Elacestrant, the New Breast Cancer Drug, is Here! Which Patients Can Benefit? How Effective is It? All Answered in This Article

"World’s first new breast cancer drug debuts in China – doubling patients’ survival time!"

Recently, this post has attracted considerable attention on Rednote. The drug mentioned is elacestrant tablets, a clinically urgently needed imported medicine from Hong Kong and Macao introduced under the new policy of the Guangdong-Hong Kong-Macao Greater Bay Area.

Words like "doubled survival time", "first-in-class" and "new hope" together inevitably arouse great expectations. But is this the whole truth? Which patients can actually benefit from this drug? How effective is it exactly?

Let’s break it down in detail today.

1. It’s Not a "Miracle Drug", but Precisely Targets a Type of Refractory Breast Cancer

Elacestrant is an oral selective estrogen receptor degrader (SERD), and it is the world’s first and currently the only approved oral SERD for the treatment of advanced breast cancer. Its targeted population is very specific: patients with estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer who have ESR1 gene mutations.

Why is the ESR1 mutation particularly emphasized?

Endocrine therapy has long been an important treatment for ER+/HER2- breast cancer, but drug resistance has become an increasingly prominent issue with the progression of treatment, among which ESR1 mutation is one of the major causes of endocrine resistance.

Data shows that the incidence of ESR1 mutations is relatively low in treatment-naive HR+ breast cancer patients. However, the incidence rises significantly in advanced patients who have received aromatase inhibitor (AI) therapy, reaching 20%-40% in some studies. Especially after treatment with CDK4/6 inhibitor combined with AI, the ESR1 mutation rate can reach 40%.

Elacestrant’s mechanism of action is precisely targeted at this drug resistance mechanism through a dual approach: on the one hand, it binds to the estrogen receptor (ER) to prevent carcinogenic estrogen from binding to the receptor (antagonistic effect); on the other hand, it induces the ER to be recognized and degraded by the cell’s "waste disposal system", reducing the number of ERs at the source (degradative effect), thus overcoming the drug resistance caused by traditional endocrine therapy.

2. What Do the Clinical Data Show? Does It Really "Double Survival Time"?

The approval of elacestrant is mainly based on the phase III EMERALD clinical study, whose results were published in the Journal of Clinical Oncology in 2022.

The study enrolled ER+/HER2- advanced breast cancer patients whose disease progressed after previous treatment with a CDK4/6 inhibitor combined with endocrine therapy. The results showed:

· In all patients, elacestrant reduced the risk of disease progression or death by 30% compared with standard endocrine therapy (fulvestrant or aromatase inhibitor).

· For patients with ESR1 mutations, the advantages of elacestrant were more significant: it reduced the risk of disease progression or death by 45%, and extended the median progression-free survival (PFS) from 1.9 months with standard treatment to 3.8 months, achieving a doubling of PFS.

The most prominent efficacy was observed in the subgroup of patients with ESR1 mutations who had received CDK4/6 inhibitor treatment for ≥12 months:

· Median PFS in the elacestrant group: 8.6 months

· Median PFS in the standard treatment group: 1.9 months

· Hazard ratio (HR) was 0.41, meaning a 59% reduction in the risk of progression or death.

8.6 months vs 1.9 months – literally, this difference can be interpreted as a several-fold increase in "survival time". However, it is crucial to clarify that the "survival time" here refers to progression-free survival (the time during which the disease is controlled), not overall survival (OS), whose data is still maturing.

In other words, for this specific subgroup of patients, elacestrant has indeed extended the disease control time from less than 2 months to nearly 9 months, which is a clinically meaningful progress. But it is not suitable for all breast cancer patients, let alone a "cure".

Elacestrant consistently demonstrated superior efficacy in patients with bone metastases, liver/lung metastases, different numbers of metastatic lesions, and even different types of ESR1 mutations.

Based on these data, the US FDA granted accelerated approval to elacestrant on January 27, 2023, for the treatment of ER+/HER2-, ESR1 mutation-positive advanced metastatic breast cancer, under the brand name Orserdu.

Notably, elacestrant has quickly gained recognition from authoritative international and domestic guidelines:

· The 2024 National Comprehensive Cancer Network (NCCN) Guidelines updated elacestrant independently, listing it as an important recommendation for the second-line and subsequent treatment of advanced HR+/HER2- breast cancer.

· Even before its official approval in China, the Chinese Anti-Cancer Association (CACA) Guidelines have included elacestrant as an optional treatment option.

3. Advantages of the Oral Formulation: More Convenient and Patient-Friendly

Unlike fulvestrant, a traditional SERD that requires intramuscular injection, elacestrant is an oral preparation taken once a day. It spares patients from frequent hospital visits for injections or infusions, greatly improving the convenience of treatment and quality of life, and making "home-based treatment" a reality.

In terms of safety, elacestrant is generally well-tolerated, with most common adverse events being grade 1-2 and clinically manageable.

· Nausea and vomiting: mostly grade 1-2, effectively managed by taking the drug with meals or using prophylactic antiemetics.

· Dyslipidemia: some patients may experience elevated cholesterol or triglycerides, controllable through regular monitoring and dietary/drug interventions.

· Fatigue, arthralgia, etc.

In an early preoperative exploratory study (the ELIPSE trial), elacestrant also showed a manageable safety profile, with common adverse events including grade 1 anemia (21.7%), hot flashes (8.7%), and constipation (8.7%).

4. How Can Patients Access Elacestrant in China?

At present, elacestrant has not yet obtained official approval from the National Medical Products Administration (NMPA) of China, but it is available for use in designated medical institutions in the Guangdong-Hong Kong-Macao Greater Bay Area through the "Hong Kong-Macao Medicine and Medical Devices Connect" policy.

Officially launched in 2021, the "Hong Kong-Macao Medicine and Medical Devices Connect" policy allows clinically urgently needed drugs already marketed in Hong Kong and Macao to be used in designated medical institutions in the mainland of the Greater Bay Area through special permission for import.

On December 8, 2025, the Guangdong Provincial Health Commission and the Guangdong Provincial Medical Products Administration jointly issued a notice announcing the fourth batch of designated medical institutions under the "Hong Kong-Macao Medicine and Medical Devices Connect" policy, with Guangzhou Taihe Cancer Hospital being approved for inclusion. The hospital has officially become one of the designated medical institutions authorized to use clinically urgently needed drugs and medical devices marketed in Hong Kong and Macao but not yet registered in the mainland under this policy.

As of February 28, 2026, a total of 66 drugs and 87 types of medical devices have been approved for use in designated medical institutions under the "Hong Kong-Macao Medicine and Medical Devices Connect" policy.

In the field of breast cancer treatment, Guangzhou Taihe Cancer Hospital is currently one of the designated medical institutions explicitly authorized to use elacestrant.

Final Thoughts

Returning to the question at the beginning: is elacestrant really that "miraculous"?

The answer is: for eligible specific patients, it is indeed an important treatment breakthrough.

Its applicable population is highly specific: advanced breast cancer patients with ER+/HER2-, ESR1 mutations, and drug resistance to CDK4/6 inhibitor combined with endocrine therapy. For this group of patients, it can extend the disease control time from less than 2 months to nearly 9 months.

If you or your relatives are considering this drug, it is recommended to first consult the opinion of a breast cancer specialist/attending physician, and confirm the following two points:

· Whether the breast cancer is of ER+/HER2- subtype.

· Whether there is an ESR1 gene mutation (to be determined through genetic testing of blood or tumor tissue).

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