Abstract PO2-01-09: Patient preferences for CDK4/6 inhibitor treatments in HR+/HER2− early breast cancer: a discrete choice survey study

Abstract Background: Patients (pts) with stage II/III HR+/HER2− early breast cancer (EBC) are at risk of recurrence that persists over years. The addition of a CDK4/6 inhibitor (CDK4/6i) to adjuvant endocrine therapy (ET) was investigated in monarchE, evaluating abemaciclib (ABE) in lymph node (LN)+ high-risk pts, and NATALEE, using ribociclib (RIB) in stage II/III disease, including pts with N0 disease. ABE was FDA approved in this indication in 2021, while NATALEE recently reported statistically significant iDFS results. Both efficacy and tolerability are relevant for pts treated in a curative setting. This prospective study evaluated the extent pts with EBC value different treatment (tx) attributes and how these may translate into preferences between the two CDK4/6i in the US. Methods: A web-based discrete choice experiment survey was conducted among pts with EBC between Jan and May 2023 before NATALEE results were available. Eligible pts were adult women in a US clinical practice setting with self-reported stage II/III HR+/HER2− EBC +/- prior chemotherapy receiving only adjuvant ET at the time of survey, who completed curative surgery 1-3 years ago. Pts selected the scenario that best reflected their preferences from a series of choice cards, each displaying a pair of hypothetical tx profiles. A total of 8 attributes related to efficacy (5-year iDFS), adverse events (AEs), monitoring requirements, tx duration, and schedule were included (Table 1). Attributes were included based on an initial pilot qualitative assessment that selected efficacy and safety attributes most relevant to pts, clinical input, and differentiating features between CDK4/6i. A conditional logit regression model was used to estimate preference weights and relative importance (RI) of each attribute. Utility scores, summarizing overall preference for CDK4/6i tx profiles, were estimated from the model, and various scenarios were tested. Subgroup analyses by menopausal status and BC stage will be presented. Results: 409 pts participated in the survey (median age, 53 years; White/Black/other race, 59%/23%/18%; BC stage II/III, 48%/52%; employed, 38%). Pt preferences for attributes that significantly impacted tx decision, in order of high to low RI, were higher efficacy (iDFS), lower risk of diarrhea, lower risk of fatigue, shorter tx duration, and lower risk of venous thromboembolic events. Attributes based on monitoring or schedule, including number of blood tests, number of EKGs, and tx schedule, did not affect tx choice (Table 2). Overall utility scores were consistently higher for reconstructed tx profiles that resembled RIB features, including under conservative scenarios where efficacy of RIB was assumed to be equivalent or lower than that of ABE. Conclusions: This study showed that, driven by strong preference for lower risk of AEs, pts with HR+/HER2− EBC prefer tx profiles that more closely resemble the clinical experience of receiving RIB. These pt preferences are important for shared decision making when discussing the addition of a CDK4/6i to adjuvant tx for eligible pts with HR+/HER2− EBC. Discrete Choice Experiment Attributes and Levels Estimated Preference Weight and Relative Importance Citation Format: Erica Mayer, Mary Lou Smith, Annie Guerin, Dominick Latremouille-Viau, Nisha C. Hazra, Yan Meng, Wendi Qu, Remi Bellefleur, Vaidyanathan Ganapathy, Liz Santarsiero, Robert Morlock, Maryam Lustberg. Patient preferences for CDK4/6 inhibitor treatments in HR+/HER2− early breast cancer: a discrete choice survey study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-01-09.