Factors impacting treatment with abemaciclib + endocrine therapy in high risk early-stage HR+/HER2- breast cancer patients.
Authors: Fred J. Kudrik, Stephan B. Rosenfeld, Sowjanya Reganti, Suresh V. Reddy, Rushir J. Choksi, Jeffrey Alan Scott, Anna Rui, Anubhav Sharma, Teena Sura, Lindsay Aton, Mike Gart, Ashley Lamb, Lisa Morere, Brandon Wang, Prateesh Varughese, Vikram C. Gorantla
Journal: Journal of Clinical Oncology (2025)

e12521 Background: The inhibitor of cyclin-dependent kinases 4 and 6, abemaciclib (abema), in combination with endocrine therapy (ET) is indicated for the adjuvant treatment of breast cancer (bc) patients (pts) with hormone receptor positive (HR+), human epidermal growth factor receptor-2 negative (HER2-), node-positive, early bc at a high risk of recurrence. High risk of recurrence is defined as pts with &gt;4 positive lymph nodes, or 1-3 positive lymph nodes with either grade 3 disease or a tumor size &gt; 5cm either pre-operatively or at surgery. This real-world study sought to understand the factors for whether pts receive abema+ET among early-stage high risk HR+/HER2- bc. Methods: This was a retrospective, observational analysis of data from pts in the IntegraConnect PrecisionQ real-world de-identified database. The study included adults (age ≥18 years) with HR+/HER2- bc at high risk of recurrence who initiated adjuvant therapy between January 1, 2023 and September 30, 2024 with follow-up through November 30, 2024. Pts were assessed to see whether age of pt, eastern cooperative group status (ECOG), race, volume of pts treated by a provider, or risk grouping of pt impacted whether a pt received adjuvant abema+ET. Data are presented using descriptive statistics and comparisons were performed using chi-squared analyses. Results: Of the 1267 pts with HR+/HER2- bc at high risk of recurrence who initiated adjuvant therapy included in the analysis, most were female (96.7%) and white (56.0%) with a median age of 63 [IQR ]. Among eligible pts, 45% received abema+ET. Pts who &gt; 65 years of age at diagnosis (N = 557) 34.8% received abema+ET whereas pts &lt; 65 years of age at diagnosis (N = 710) 53.8% received abema+ET (p &lt; 0.01). Among pts with ECOG &lt; 1, the use of abema+ET was 47.8% (N=1029), while pts with ECOG&gt;2, abema+ET use was 29.9% (N=67) (p &lt;0.01). Among White pts use of abema+ET was 46.1% (N=709), whereas among Black/African American pts use of abema+ET was 51.9% (N=108) (p&gt;0.05). Among pts with &gt; 4 positive nodes (N = 602) 49.7% received abema+ET, 1-3 positive nodes with grade 3 and tumor size of &gt; 5cm (N = 60) 51.7% received abema+ET, 1-3 positive nodes with grade 3 and tumor size &lt; 5cm (N = 294) 35.0% received abema+ET, and 1-3 positive nodes with tumor size &gt; 5cm (N = 311) 46.0% received abema+ET (p &lt; 0.01). Regarding pts who had &gt;4 nodes, no notable differences were found abema+ET use based on tumor size. Of 337 providers who saw &lt;5 pts (N = 628) 37.9% prescribed abema+ET, among 72 providers who saw 5-10 pts (N = 501) 45.1% prescribed abema+ET and among 10 providers who saw &gt;10 pts (N = 138) 51.4% prescribed abema+ET (p&lt;0.01). Conclusions: Pts with HR+/HER2- bc at high risk of recurrence who initiated adjuvant therapy were more likely to receive abema+ET if they were younger (&lt; 65 years of age), had better performance status (ECOG &lt;1), had &gt;4 positive nodes, 1-3 positive nodes with a tumor &gt;5cm, or were treated by a provider with &gt;10 high risk pts.