Abstract PS5-08-24: Impact of Intermittent Fasting on Biomarkers of Inflammation and Health-related Quality of Life: A Feasibility Trial for Women with HR+/HER2- Early Breast Cancer

Abstract Background: Within one year of starting adjuvant endocrine therapy (AET), the majority struggle to return to pre-cancer weight. At least 25-30% of women report a weight gain of 10 pounds or more1,2. Previous reports suggested that weight gain occurred in 14.7% of AET users compared to 6.3% of the controls3 and a weight gain of 10 pounds in at least 27% of the women4. Additionally, 61% of participants kept the weight they had gained, while only 12% lost weight4. The Intermittent Fasting (IF) Study is a Phase II, single-arm, feasibility trial examining the impact of intermittent fasting (IF) on biomarkers of inflammation and the Functional Assessment of Cancer Therapy-Endocrine Symptoms (FACT-ES) in women with ER-positive and HER2-negative early breast cancer who are starting AET. Methods: Patients with stages I-III, ER+, and HER2-negative breast cancer completed definitive surgery, +/- chemotherapy and radiation, and patients who started AET within 12 weeks of trial enrollment are eligible. Other criteria include a body mass index (BMI) of ≥25, an ECOG performance status of 0-1, adequate organ function, and agreement to biomarker testing (IGF, IL-6, Glucose, CRP, adiponectin, fasting lipids, and markers of epigenomics (H3K27ac)5-7. Exclusion criteria included a history of diabetes, other diseases with fluctuations in blood sugar, dizziness, vertigo, pregnancy, breastfeeding, and heavy alcohol use as determined by the treating providers. Following consent, all subjects will receive instructions on the 14-hour IF study for six months (14-hour fasting period after dinner and 10-hour eating period), with monthly nutritional counseling. Anthropometric measures, the FACT-ES surveys8, and biomarkers will be collected at baseline and 6 months. A total of 20 subjects will be accrued over 36 months for this study. The primary objective is to evaluate the proportion of subjects who adhere to at least 80% of the IF instructions, i.e., follow the IF schedule, on average, for at least eight out of ten days throughout the six-month intervention period. Secondary endpoints include anthropometric measures and the FACT-ES surveys, which were administered at baseline and 6 months after the conclusion of the intervention. Biomarkers will be collected at the study entry and conclusion. Mixed-effects models will be used to analyze longitudinal data. The study was approved on May 16, 2024, and enrollment began on July 31, 2024. At the time of this submission, a total of 81 patients had been prescreened, with 13 consenting (8 accrued and 5 withdrawn). Clinical Trial Identification. NCT06106477 Short Title: Intermittent Fasting Study. Sponsor: David Uihlein Foundation Citation Format: S. Kamaraju, Y. Cheng, L. N. Chaudhary, S. N. Tarima, H. N. Phuntling, P. Jessica, L. Choppavarapu, H. Alison, D. Ashley, V. Jin. Impact of Intermittent Fasting on Biomarkers of Inflammation and Health-related Quality of Life: A Feasibility Trial for Women with HR+/HER2- Early Breast Cancer [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS5-08-24.