Fulvestrant + abemaciclib enables cytoreduction in unresectable LGSOC

Fulvestrant is an intramuscular selective estrogen receptor degrader, and abemaciclib is an oral CDK4/6 inhibitor targeting ER-driven cell-cycle signaling. In a pilot Phase 2 neoadjuvant study in advanced, initially unresectable low-grade serous ovarian carcinoma (LGSOC; NCT03531645), 15 evaluable patients achieved a 100% clinical benefit rate, including 7% CR, 53% PR, and 40% SD; 60% proceeded to interval cytoreductive surgery, and 78% of those achieved complete/optimal resection. That compares favorably with the historically low activity of neoadjuvant platinum chemotherapy in LGSOC, where reported response rates are often ~4%–11%, and it fits the broader shift toward endocrine/MAPK/cell-cycle approaches in this relatively chemoresistant disease.