Patients with a type of breast cancer that grows in response to estrogen (ER-positive) but does not have the HER2 protein (HER2-negative) often start treatment with hormone-blocking drugs.
Fulvestrant and aromatase inhibitors are common choices, often used alongside drugs called CDK4/6 inhibitors to help stop cancer cells from dividing. However, as the cancer progresses, it can become resistant to these treatments, partly due to mutations in certain genes, including one called ESR1.
When ESR1 mutates, aromatase inhibitors may no longer work, but other hormone therapies might still help. The problem is these options don’t keep cancer at bay for long once resistance develops, highlighting a need for new treatments.
Elacestrant is a new drug that has been approved for treating ER-positive, HER2-negative, ESR1-mutated metastatic breast cancer when the cancer has worsened after trying other hormone therapies. Unlike fulvestrant, which is injected, elacestrant is a pill.
This approval was based on a study showing that elacestrant could extend the time without cancer progression better than the standard treatments in patients with the ESR1 mutation.
Endocrine therapies, which block the effects of hormones on cancer cells, are often preferred because they have fewer side effects compared to chemotherapy, can be taken at home, and require less frequent visits to the hospital.
The approval of elacestrant offers a new, potentially more convenient option for patients, especially since it comes in pill form, avoiding the discomfort of injections required with fulvestrant.
In a significant trial, patients taking elacestrant saw an improvement in how long they lived without their cancer getting worse compared to those on standard hormone therapies. This benefit was particularly noticeable in patients with the ESR1 mutation, leading to its approval specifically for this group.
Elacestrant is taken daily as a pill, which might cause side effects like muscle pain, nausea, and changes in blood tests, but these are generally manageable. It’s important for healthcare providers to monitor patients’ blood lipid levels because the drug can affect cholesterol and triglyceride levels.
Since the ESR1 mutation makes some treatments ineffective, it’s crucial to test for this mutation when a patient’s cancer progresses despite treatment. This can help in deciding if elacestrant is the right option.
Elacestrant’s approval is a step towards more convenient and effective treatment options for breast cancer. With ongoing studies of elacestrant and other similar drugs in development, there’s hope for even more improvements in treating this disease, potentially changing the standard of care and improving patients’ quality of life.