Abstract PO4-12-11: Patient (pt) time burden with IV vs subcutaneous (SC) administration of trastuzumab/pertuzumab (HP): A time and motion (T+M) substudy of a single arm phase II trial of adjuvant endocrine therapy plus HP for stage I HER2+ breast cancer

Abstract Background: The time required for in-clinic drug administration may have a substantial detrimental impact on breast cancer patients’ quality of life. SC drug administration, as opposed to IV, may reduce this time commitment. The purpose of this study was to estimate the relative difference in time and logistical burden between IV and SC administration of HP. Methods: We prospectively enrolled a pre-specified sub-cohort of pts participating on the ADEPT trial (NCT04569747) to this T+M substudy. The ADEPT trial is an ongoing single arm prospective phase II trial of adjuvant SC HP (for 1 yr) plus endocrine therapy for pts with hormone receptor-positive (HR+) and HER2+ stage I (pT1N0 or pT1N1mi) breast cancer. Pts eligible for ADEPT have completed primary breast surgery and are systemic therapy-naïve. Pts who received cycle 1 of loading SC HP at Dana-Farber Cancer Institute and tolerated SC drug administration were eligible and enrolled consecutively to the T+M substudy until the T+M accrual goal; accrual to the T+M substudy was mandatory for eligible pts. The T+M substudy was a single arm crossover design in which pts received 2 cycles of IV HP, followed by 2 cycles of maintenance dose SC HP. During those 4 treatment (tx) cycles, timepoints in the drug preparation and administration process were captured from the electronic medical record or flowsheets filled out by infusion nurses. The primary endpoint of the T+M substudy was total pt chair time in the infusion area (measured from start of first drug administration to end of final post-drug observation period). Exploratory endpoints included total drug preparation time and total pt tx experience time. A sample size of 22 pts was estimated to provide 86% power with 2-sided alpha 0.05 to detect a difference of 70 mins in the primary endpoint by tx arm (IV vs SC). For all endpoints, the average time across both tx cycles was calculated for each pt, and the overall mean across pts for each of IV and SC administration was computed (with standard deviation). Average times for IV vs SC administration were compared via paired Wilcoxon signed rank tests. Adjustments for multiple comparisons were not included. Results: 22 pts participated on the T+M substudy, and each had timepoints captured during 4 tx cycles (2 IV and 2 SC cycles), for a total of 88 patient-cycles analyzed overall. Pts had median age 58 yrs (range 42-83), and were 96% female, 82% White, 9% Black, 9% Asian; and 100% non-Hispanic. Comparison of time intervals for IV vs SC drug administration is shown in the Table. Mean total pt infusion chair time was 84.3 mins with IV HP, vs 22.5 mins with SC HP, for a difference of 61.8 mins shorter pt time commitment in favor of SC administration (p 0.0001). The mean total drug preparation time was significantly decreased in favor of SC administration (by 78.2 mins; p 0.0001); and the total pt tx experience time was significantly decreased in favor of SC administration (by 81.8 mins; p 0.0001). Conclusions: This prospective T+M study demonstrated that pt infusion chair time is significantly decreased with SC as compared to IV administration of HP, shortening this pt time burden by approximately one hour. SC drug administration is an approach that may help to improve and shorten the pt breast cancer therapy experience and decrease pharmacy burden. Table. SD, standard deviation Citation Format: Adrienne Waks, Noah Graham, Emily Chen, Anna Mae Frey, Victoria Attaya, Ibrahim Abbass, Anita Fung, Jesse Sussell, Patricia Cortazar, Caroline Harvey, Kenneth Almeida, Denise Leth, Wendy Chen, Jose Leone, Susan Schumer, Nabihah Tayob, Sara Tolaney. Patient (pt) time burden with IV vs subcutaneous (SC) administration of trastuzumab/pertuzumab (HP): A time and motion (T+M) substudy of a single arm phase II trial of adjuvant endocrine therapy plus HP for stage I HER2+ breast cancer 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 PO4-12-11.