Abstract PS3-11-08: Subcutaneous pertuzumab and trastuzumab fixed-dose combination versus dual intravenous pertuzumab and trastuzumab or subcutaneous trastuzumab plus intravenous pertuzumab in HER2-positive breast cancer adjuvant therapy: A time and

Abstract Background: The fixed-dose combination of pertuzumab (P) and trastuzumab (H) for subcutaneous injection (PH FDC SC) significantly reduces drug preparation and administration time compared to intravenous (IV) formulations. However, real-world time efficiency data comparing PH FDC SC with dual IV P-H (P-H IV) and sequential SC H plus IV P (H-SC + P-IV) in HER2-positive breast cancer (HER2+ BC) are limited. Methods: This prospective observational study comprises two components: a cohort study and a patient (pt) survey. HER2+ BC pts receiving P plus H therapy and their healthcare professionals (HCPs) were recruited from a day-care unit at the Cancer Hospital of Shandong First Medical University. In the cohort study, administration records were divided into five groups by the route of administration and venous access (peripheral intravenous catheter [PIVC] or implantable venous access port [IVAP]). The groups are as follows: PH FDC SC, H-SC + P-PIVC, H-SC + P-IVAP,P-H PIVC and P-H IVAP. The survey encompassed three groups: PH FDC SC, H-SC + P-IV, and P-H IV. Time metrics were collected during cycles 7 through 18. Pt time included SC injection, IV infusion, and observation time. HCP time included drug preparation, SC injection, IV line setup/infusion, and observation time. Observation time was additional to total time. The total time differences and percentage time savings were analyzed. Pt preference questionnaires were collected. Results: The cohort study included 100 administration records from 14 pts receiving PH FDC SC, 100 records from 13 pts receiving H-SC + P-IV, and 100 records from 13 pts receiving P-H IV. H-SC + P-IV records were further categorized into H-SC + P-PIVC (n=29) and H-SC +P-IVAP (n=71), while the P-H IV records were divided into P-H PIVC (n=46) and P-H IVAP (n=54). The survey included 137 pts (PH FDC SC vs. H-SC +P-IV vs. P-H IV: 24 vs. 13 vs. 100). The PH FDC SC group demonstrated significant reductions in both patient and HCP total times compared to all IV-containing regimens (all p<0.001), with absolute time savings exceeding 3000 seconds and relative reductions of 78-89%. Observation time remained consistent across groups (Table 1). Questionnaire data revealed significantly higher preference for PH FDC SC in convenience-related domains including procedure time reduction, privacy protection, and venous access avoidance (all p<0.001). Conclusions: This real-world time-motion study demonstrates that PH FDC SC significantly reduces pt treatment burden and healthcare resource utilization in HER2+ BC adjuvant therapy. Pt preference data strongly favored PH FDC SC across convenience dimensions. These findings support PH FDC SC implementation as a favorable option in day-care settings. Citation Format: Y. Meng, A. Huang. Subcutaneous pertuzumab and trastuzumab fixed-dose combination versus dual intravenous pertuzumab and trastuzumab or subcutaneous trastuzumab plus intravenous pertuzumab in HER2-positive breast cancer adjuvant therapy: A time and motion study in a lean operating day care oncology unit in China [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 PS3-11-08.