IntroductionAdjuvant trastuzumab is a standard of care in the treatment of Human Epidermal growth factor Receptor 2 (HER2) positive early breast cancer (eBC). Initially trastuzumab could only be administered intravenously (IV), however since 2013, a subcutaneous (SC) formulation with comparable efficacy and safety profile is available and preferred by patients. Trastuzumab SC does not require pharmacy preparation and has shorter administration time. The objective of this study was to estimate the economic efficiency of the SC formulation of trastuzumab by assessing the economic benefits of actual SC-driven process changes at one single Swedish healthcare institution.MethodsThis study analyzes changes in trastuzumab administration practice after the SC formulation was introduced at the Karolinska University Hospital. Process changes were identified and introduced in order to capitalize on the inherent work efficiency benefits of the SC formulation. Actual hospital data for 2015 were used to quantitatively estimate the annual economic impact of the changes. It encompassed administrative (i.e. non-medical) data of 178 newly diagnosed HER2-positive eBC patients and a total of 2,769 SC administrations. Realized economic benefits were expressed in hours saved by nurses, direct monetary cost savings and potential infusion fee revenue that could be earned through infrastructural revenue gains.ResultsIn 2015, the replacement of IV infusion to SC administration generated total time savings of more than 1,100 hours, and led to direct monetary cost savings of 603,000 EUR. It unlocked a capacity gain of 1–2 additional administrations daily within the existing facility infrastructure. Given the current remuneration structure per administration, this revenue gain translated into an incremental revenue potential of up to 3 million EUR.ConclusionData from this study showed that the shift from trastuzumab IV to SC formulation resulted in significant economic effects in terms of departmental resources related to time, direct monetary cost savings, and infrastructural revenue gains.