In 83 adults in China with ER-positive, HER2-negative advanced breast cancer, imlunestrant ranges were wide and the sample was small

What the research found

Targeted Oncology published a Chinese subgroup of the phase III EMBER-3 trial on 9 November 2026. Xiaojia Wang, Jingwei Xu, and colleagues randomized 83 adults, ages 18 and older, with estrogen-receptor-positive, HER2-negative advanced breast cancer who had already had an aromatase inhibitor. From November 2022 to April 2025, 24 received imlunestrant, 29 received standard of care (fulvestrant or exemestane), and 30 received imlunestrant with abemaciclib. An ESR1 mutation was present in 6, 2, and 6 people. In that small mutation subset, median progression-free survival was 5.5 months on imlunestrant versus 2.7 on standard of care (hazard ratio 0.36; 95 percent CI 0.05 to 2.59). Imlunestrant with abemaciclib versus imlunestrant alone was 15.7 versus 5.5 months in the mutation subset (hazard ratio 0.43; 95 percent CI 0.11 to 1.75) and 7.4 versus 5.6 months in all 83 (hazard ratio 1.04; 95 percent CI 0.55 to 1.98). The authors say the ranges are too wide, and the counts too small, to prove a benefit. No new safety signal relative to the global trial was reported. 79 percent of people on fulvestrant reported injection-site pain or swelling at some point. NCT04975308. DOI 10.1007/s11523-026-01267-4. Not medical advice.

Evidence level: Clinical trial. This is among the stronger kinds of evidence, but one study rarely settles a question.

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