Orserdu (elacestrant)

Treatment paradigms have advanced from non-targeted options, such as fulvestrant monotherapy or everolimus-based combinations, to precision medicine strategies, including inhibitors of the PI3K/AKT pathway, oral selective estrogen receptor degraders (SERDs), and novel ER-modulating agents, often guided by biomarkers and molecular surveillance... Early second-line standards, including fulvestrant and alpelisib for PIK3CA-mutated tumors, established the basis for biomarker-guided treatment in hormone receptor-positive, HER2-negative metastatic breast cancer...Elacestrant improved progression-free survival in ESR1-mutated disease in the EMERALD trial, capivasertib plus fulvestrant demonstrated significant benefit in tumors harboring AKT/PIK3CA/PTEN pathway alterations in CAPItello-291, and inavolisib plus palbociclib and fulvestrant achieved both progression-free and overall survival improvement in PIK3CA-mutated patients with early relapse in INAVO120... Post-CDK4/6i management increasingly relies on NGS-guided precision approaches, integrating pathway-specific therapies and ctDNA surveillance to tailor sequencing based on resistance profiles, prior ET response, and tumor heterogeneity. Future investigations into novel ER degraders and multi-targeted combinations hold potential to further optimize algorithms, extend non-chemotherapy options, and enhance survival in HR+/HER2- mBC.

P=N/A, N=500, Recruiting, iOMEDICO AG | Not yet recruiting --> Recruiting | Trial completion date: Jul 2029 --> Jun 2028

These results demonstrate that both dPCR and NGS-based liquid biopsy workflows can be successfully implemented for ESR1 mutation testing in routine clinical practice using locally validated assays. This multicentre verification study provides practical guidance on assay verification, DNA input requirements, and key analytical parameters required to ensure reliable ESR1 mutation detection across different European laboratories. Robust analytical verification of ESR1 testing may improve diagnostic reliability and support personalized treatment strategies for patients with hormone receptor-positive, HER2-negative metastatic breast cancer.

P1/2, N=435, Active, not recruiting, Stemline Therapeutics, Inc. | Recruiting --> Active, not recruiting

P2, N=50, Not yet recruiting, Jonsson Comprehensive Cancer Center

The regulatory approval of elacestrant for ESR1-mutant disease and randomized trial data showing progression-free survival (PFS) benefit from ctDNA-guided endocrine switching (PADA-1, SERENA-6) position ESR1 genotyping as a dynamic biomarker with direct therapeutic implications...The convergence of structural mechanisms, liquid biopsy technology, and biomarker-driven drug development provides a framework for precision oncology in endocrine-resistant breast cancer. While these advances are substantial, important challenges remain, including the lack of mature overall survival (OS) data from interception trials, cost and accessibility barriers to serial ctDNA monitoring in diverse global healthcare settings, the unresolved question of optimal therapeutic sequencing in patients with concurrent ESR1 and PI3K pathway alterations, and the need to distinguish clinically actionable low-variant allele frequency (VAF) ESR1 calls from background noise in liquid biopsies.

P1/2, N=50, Recruiting, NYU Langone Health

Oral SERDs are reshaping the management of ESR1-mutant disease, with agents such as elacestrant and imlunestrant emerging as standard second-line options. However, primary resistance to SERD monotherapy remains substantial, highlighting the need for combination strategies. Future directions include ctDNA-guided approaches and expansion into earlier treatment settings.

P2, N=26, Recruiting, European Institute of Oncology | Not yet recruiting --> Recruiting

P1/2, N=26, Recruiting, Istituto Europeo Di Oncologia S.r.l. | Not yet recruiting --> Recruiting

P3, N=1520, Recruiting, West German Study Group | Not yet recruiting --> Recruiting

P=N/A, N=500, Not yet recruiting, iOMEDICO AG