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Study on PF-07220060, Letrozole, and Fulvestrant for Patients with Advanced Breast Cancer, Prostate Cancer, and Other Solid Tumors

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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 advanced solid tumors, which are types of cancer that have spread beyond their original location. The study involves several types of cancer, including breast cancer, non-small cell lung cancer (NSCLC), prostate cancer, colorectal cancer (CRC), and liposarcoma. It also includes tumors with specific genetic changes known as CDK4 or CCND1 amplification. The main treatment being tested is a new medication called PF-07220060, which is being evaluated both on its own and in combination with other treatments. These other treatments include letrozole, fulvestrant, and enzalutamide, which are medications commonly used in treating certain types of cancer.

The purpose of the study is to assess the safety and effectiveness of PF-07220060 in treating these advanced cancers. Participants will receive the medication in tablet form, taken by mouth, and in some cases, it will be combined with other cancer treatments. The study will also explore how the body processes the medication and how it affects the tumors. Some participants will receive a placebo, which is a substance with no active medication, to help compare the effects of the treatment.

The study will be conducted in different parts, each focusing on specific types of cancer and treatment combinations. Participants will be monitored for safety and any side effects, and the study will help determine the best dose of PF-07220060 to use in future research. The trial is expected to continue until 2026, with the goal of finding new and effective ways to treat advanced solid tumors.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes reviewing medical history and current health status.

    Participants must have specific types of cancer, such as breast cancer, prostate cancer, or other tumors with certain genetic markers.

  2. Step 2

    Treatment phase 1

    Participants receive the medication PF-07220060 orally. The dosage is adjusted in successive groups to determine the safest and most effective dose.

    The goal is to assess the safety and how well the body tolerates the medication.

  3. Step 3

    Combination therapy

    In some cases, PF-07220060 is combined with other medications like letrozole or fulvestrant for breast cancer, or enzalutamide for prostate cancer.

    The combination aims to enhance treatment effectiveness while monitoring safety and side effects.

  4. Step 4

    Food effect evaluation

    Participants may be asked to take PF-07220060 with and without food to study how food affects the medication's absorption and effectiveness.

  5. Step 5

    Repeated administration

    The effect of taking PF-07220060 repeatedly is evaluated to understand its impact over time and to ensure consistent results.

  6. Step 6

    Monitoring and follow-up

    Throughout the trial, regular monitoring of health status, side effects, and treatment response is conducted.

    Participants undergo various tests and assessments to track progress and adjust treatment as necessary.

  7. Step 7

    Trial completion

    The trial is expected to conclude by July 2026. Participants will have a final assessment to evaluate the overall impact of the treatment.

Who can join the trial?

12 criteria

  • Participants must be at least 18 years old.
  • Participants must have a type of cancer that fits the study requirements, such as breast cancer, prostate cancer, or other specific tumors.
  • Participants must have tried existing treatments that are known to help their condition but are no longer effective or cannot be tolerated.
  • Participants must have adequate liver function, which means their liver is working well enough based on specific blood test results.
  • Participants must have adequate bone marrow function, which means their blood cell levels are within a certain range.
  • Participants must have adequate kidney function, which means their kidneys are working well enough based on a specific test.
  • Participants must be able to understand and sign a consent form, agreeing to follow the study's rules and procedures.
  • Participants must be willing and able to attend scheduled visits, follow the treatment plan, and undergo necessary tests and procedures.
  • Women of any menopausal status can participate, but those who are not post-menopausal must be willing to receive a specific hormone treatment.
  • Participants must have a specific type of cancer lesion that can be evaluated or measured according to the study's requirements.
  • Participants must have received certain prior treatments for their cancer, depending on the part of the study they are joining.
  • Participants must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, which means they are fully active or have some restrictions but can still do light work.

Who cannot join the trial?

