The subcutaneous formulation of trastuzumab is a potential alternative to intravenous trastuzumab in people for whom trastuzumab treatment is appropriate and offers a quicker, less invasive mode of administration. Patient convenience, patient preference for the route of administration, and medical resource use is being assessed in the PrefHer trial (ClinicalTrials.gov identifier: NCT01401166).
A comment article published with the HannaH study discussed the convenience of subcutaneous administration of trastuzumab in terms of the benefit to people of receiving treatment at home or in the community, and the potential savings in hospital resources. The commentators note that these benefits may not be realised if trastuzumab is combined with other drugs given intravenously, such as taxanes. Savings may also be offset if women receiving subcutaneous trastuzumab are more likely to be admitted to hospital to manage adverse effects, as was seen in the HannaH study. In addition, some women may prefer to receive treatment in a day hospital setting where they can access other support, while some women may prefer to receive treatment at home.
The patent for intravenous trastuzumab expires in 2014 and it is possible that biosimilar products will become available then. However, information on whether such products are in development, their likely licensed route of administration and cost is not available at present.
Local decision makers will need to consider the available evidence when making decisions about using subcutaneous trastuzumab, in the setting of their local care pathways and usual trastuzumab-containing treatment schedules, and local patients' preferences regarding whether they prefer to be treated at home or in a day hospital. The likely benefits of its use will need to be balanced against the possible risks and the absence of direct patient-oriented outcomes in early breast cancer, and the absence of phase III studies in metastatic breast cancer.
The manufacturer has used data from the Quality and Outcomes Framework, Hospital Episodes Statistics and the National Cancer Intelligence Network to estimate the likely potential use of subcutaneous trastuzumab. It estimates that in the UK in 2012 there were about 5500 people with early-stage HER2-positive breast cancer and about 2200 people with HER2-positive metastatic breast cancer that was suitable for trastuzumab treatment. Using modelling derived from its market research data, which takes account of the distribution of patient weight (and hence the costs of intravenous trastuzumab), and assuming no vial-sharing for the intravenous product, the manufacturer estimates that treating all these people with subcutaneous trastuzumab rather than intravenous trastuzumab would lead to total UK drug cost savings of about £12.5 million over 18 cycles of treatment for early breast cancer and about £4.7 million over a mean treatment duration of 17.2 cycles for metastatic breast cancer (Roche Products Limited: personal communication February 2013). Local decision makers will need to estimate the potential savings for their organisations, because this depends on the weight of patients treated locally and hence the doses and numbers of vials of intravenous trastuzumab used.