the first dose of trial treatment and must not be breastfeeding.
  • Female participants who can have children must agree to use effective birth control during the study and for 120 days after the last dose of study medication.
  • Male participants must agree to use effective birth control during the study and for 120 days after the last dose of study medication.
  • The participant must have adequate organ function, meaning their organs are working well enough to participate in the study.
  • Male and Female participants must be at least 18 years old at the time of signing the informed consent and must be willing to follow the study procedures.
  • The participant must have histologically confirmed metastatic or advanced, unresectable HER2 negative breast cancer, which means the cancer has spread and cannot be removed by surgery, and it is not eligible for curative treatment.
  • Cohort 1: The participant must have a germline mutation in BRCA1 or BRCA2 that is predicted to be harmful, regardless of HRD status. A germline mutation is a genetic change that can be passed from parents to children.
  • Cohort 2: The participant must have a germline mutation in ATM, BARD1, CHEK2, FANCC, PALB2, RAD51C, RAD51D, SLX4, or XRCC2 that is predicted to be harmful, regardless of HRD status.
  • Cohort 3: The participant must have high HRD status and no germline mutation in the genes mentioned for cohort 1 or cohort 2. HRD status refers to a deficiency in the way cells repair DNA.
  • Cohort 3: The participant must provide FFPE tumor material for further validation of HRD status. FFPE stands for formalin-fixed, paraffin-embedded, which is a method of preserving tissue samples.
  • Cohorts 2 and 3: The participant must have been treated with first-line chemotherapy if this is the standard care for their therapy situation.
  • Prior platinum treatment in the (neo)adjuvant setting is allowed as long as 12 months have passed since the last dose before joining the study. (Neo)adjuvant treatment is additional cancer treatment given before or after the main treatment.

Who cannot join the trial?

4 criteria

  • Patients who do not have unresectable or metastatic HER2 negative breast cancer.
    • Unresectable means the cancer cannot be removed with surgery.
    • Metastatic means the cancer has spread to other parts of the body.
    • Patients who do not have a deleterious germline mutation in specific genes.
      • Deleterious germline mutation refers to harmful changes in genes that are inherited from parents and can increase the risk of cancer.
      • Patients who do not have a homologous recombination deficiency.
        • Homologous recombination deficiency is a condition where the body cannot effectively repair certain types of DNA damage, which can lead to cancer.
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Investigated drugs

  • Pembrolizumab

    is a type of medication known as an immunotherapy. It works by helping your immune system fight cancer cells. In this trial, pembrolizumab is used to treat patients with a specific type of breast cancer that cannot be removed by surgery or has spread to other parts of the body. The goal is to see if pembrolizumab can help shrink the cancer or stop it from growing.

  • Olaparib

    is a medication that targets cancer cells with certain genetic mutations. It works by blocking a protein that cancer cells need to repair themselves, which can lead to the death of these cells. In this trial, olaparib is used alongside pembrolizumab to treat patients with breast cancer who have specific genetic mutations. The aim is to determine if the combination of these two medications is effective in treating the cancer.

What is already known about the treatment

  • Pembrolizumab

    Pembrolizumab is administered as an intravenous infusion, meaning it is given directly into the bloodstream through a vein. It is currently being studied in clinical trials for its effectiveness in treating certain types of breast cancer that cannot be surgically removed or have spread to other parts of the body. The main therapeutic use of pembrolizumab is to help the immune system recognize and attack cancer cells. It works by blocking a specific protein on immune cells, allowing them to better detect and destroy cancer cells. Pembrolizumab is classified as an immune checkpoint inhibitor, a type of drug that helps the immune system fight cancer.

  • Olaparib

    Olaparib is taken orally in the form of tablets, which means it is swallowed and absorbed through the digestive system. It is being researched for its potential to treat breast cancer in patients with specific genetic mutations that affect DNA repair. The primary therapeutic indication for olaparib is to target cancer cells with these mutations, preventing them from repairing their DNA and causing them to die. At the molecular level, olaparib inhibits a protein called PARP, which is involved in DNA repair processes. It is classified as a PARP inhibitor, a type of medication that targets cancer cells with defective DNA repair mechanisms.

Investigated diseases

HER2-negative breast cancer with homologous recombination deficiency – This type of breast cancer lacks the human epidermal growth factor receptor 2 (HER2) protein, which is often involved in the growth of cancer cells. It is characterized by a deficiency in the homologous recombination repair pathway, which is crucial for repairing DNA double-strand breaks. The disease can progress from localized tumors to more advanced stages, where it becomes unresectable or metastatic, meaning it cannot be surgically removed and may spread to other parts of the body. The presence of specific genetic mutations, such as those in BRCA1/2, ATM, and other related genes, can influence the progression and behavior of the cancer. As the disease advances, it may lead to increased tumor size and the involvement of additional tissues or organs. The progression is often monitored through imaging and clinical evaluations to assess changes in tumor size and spread.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519350-37-00Protocol codeIFG-05-2019Estimated enrolment89 patientsSponsorInstitut fuer Frauengesundheit GmbH

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