7 criteria

  • Patients with other types of cancer not specified in the study.
  • Patients who have not been diagnosed with tumors that have a specific genetic change called **CDK4** or **CCND1 amplification**.
  • Patients who are not diagnosed with **HR-positive**/**HER2-negative** breast cancer. **HR-positive** means the cancer grows in response to hormones, and **HER2-negative** means the cancer does not have a protein called HER2 on its surface.
  • Patients who do not have **mCRPC**, which stands for metastatic castration-resistant prostate cancer. This is a type of prostate cancer that has spread to other parts of the body and does not respond to treatments that lower testosterone.
  • Patients who are not within the specified age range for the study.
  • Patients who are not part of the specified clinical trial groups.
  • Patients who are not considered part of the vulnerable population selected for the study.
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Investigated drugs

  • PF-07220060

    is an experimental medication being studied for its potential to treat various advanced solid tumors. It is being tested both as a single treatment and in combination with other medications. The study aims to understand how safe and tolerable PF-07220060 is for patients, as well as how it behaves in the body and its potential effectiveness against tumors.

  • Letrozole

    is a medication used in combination with PF-07220060 in this study. It is commonly used to treat certain types of breast cancer by lowering estrogen levels in the body, which can help slow or stop the growth of some breast cancer cells.

  • Fulvestrant

    is another medication used in combination with PF-07220060. It is used to treat hormone receptor-positive breast cancer by blocking the effects of estrogen in the body, which can help slow the growth of cancer cells.

  • Enzalutamide

    is a medication used in combination with PF-07220060 for patients with metastatic castration-resistant prostate cancer (mCRPC). It works by blocking the effects of male hormones that can promote the growth of prostate cancer cells.

What is already known about the treatment

PF-07220060 – This medication is administered orally and is currently being studied in clinical trials for its safety and effectiveness in treating various advanced solid tumors, including breast cancer, prostate cancer, and other tumors with specific genetic markers. It is in the investigational stage, meaning it is not yet approved for general medical use. The main therapeutic indications include HR-positive/HER2-negative breast cancer and prostate cancer. PF-07220060 works by targeting specific proteins involved in cell cycle regulation, potentially inhibiting tumor growth. It is classified pharmacologically as a targeted cancer therapy.

Investigated diseases

  • Breast Cancer

    A disease where cells in the breast grow uncontrollably, forming a tumor. It can be hormone receptor-positive (HR-positive) or HER2-negative, affecting how the cancer grows and spreads. Over time, it may invade nearby tissues or spread to other parts of the body.

  • Non-Small Cell Lung Cancer (NSCLC)

    A type of lung cancer that includes several subtypes, such as adenocarcinoma and squamous cell carcinoma. It generally grows and spreads more slowly than small cell lung cancer. As it progresses, it can invade nearby tissues and spread to other parts of the body.

  • Prostate Cancer

    A cancer that occurs in the prostate gland, which is part of the male reproductive system. It often grows slowly and may initially cause few symptoms. Over time, it can spread to nearby tissues and other parts of the body.

  • Colorectal Cancer (CRC)

    A cancer that starts in the colon or rectum, part of the digestive tract. It often begins as a growth called a polyp, which can become cancerous over time. As it progresses, it can invade nearby tissues and spread to other areas of the body.

  • Liposarcoma

    A rare type of cancer that develops in fat cells, often in the limbs or abdomen. It can vary in aggressiveness, with some forms growing slowly and others spreading quickly. As it progresses, it can invade nearby tissues and spread to other parts of the body.

  • Metastatic Castration-Resistant Prostate Cancer (mCRPC)

    An advanced form of prostate cancer that continues to grow despite low levels of testosterone. It can spread to bones, lymph nodes, and other organs. Over time, it may cause symptoms such as pain and difficulty urinating.

Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase I/IITrial ID2024-512120-11-00Protocol codeC4391001Estimated enrolment400 patientsSponsorPfizer Inc.

sourced from the EU Clinical Trials Register and site verification

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).