Type of publication:
Conference abstract
Author(s):
Koliou P.; O'Brien C.S.; Levitt N.; Twelves C.J.; *Pettit L.; Nathan M.; Khan S.; Luttropp K.A.; Pastrello D.; Jarvis R.S.; Oikonomidou O.
Citation:
ESMO Open. Conference: ESMO Open Science for Optimal Cancer Care. Berlin Germany. 11(Supplement 4) (no pagination), 2026. Article Number: 107596. Date of Publication: 01 May 2026.
Abstract:
Background: This subgroup analysis of UK patients from a prior multi-national chart review described characteristics and outcomes of those with HR+/HER2- advanced/metastatic breast cancer (ABC) receiving the cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) abemaciclib with an aromatase inhibitor (AI) or fulvestrant as initial endocrine-based therapy (ET), or who had received prior ET.
Method(s): The analysed patient population received abemaciclib 150 mg twice daily plus AI or fulvestrant per licensed indication. Effectiveness outcomes included real-world progression-free survival (rwPFS) and time to chemotherapy (rwTTC), assessed using Kaplan-Meier by treatment line.
Result(s): Median age of the 101 patients was 62 (interquartile range 55-72) years, 78 (77.2%) were post-menopausal. At abemaciclib start, 88.1% had stage IV disease; 5.0% stage III; and 6.9% unknown. The ET partner was fulvestrant in 68.3% and AI in 31.7%. Fifty patients received abemaciclib as first-line (1L) and 34 as second-line (2L) treatment; third-line cases (n=17) are not reported. Median rwPFS was 30.0 and 17.7 months for patients in 1L or 2L, respectively (Table). Of those who received abemaciclib in 1L and 2L, 13 (26.0%) and 15 (44.1%) patients, respectively, required chemotherapy in a subsequent line; rwTTC for 2L was 23.1 months. At 24 months, 27.0% of 1L and 57.0% of 2L patients had started chemotherapy. Based on time-to-discontinuation data (n=101), 54 patients discontinued abemaciclib due to: disease progression (n=16), toxicity (n=27), physician choice (n=6), or unknown/other (n=5). [Formula presented]
Conclusion(s): In these UK patients with HR+/HER2- ABC, abemaciclib with ET showed meaningful real-world clinical benefits that were consistent with findings from clinical trials. The outcomes reinforce that adding abemaciclib to ET can prolong rwTTC and delay disease progression, supporting ongoing clinical utility in UK patients with HR+/HER2- ABC. Editorial acknowledgement: Medical writing support was provided by Laura Wesley, and Sarah Birch (Rx Communications Ltd, Mold, UK), and funded by Eli Lilly. Legal entity responsible for the study: Eli Lilly and Company.
DOI: 10.1016/j.esmoop.2026.107596
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