The selective estrogen receptor degrader elacestrant appeared safe in the long term for patients with ER-positive, HER2-negative breast cancer, according to the 2025 ASCO Annual Meeting. The findings suggest that an all-oral therapy regimen may be a viable option for these patients.  

The analysis was an updated safety evaluation of the phase 1b/2 ELEVATE trial. The study tested elacestrant in combination with everolimus, alpelisib, capivasertib, ribociclib, palbociclib, or abemaciclib. The aim of the study was to evaluate progression-free survival (PFS) for patients taking each of these drug combinations, determine the safety of the combinations, and to find a recommended phase 2 dose of elacestrant. 

All patients had ER-positive, HER2-negative metastatic or advanced breast cancer, and received up to two lines of prior endocrine therapy, regardless of their tumors’ ESR1-mutational status. 

Previously, researchers reported that elacestrant significantly improved PFS in patients with this subtype of breast cancer. Elacestrant-based combinations also appeared to come with adverse event profiles similar to those of each drug with which elacestrant was paired. 

As of December 2024, the most common treatment-emergent adverse events for patients who received elacestrant with ribociclib, alpelisib, or capivasertib were nausea, diarrhea, stomatitis, and fatigue, the researchers reported. 

The researchers also identified the recommended phase 2 dose as 345 mg of elacestrant with 400 mg of ribociclib daily. 

“Elacestrant has the potential to become an endocrine therapy backbone for multiple targeted agents, providing an all-oral treatment option in pts with ER-positive, HER2-negative metastatic/advanced breast cancer, delaying chemo or ADC-based regimens.” 

- Nancy Chan, MD, director of breast cancer clinical research at NYU Langone’s Perlmutter Cancer Center, and colleagues 

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Reference: https://meetings.asco.org/abstracts-presentations/248697 

Disclosures: Authors declared financial ties to drugmakers. See full abstract for details.  

Photo Credit: Getty Images 

By Andrew Polhamus