Eli Lilly has reported fresh Phase 3 data showing its oral breast cancer drug significantly reduced disease progression and extended survival in patients with advanced breast cancer.

 

This bolsters the case for its use both alone and in combination therapy, as per the global pharma company.

 

Updated results from the EMBER-3 study showed that the drug -- Inluriyo (imlunestrant) -- as a standalone treatment cut the risk of progression or death by 38% compared with standard endocrine therapy in patients whose tumors carried ESR1 mutations. 

 

Median progression-free survival improved to 5.5 months from 3.8 months, while overall survival increased by more than 11 months, reaching 34.5 months versus 23.1 months, although the predefined boundary for statistical significance was not met.

 

In a separate analysis of all enrolled patients, combining imlunestrant with the CDK4/6 inhibitor abemaciclib reduced the risk of progression or death by 41% compared with imlunestrant alone, nearly doubling progression-free survival and delaying the need for chemotherapy by more than a year.

 

The findings were published in Annals of Oncology.

 

"Following the recent FDA approval of Inluriyo as monotherapy, these updated data demonstrate continued clinically meaningful benefit—both for patients receiving monotherapy and those receiving the combination with abemaciclib—and further reinforce its role in this treatment setting," said Jacob Van Naarden, executive vice president and president, Lilly Oncology. 

 

"Given the important role of CDK4/6 inhibitors in treating ER+, HER2– metastatic breast cancer, we're encouraged by the potential of an all-oral combination with imlunestrant and abemaciclib and have submitted these combination data for U.S. regulatory review in ESR1-mutated MBC."

 

Across the full study population, patients receiving the combination therapy achieved a median progression-free survival of 10.9 months, compared with 5.5 months for those on imlunestrant alone. A favorable overall survival trend was observed, with survival curves continuing to separate over time. Time to chemotherapy was extended to nearly 28 months, versus 15.5 months with monotherapy.

 

Among patients with ESR1-mutated disease, progression-free survival reached 11.0 months with the combination, compared with 5.6 months on imlunestrant alone. Notably, nearly two-thirds of patients in the combination arm had already been treated with a CDK4/6 inhibitor.

 

"With an additional year of follow-up, these results strengthen the case for imlunestrant-based regimens in ER+, HER2– metastatic breast cancer," said Komal Jhaveri, Associate Attending Breast Medicine and Early Drug Development Services, section head of Endocrine Therapy Research Program at Memorial Sloan Kettering Cancer Center, and one of the study's principal investigators. 

 

"The median progression-free survival of 11 months is among the longest we've seen in this population, and just as importantly, patients are living longer without needing chemotherapy."

 

Lilly reported that the safety profile of imlunestrant, both alone and in combination, remained consistent with earlier findings, with no new safety signals observed. Overall survival follow-up is ongoing, with further analyses planned as the data mature.

 

Beyond metastatic disease, Lilly is also testing imlunestrant in early-stage breast cancer. The Phase 3 EMBER-4 trial has completed enrollment of roughly 8,000 patients in the adjuvant setting, targeting those at increased risk of recurrence following standard endocrine therapy.