Selective Estrogen Receptor Degraders (SERDs) for Metastatic Breast Cancer

What are selective estrogen receptor degraders (SERDs)?

Selective estrogen receptor degraders (SERDs) are a type of hormone therapy. These anti-estrogen drugs bind to the estrogen receptor in a tumor cell. They cause the receptor to be broken down by the cell.

The SERDs that are FDA-approved for metastatic breast cancer treatment are:

Drug name

Brand name

Used in premenopausal or postmenopausal women?

How is it given?








Injection into the muscle

SERDs are hormone therapies used to treat some hormone receptor-positive metastatic breast cancers in postmenopausal women.

When a SERD is taken in pill form (orally), it may be called an oral SERD.

Learn more about fulvestrant and other hormone therapies for metastatic breast cancer.

Testing for ESRI tumor gene mutations

Some breast cancers have an ESR1 gene mutation. This mutation is in the genes of the breast cancer cells, not the genes of the person.

All hormone receptor-positive, HER2-negative metastatic breast cancers should be tested for ESR1 tumor gene mutations [6]. This can be done by testing tumor DNA in your blood or by testing tumor tissue.

Some metastatic breast cancers that have an ESR1 tumor gene mutation can be treated with the oral SERD elacestrant (Orserdu).

Elacestrant (Orserdu) and metastatic breast cancer treatment

Elacestrant may be used to treat hormone receptor-positive, HER2-negative metastatic breast cancers that have an ESR1 tumor gene mutation and have been treated with hormone therapy in the metastatic setting.

For postmenopausal women with these metastatic breast cancers, elacestrant may increase overall survival better than treatment with another hormone therapy drug [7].


For a summary of research studies on elacestrant and metastatic breast cancer treatment, visit the Breast Cancer Research Studies section.

Learn more about treatment for metastatic breast cancer.

Learn more about emerging areas in treatment for metastatic breast cancer.

How is elacestrant given?

Elacestrant is a pill.

Side effects of elacestrant

Before you begin taking elacestrant, talk with your health care provider about possible side effects and how to manage them.

Side Effects


Possible side effects include nausea, vomiting, fatigue, decreased appetite, muscle and joint pain, diarrhea, back pain, headache, constipation and hot flashes.

Elacestrant can increase cholesterol levels in your blood. Your cholesterol levels will be checked before you begin treatment and check regularly while you are taking this drug.

In some cases, elacestrant can cause liver problems.

Adapted from select sources [7-8].

Ashley Fernandez, living with metastatic breast cancer

“What keeps me going is my new normal. My life with cancer is completely different, I know I have it and I live with it every single day but it doesn’t take over every single day.”

Treatment guidelines for metastatic breast cancer

Although the exact treatment for metastatic breast cancer varies from person to person, guidelines help make sure high-quality care is given. These guidelines are based on the latest research and agreement among experts.

The National Comprehensive Cancer Network (NCCN) and the American Society of Clinical Oncology (ASCO) are respected organizations that regularly review and update their guidelines.

In addition, the National Cancer Institute (NCI) has treatment overviews.

Talk with your health care team about which treatment guidelines they follow.

Monitoring metastatic breast cancer

You’ll be monitored (checked) regularly with scans to see if the cancer is responding to treatment. If the treatment is no longer working, or you’re having a lot of side effects, your health care provider will change your treatment or discuss other options.

Learn more about how metastatic breast cancer is monitored.

When hormone therapy stops working

At some point, even though it may be years away, hormone therapy almost always stops working. At this point, chemotherapy or other therapies may be recommended.

Learn more about how metastatic breast cancer is monitored.

Clinical trials

Clinical trials offer the chance to try new treatments and possibly benefit from them.

Many clinical trials are available. Some are available as the first treatment for metastatic breast cancer. Others are for treatments later in the disease course. Consider joining a clinical trial when you’re newly diagnosed, when your oncologist is considering changing treatments or when there are limited treatment options.

