A new drug improves clinical outcomes for patients with advanced breast cancer

A phase 3 clinical trial demonstrates that the combination of imlunestrant and abemaciclib improves progression-free survival in advanced ER+ HER2- breast cancer, regardless of the genomic profile. The compound as monotherapy only shows benefits in patients with mutations in the ESR1 gene

The results of the EMBER-3 clinical trial were presented at the San Antonio Breast Cancer Symposium (SABCS), being held in San Antonio, Texas, from December 10-13. 

In the study, published in parallel in the journal The New England Journal of Medicine. participated 874 women with breast cancer advanced estrogen receptor-positive (ER+) and HER2-negative (HER2-) cancer who had progressed following endocrine therapy. Participants were randomly assigned to receive imlunestrant monotherapy, the imlunestrant-abemaciclib combination, or standard endocrine therapy.

«Combination of imlunestrant and abemaciclib improves progression-free survival in patients with ER+ HER2 advanced breast cancer»

The combination of imlunestrant and abemaciclib increased the median progression-free survival to 9,4 months compared with 3,8 months for standard therapy. However, imlunestrant alone only demonstrated benefits in people with mutations in the ESR1 gene, reaching a median of 5,5 months compared with 3,8 months for conventional treatment.

Breast cancer is the most common type of cancer in women and the second most common overall in the world, with approximately 2,3 million diagnoses in 2022. Although current treatments such as selective estrogen receptor modulators (SERMs), aromatase inhibitors, and SERDs have improved outcomes, many tumors develop resistance, especially in the presence of mutations in the ESR1 gene, which encodes the estrogen receptor.

"The new drug is not yet approved by regulatory agencies for clinical use."

low toxicity

Imlunestrant is a next-generation oral SERD drug that acts as a pure estrogen receptor antagonist, providing sustained inhibition even in tumors with ESR1 mutation. In preliminary studies such as EMBER-1, it demonstrated low-grade toxicity, favorable pharmacokinetics and encouraging antitumor activity.

“Tumors with mutations in ESR1 have a worse prognosis, so new therapeutic options are needed,” said Cristina Saura, head of the Breast Cancer Unit at Vall d'Hebron University Hospital and co-author of the study. She stressed that new SERD drugs, such as imlunestrant, could optimize treatments based on the genomic characteristics of the tumor.

Saura also warned that "this new drug is not yet approved by regulatory agencies for clinical use," but considered that the results open "a window of opportunity" for the development of new personalized therapies.

Source: VHIO

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