Inluriyo (imlunestrant)

In this ITC analysis of patient-level data from three phase III trials, although not powered for formal hypothesis testing, the all-oral targeted combination therapy imlunestrant + abemaciclib showed a consistent numerical reduction in the risk of disease progression or death compared with fulvestrant + abemaciclib in patients with ER-positive/HER2-negative ABC previously treated with endocrine therapy ± CDK4/6i.

Key 2025 findings (50 clinical trials) include: (1) confirmation of overall survival benefit with adjuvant CDK4/6 inhibitors in HR+/HER2- early breast cancer (monarchE: HR = 0.842, p = 0.0273); (2) establishment of trastuzumab deruxtecan (T-DXd) as a new standard in high-risk HER2+ early disease (DESTINY-Breast05: IDFS HR = 0.47) and first-line metastatic settings (DESTINY-Breast09: PFS HR = 0.58); (3) validation of TROP2-directed ADCs as first-line therapy for metastatic triple-negative breast cancer (ASCENT-03: PFS HR = 0.62; BEGONIA: ORR 79%); (4) paradigm shift to proactive, liquid biopsy-guided therapy switching (SERENA-6: PFS HR = 0.44); (5) updated efficacy and safety of the oral SERD imlunestrant from the EMBER-3 trial, supporting its role in ESR1-mutated advanced breast cancer and in combination with abemaciclib; (6) confirmation of long-term survival benefit for neoadjuvant carboplatin in early TNBC and new positive adjuvant data; (7) pivotal advances in HER2+ metastatic disease sequencing with tucatinib and T-DXd; (8) evidence supporting optimized adjuvant endocrine therapy in HER2+/HR+ early disease; and (9) emergence of novel agents with improved therapeutic indices, including PROTAC degraders, oral SERDs, and mutant-selective PI3K inhibitors. Unifying themes include biomarker-driven personalization, strategic treatment sequencing, management of unique toxicities, and emphasis on patient-reported outcomes. Future challenges include optimizing treatment integration, managing financial toxicity, and ensuring equitable global access.

P2, N=189, Not yet recruiting, Fudan University

P3, N=8000, Active, not recruiting, Eli Lilly and Company | Recruiting --> Active, not recruiting

P1, N=193, Active, not recruiting, Eli Lilly and Company | Trial completion date: Dec 2025 --> Dec 2026 | Trial primary completion date: Dec 2025 --> Dec 2026

P2, N=600, Not yet recruiting, Eli Lilly and Company | Trial completion date: Jan 2029 --> Dec 2029

P2, N=600, Not yet recruiting, Eli Lilly and Company

These findings reinforce the clinical benefit of imlunestrant-based regimens as a potential all-oral, chemotherapy-free treatment option for endocrine-pretreated patients with ER+, HER2-ABC.

In September 2025, imlunestrant was approved for the treatment of adults with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy in the USA. This article summarizes the milestones in the development of imlunestrant leading to this first approval for use in patients with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer.

P2, N=42, Not yet recruiting, Jonsson Comprehensive Cancer Center | Trial completion date: Sep 2031 --> Apr 2031 | Initiation date: Sep 2025 --> Apr 2026 | Trial primary completion date: Sep 2030 --> Apr 2030