Susan G. Komen® Patient Care Center

If you or a loved one needs information or resources about clinical trials, the Patient Care Center can help. Contact the Komen Breast Care Helpline at 1-877-465-6636 or email

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Metastatic Trial Search

The Metastatic Trial Search is a web-based clinical trial matching tool that can help you find clinical trials that fit your needs. You can also register to receive Trial Alerts.

Learn more about clinical trials for people with metastatic breast cancer.

Learn what Komen is doing to help people find and participate in breast cancer clinical trials, including trials supported by Komen.

Prescription drug assistance

The cost of drug therapies for metastatic breast cancer can quickly become a financial burden for you and your family.

Medicare and many insurance companies offer prescription drug plans. One may already be included in your policy, or you may be able to buy an extra plan for prescriptions.

You may also qualify for programs that help with drug costs or offer low-cost or free prescriptions.

Many cancer centers have financial counselors who can discuss insurance and cost coverage with you.

Learn more about insurance plans and prescription drug assistance programs.

Learn more about other financial assistance programs.

Komen Financial Assistance Program

Susan G. Komen® created the Komen Financial Assistance Program to help those struggling with the costs of breast cancer treatment by providing financial assistance to eligible individuals.

To learn more about this program and other helpful resources, call the Komen Breast Care Helpline at 1-877 GO KOMEN (1-877-465-6636) or email

Se habla español.

Susan G. Komen®‘s position on fairness in oral cancer drug coverage

Insurance coverage of oral cancer drugs

Cancer medications given through an IV into a vein or by an injection (under the skin or into a muscle) are usually covered under a health insurance plan’s medical benefit. However, cancer medications that are pills (oral cancer drugs) are usually covered under a health insurance plan’s prescription drug benefit.

As a result, people often find themselves facing high out-of-pocket costs when filling prescriptions for oral cancer drugs. Sometimes these costs can be thousands of dollars a month.

The impact of high cost-sharing

High prescription drug costs and the resulting out-of-pocket burden on patients are a barrier to care. They can prevent people from getting the medications prescribed by their health care providers.

No one should be forced to get less appropriate treatment because an insurer gives more coverage for IV and injectable drugs than for pills.

Efforts to increase fairness in drug coverage

Komen supports state and federal efforts to require insurers to provide the same or better coverage for oral cancer drugs as they do for IV and injectable cancer drugs. This would help make sure patients have access to affordable, appropriate treatment.

Become a Komen Advocacy Insider

Sign up to be a Komen Advocacy Insider and get informed when action is needed on drug coverage issues at the state or national level.


  • Do you need help with a metastatic breast cancer diagnosis? We’re here for you. The Komen Patient Care Center is your trusted, go-to source for timely, accurate breast health and breast cancer information, services and resources. Our navigators offer free, personalized support to patients, caregivers and family members, including education, emotional support, financial assistance, help accessing care and more. Get connected to a Komen navigator by contacting the Breast Care Helpline at 1-877-465-6636 or email to get started. All calls are answered Monday through Thursday, 9 a.m to 7 p.m. ET and Friday, 9 a.m. to 6 p.m. ET. Se habla español.
  • We offer an online support community through our closed Komen Metastatic Breast Cancer (Stage IV) Group. The Facebook group provides a place where those living with metastatic breast cancer, and those who love them, can find support, friendship and information. Click the link above or visit Facebook and search for Komen Metastatic Breast Cancer (Stage IV) Group and request to join.
  • Our free MBC Impact Series provides people living with metastatic breast cancer and their loved ones a safe, collaborative space to gather information related to metastatic breast cancer and discover practical resources to help make decisions for improved physical and emotional health. To learn more and register visit
  • Our Real Pink podcast series covers many relevant topics for people living with metastatic breast cancer and caregivers.
  • Our fact sheets, booklets and other education materials offer additional information.

Updated 03/27/24