FDA Approves Orserdu for Metastatic, Estrogen Receptor-Positive Breast Cancer


Written by Jamie DePolo Jan 27, 2023.

The FDA has approved Orserdu, a new oral medicine to treat metastatic, estrogen receptor-positive, HER2-negative breast cancer with an ESR1 mutation.

On Jan. 27, 2023, the U.S. Food and Drug Administration (FDA) approved Orserdu (chemical name: elacestrant) to treat advanced-stage or metastatic, estrogen receptor-positive, HER2-negative breast cancer with an ESR1 mutation that has grown after being treated with at least one hormonal therapy medicine in men or post-menopausal women.

Read the FDA announcement

Advanced-stage breast cancer is either locally advanced or metastatic. Locally advanced breast cancer means the cancer has spread to tissue near the breast, but not to parts of the body away from the breast. Metastatic breast cancer means the cancer has spread to parts of the body away from the breast, such as the bones or liver. 

About Orserdu

Orserdu is a type of hormonal therapy called a selective estrogen receptor downregulator or degrader (SERD). SERDs work by blocking the effects of estrogen on hormone receptor-positive breast cancer cells by sitting in the estrogen receptors on the cells. If a SERD is in the receptor, there is no room for estrogen to attach itself to the cell. If estrogen isn’t attached to the cancer cell, the cell doesn’t receive estrogen’s signals to grow and multiply.

SERDs also:

  • reduce the number of estrogen receptors
  • change the shape of estrogen receptors so they don’t work as well

Orserdu is a pill taken by mouth. You take one Orserdu pill a day, with food.

Faslodex (chemical name: fulvestrant) is another SERD approved to treat breast cancer. Faslodex is a liquid that is injected into a muscle once a month, usually at a doctor’s office. Many people would rather take a pill at home than go to a doctor’s office to get an injection. So researchers have been working to create an oral SERD.

About ESR1 mutations

The ESR1 gene makes proteins that are estrogen receptors. The receptors receive signals from estrogen that tell the cancer to grow.

Most metastatic, estrogen receptor-positive breast cancers initially respond to hormonal therapy medicines, but become resistant after a while.

Research has shown that when the ESR1 gene develops a change or mutation, it can cause the breast cancer to become resistant to hormonal therapy.

Orserdu research: The EMERALD study

FDA approval of Orserdu was based on results from the EMERALD study. The study included 477 post-menopausal women and men diagnosed with metastatic, estrogen receptor-positive, HER2-negative breast cancer that had grown while being treated with hormonal therapy and a CDK4/6 inhibitor.

CDK4/6 inhibitors are a class of medicines used to treat certain types of hormone receptor-positive, HER2-negative breast cancers. These medicines target specific proteins known as cyclin-dependent kinases 4 and 6, abbreviated as CDK4/6. These kinases help control cell division. CDK4/6 inhibitors work by interfering with the kinases and stopping cancer cells from dividing and growing.

Everyone in the study had received one or two previous hormonal therapy regimens, and no one had received chemotherapy for metastatic breast cancer.

About half the people in the study were diagnosed with breast cancer that had an ESR1 mutation.

The researchers randomly assigned the people to one of two treatments:

  • 239 people received Orserdu
  • 238 people received the standard of care, which was the researchers’ choice of either Faslodex or an aromatase inhibitor

The results showed that people who took Orserdu had a 45% lower risk of the cancer growing or of dying from the cancer than people who received Faslodex or took an aromatase inhibitor. The results also showed that Orserdu was effective in treating breast cancer with an ESR1 mutation.

Orserdu side effects

Like almost all cancer medicines, Orserdu can cause side effects, some of them severe.

In the EMERALD study, nausea was the most common side effect of Orserdu.

Other possible Orserdu side effects are:

  • fatigue
  • vomiting
  • joint pain
  • loss of appetite
  • diarrhea
  • back pain

What this means for you

If you’ve been diagnosed with metastatic, hormone receptor-positive, HER2-negative breast cancer with an ESR1 mutation that has grown during treatment with hormonal therapy, you may want to ask your doctor about Orserdu and whether it’s right for your unique situation.

Last updated on February 13, 2023 at 2:17 PM

This information is provided by Breastcancer.org.

Posted in: Medical/Science