Abstract P4-16-08: A regional audit of 6-hour monitoring for administration related reactions during the first administration of subcutaneous trastuzumab

Introduction In 2012, Subcutaneous Trastuzumab (TSC) was introduced as an alternative to Intravenous Trastuzumab (TIV) for HER2+ breast cancer. The pivotal HannaH study demonstrated that TSC was non-inferior to TIV, was preferred by patients, and serious administration related reactions (ARRs) were not reported. However, the Summary of Product Characteristics (SPC) advises that patients be observed for ARRs for 6 hours post-first administration (and 2 hours post-subsequent administrations), similar to TIV. Aim To assess the frequency and tolerability of ARRs during the 6-hour observation period post first administration of TSC in patients with HER2+ breast cancer. Method: A retrospective audit of TSC was conducted in Southwest Ireland across five centers from 2014-2016. Patient charts were reviewed to record ARRs reported on the first-administration or at subsequent visit. In addition a subset of patients were interviewed regarding their recollection of ARRs with first or subsequent injections. Results: The study is ongoing having identified 192 patients. These centers have administered 2111 TSC injections in total, associated with 4998 hours of observation as per SPC. From the 385 injections given over the first two TSC administrations, 13 injections (3.4%) were associated with ARRs within 24 hours. Nine patients (2.3%) experienced injection site reactions immediately post injection, one injection site pain (0.3%), and one experienced petechiae on subsequent exposure (0.3%). Three patients experienced pyrexia and dry cough 24 hours post-injection and were hospitalized for respiratory tract infection. There were no reactions experienced between 2 and 6 hours post-first injection. There were no serious ARRs. Telephone interviews are ongoing and these results will be reported. Conclusion: ARRs related to TSC are usually immediate, mild and self-limiting. Observing patients for 6 hours post-first injection and 2 hours post-subsequent injections represents an inefficient use of healthcare resources. Citation Format: Karmali S, Hughes N, Kinneally A, Kroes J, Cook J, Killian M, Shafiq T, O9Mahony D, Bird B, O9Connor M, O9Reilly S, Galiauskas R, Murphy CG. A regional audit of 6-hour monitoring for administration related reactions during the first administration of subcutaneous trastuzumab [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-16-08.