Study of elacestrant and exemestane treatment for patients with previously treated hormone receptor-positive, HER2-negative metastatic breast cancer with FES-avid lesions

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What is this study about?

This clinical study focuses on treating patients with metastatic breast cancer that is hormone receptor-positive and HER2-negative. The study will test a combination of two medications: elacestrant and exemestane. These medications are taken as tablets by mouth and work by targeting hormone receptors in cancer cells. Additionally, a special imaging substance called fluoroestradiol F-18 will be used to identify which tumors might respond to the treatment.

The purpose of this research is to evaluate how well the combination of elacestrant and exemestane works in treating this specific type of breast cancer. The study will include patients whose cancer has previously been treated with other therapies but has continued to grow or spread. During the study, patients will receive both medications and undergo various medical examinations to monitor their health and the effectiveness of the treatment.

This is a phase 2 clinical trial, which means it aims to gather more information about how well this combination treatment works. The treatment period may last up to 6 months, during which patients will take their medications daily. Throughout the study, doctors will closely monitor patients’ health and any side effects that may occur.

1 Initial screening and eligibility confirmation

Your medical history will be reviewed to confirm you are at least 18 years old and have hormone receptor-positive (HR+)/HER2-negative breast cancer that has spread.

A performance status check will be conducted to ensure you meet the ECOG score of 0 or 1 (able to carry out most daily activities).

Your organ function will be evaluated through medical tests.

2 Baseline imaging

You will receive an FES-PET/CT scan (a special type of imaging that shows how your tumor responds to hormones).

The scan will confirm that at least 50% of your visible tumor sites show sufficient uptake of the imaging agent.

3 Treatment initiation

You will begin taking two medications:

Elacestrant – taken by mouth daily

Exemestane – taken by mouth daily

4 Monitoring period

Regular assessments will track how your cancer responds to treatment using standard imaging.

Your overall health and any side effects will be monitored.

You will complete quality of life questionnaires at the start and after 8 weeks of treatment.

5 Ongoing evaluation

Treatment will continue as long as it is providing benefit and side effects are manageable.

Regular scans will be performed to check if the cancer is stable or responding to treatment.

The study will track how long the treatment keeps the cancer from growing.

Who Can Join the Study?

Must be at least 18 years old
Must have confirmed breast cancer that is:
- Hormone receptor-positive (showing at least 10% estrogen receptor presence)
- HER2-negative
- Either locally advanced (cannot be treated with surgery or radiation) or has spread to other parts of the body
Must be suitable for hormone therapy, which means:
- No critical organ involvement
- No severe symptoms
- Disease is not progressing rapidly
Must have either:
- Measurable tumors that can be evaluated using standard imaging
- Or bone-only disease with tumors that can be evaluated
At least half of measurable tumors must be visible on a special type of scan called FES-PET/CT
Must have previously received treatment with:
- A CDK4/6 inhibitor combined with either anastrozole or letrozole
- Treatment must have lasted at least 12 months
- Disease must have been stable during this treatment
Must have good physical ability status (ECOG score of 0 or 1, meaning able to perform daily activities)
Must have normal organ function

Who Cannot Join the Study?

Prior treatment with exemestane (a hormone therapy medication) in combination with any CDK4/6 inhibitor
Known brain metastases (cancer that has spread to the brain) that are untreated or unstable
Severe heart conditions including:
- Uncontrolled high blood pressure
- Unstable angina (chest pain)
- Heart attack within the past 6 months
Active or chronic liver disease (conditions affecting the liver)
Known severe allergic reactions to the study medications
Participation in another clinical trial within 30 days before starting this study
Current pregnancy or breastfeeding
Inability to swallow oral medications
Any serious medical condition that could interfere with study participation
History of other cancers within the past 3 years, except for successfully treated non-melanoma skin cancer or cervical cancer in situ

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

No sites found in this category

Other Sites

Site Name	City	Country	Status
Istituto Europeo Di Oncologia S.r.l.	Milan	Italy

Trial status

Country	Status	Recruitment Start
Italy	Recruiting	01.09.2025

Trial locations

Investigated drugs:

Elacestrant is a newer type of hormone therapy medication that works by blocking estrogen receptors in breast cancer cells. It is used to treat hormone receptor-positive breast cancer that has spread to other parts of the body. This medication helps prevent cancer growth by interfering with the hormone signaling that some breast cancers need to grow.

Exemestane is a hormone therapy medication known as an aromatase inhibitor. It works by reducing the amount of estrogen produced in the body of postmenopausal women. This medication is commonly used to treat hormone receptor-positive breast cancer by helping to stop or slow the growth of cancer cells that depend on estrogen to grow.

[18F]-FES is an imaging agent used in PET scans to help detect estrogen receptors in breast cancer. It is not a treatment but rather a diagnostic tool that helps doctors see where cancer cells that respond to estrogen are located in the body. This helps determine if hormone therapy treatments might be effective.

Investigated diseases:

Breast cancer metastatic

Hormone Receptor-Positive Breast Cancer – A type of breast cancer that grows in response to hormones estrogen and/or progesterone. Cancer cells in this type have receptors that allow them to use these hormones to grow. This form of breast cancer tends to develop more gradually than other types. When the cancer spreads beyond the breast to other parts of the body, it is called metastatic. The presence of hormone receptors on the cancer cells influences how the disease develops and progresses.

HER2-Negative Breast Cancer – A form of breast cancer where the cancer cells do not have high amounts of a protein called HER2 on their surface. These cancer cells do not respond to HER2-targeted treatments. This type of breast cancer makes up approximately 80% of all breast cancers. The cancer cells can still grow and spread, but they do so through different mechanisms than HER2-positive cancers.

Trial ID:

2024-519792-25-00

Protocol code:

UID 4270

Trial Phase:

Therapeutic exploratory (Phase II)

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Study of elacestrant and exemestane treatment for patients with previously treated hormone receptor-positive, HER2-negative metastatic breast cancer with FES-avid lesions

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?