Subcutaneous Trastuzumab: A Review in HER2-Positive Breast Cancer.

A subcutaneous (SC) formulation of trastuzumab, a potent humanized anti-Human Epidermal growth factor Receptor 2 (HER2) receptor monoclonal antibody, with a recombinant hyaluronidase (Herceptin Hylecta™; Herceptin®) is indicated in the USA and EU for the treatment of HER2-positive breast cancer. In the phase III pivotal HannaH trial, SC trastuzumab was noninferior to the standard intravenous (IV) formulation of trastuzumab with respect to trough drug concentrations and pathological complete response in patients with HER2-positive early breast cancer. Other clinical outcomes, including event-free survival and overall survival rates, were generally similar between the formulation groups. SC trastuzumab had a manageable tolerability profile in patients with HER2-positive early or metastatic breast cancer, with the safety profile being generally similar to that of the IV formulation. In the phase III PrefHER and MetaspHER trials, more patients preferred SC over IV trastuzumab and more healthcare professionals expressed satisfaction with the SC formulation. Relative to IV trastuzumab, SC trastuzumab offers a quicker and more convenient dosage regimen, thereby potentially improving patient convenience, providing economic benefit and optimizing the use of medical resources. Thus, given the high preference for SC trastuzumab and its generally similar efficacy and tolerability profile to that of the IV formulation, SC trastuzumab is the preferred treatment of choice in patients receiving trastuzumab for the treatment of HER2-positive early or metastatic breast cancer.