Patrick Neven, MD, Universitair Ziekenhuis Leuven, Leuven, Belgium, presents data from the EMBER-2 window-of-opportunity study, in which imlunestrant was given for about 2 weeks before surgery in women with early, operable ER+, HER2– breast cancer. After treatment, tumor samples showed substantial reductions in estrogen receptor levels, progesterone receptor levels, and the proliferation marker Ki-67, indicating that imlunestrant effectively degraded ER and suppressed tumor cell proliferation.