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Study on the Safety and Effectiveness of Vepdegestrant and PF-07220060 for Adults with ER+/HER2- Advanced or Metastatic Breast Cancer

Fast replyInvestigationalNo 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 ER-positive/HER2-negative advanced or metastatic breast cancer. This type of cancer is characterized by the presence of estrogen receptors and the absence of human epidermal growth factor receptor 2. The study involves two medications: Vepdegestrant (ARV-471/PF-07850327) and PF-07220060. Vepdegestrant is an oral medication designed to target and break down specific proteins in cancer cells, while PF-07220060 is another oral medication being tested in combination with Vepdegestrant.

The purpose of the study is to evaluate the safety and effectiveness of these medications when used together. Participants will take the medications in the form of film-coated tablets. The study will be conducted in two phases. In the first phase, the focus will be on assessing how well participants tolerate the combination of medications and determining the best doses to use. In the second phase, the study will look at how effective the combination is in treating the cancer.

Throughout the study, participants will be monitored for any side effects and changes in their condition. The study aims to provide valuable information on the potential benefits of using Vepdegestrant and PF-07220060 together for treating this specific type of breast cancer. Participants will receive regular check-ups and assessments to track their progress and ensure their safety during the trial.

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 age, diagnosis of breast cancer, and previous treatments. Participants must be 18 years or older and have a diagnosis of advanced or metastatic breast cancer that cannot be surgically removed.

    Participants must have received at least one line of standard care for advanced or metastatic breast cancer and meet specific criteria regarding previous therapies.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to evaluate the participant's health status. This includes a review of medical history, physical examination, and laboratory tests.

    The assessment ensures that participants have the required measurable lesions and meet the performance status criteria.

  3. Step 3

    Treatment phase 1b

    Participants receive a combination of vepdegestrant and PF-07220060. The treatment is administered orally in the form of film-coated tablets.

    The primary goal is to assess the safety and tolerability of the combination to determine the recommended dosage.

  4. Step 4

    Treatment phase 2

    In this phase, the focus is on evaluating the antitumor activity of the treatment combination. Participants continue to receive the oral medication as determined in phase 1b.

    The effectiveness of the treatment is assessed through regular monitoring of tumor response and overall health.

  5. Step 5

    Monitoring and follow-up

    Throughout the trial, participants undergo regular monitoring, including blood tests, imaging studies, and assessments of side effects.

    The trial aims to track the duration of response, clinical benefit, and progression-free survival.

  6. Step 6

    Completion of the trial

    The trial is expected to conclude by March 2027. Participants will have a final assessment to evaluate the overall impact of the treatment.

    Data collected will contribute to understanding the safety and efficacy of the treatment combination for advanced or metastatic breast cancer.

Who can join the trial?

9 criteria

  • Participants must be **18 years or older** at the time of screening.
  • Must have a **diagnosis of breast cancer** that cannot be removed by surgery to cure it. The cancer must have **1% or more cells that are ER+** (estrogen receptor-positive) and **HER2-** (human epidermal growth factor receptor 2-negative) based on the most recent tumor biopsy.
  • Participants with **breast cancer in both breasts** that are ER+/HER2- are eligible.
  • A **tumor sample** collected at the time of diagnosis with local recurrent or metastatic disease or an **archival tumor tissue** is required for inclusion.
  • For Phase 1b: Participants should have received at least **one line of standard treatment** for advanced or metastatic breast cancer. Prior use of **fulvestrant** is allowed. No more than **one prior chemotherapy line** is allowed, and no antibody-drug conjugates are permitted.
  • For Phase 2: Participants must have had at least **one and a maximum of two lines of hormone therapy** for advanced or metastatic breast cancer, with the most recent hormone therapy lasting more than six months. They must have used **one CDK4/6 inhibitor** (a type of cancer treatment) in any setting. Up to **one prior chemotherapy regimen** is allowed, and no antibody-drug conjugates are permitted. Prior use of **fulvestrant** is allowed.
  • For Phase 1b: Participants with only **non-measurable lesions** (such as skin or bone lesions) are eligible.
  • For Phase 2: Participants must have at least **one measurable lesion** as defined by RECIST v1.1 (a standard way to measure cancer response to treatment). Participants with only bone lesions can be included if at least one bone lesion has a measurable component.
  • Participants must have an **ECOG performance status** of 0 or 1 for Phase 1b, and 0, 1, or 2 for Phase 2. This is a scale used to assess how a patient's disease is progressing, including their ability to perform daily activities.

Who cannot join the trial?

9 criteria

  • Patients with other types of cancer besides advanced or metastatic breast cancer cannot participate. This means the cancer has spread to other parts of the body.
  • Patients who are not able to safely take the study medications due to other health conditions or medications they are currently taking.
  • Patients who are pregnant or breastfeeding are not eligible to participate.
  • Patients who have participated in another clinical trial within a certain period before this study may be excluded.
  • Patients with certain heart conditions or other serious medical issues that could interfere with the study.
  • Patients who have had a recent surgery or are planning to have surgery during the study period.
  • Patients who have an active infection or other illness that could affect their ability to participate in the study.
  • Patients who have a history of allergic reactions to similar medications used in the study.
  • Patients who are unable to follow the study procedures or attend the required visits.
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Investigated drugs

  • Vepdegestrant (ARV-471/PF-07850327)

    is an oral medication being studied for its ability to target and degrade specific proteins involved in cancer growth. It is being tested for its safety and effectiveness in treating advanced or metastatic breast cancer that is positive for estrogen receptors (ER+) and negative for human epidermal growth factor receptor 2 (HER2-). This medication is part of a new class of treatments known as proteolysis targeting chimeras, which aim to break down proteins that contribute to cancer progression.

  • PF-07220060

    is another medication being tested in combination with vepdegestrant. It is being studied for its potential to enhance the antitumor effects when used alongside vepdegestrant in patients with ER+/HER2- advanced or metastatic breast cancer. The goal is to determine if this combination can improve treatment outcomes by effectively targeting cancer cells.

What is already known about the treatment

  • Vepdegestrant

    This medication is administered orally and is currently being studied in clinical trials for its safety and effectiveness. It is primarily being investigated for use in treating advanced or metastatic breast cancer, specifically in patients with ER+/HER2- subtypes. Vepdegestrant works by targeting and degrading specific proteins involved in cancer cell growth, using a mechanism known as proteolysis targeting chimera (PROTAC). It is classified as a targeted cancer therapy.

  • PF-07220060

    This medication is also administered orally and is under investigation in clinical trials for its potential benefits in treating advanced or metastatic breast cancer. It is being studied in combination with vepdegestrant to evaluate its safety and antitumor activity. The exact mechanism of action at the molecular level is not detailed, but it is part of a class of drugs aimed at inhibiting cancer cell proliferation.

Investigated diseases

Advanced or Metastatic Breast Cancer – This is a stage of breast cancer where the disease has spread beyond the breast and nearby lymph nodes to other parts of the body. It often affects organs such as the bones, liver, lungs, or brain. The progression of this cancer can vary, with some individuals experiencing rapid spread while others may have a slower progression. Symptoms can include pain, fatigue, and other signs depending on the organs affected. The disease is characterized by its ability to evade initial treatments and continue growing. Management focuses on controlling the spread and alleviating symptoms.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-508130-33-00Protocol codeC4891026Estimated enrolment65 patientsSponsorPfizer Inc.

sourced from the EU Clinical Trials Register and site verification

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