OBJECTIVES: A Markov model has been adapted with local costs and epidemiological inputs in order to evaluate, from the Italian National Health Service perspective, the cost-effectiveness of pertuzumab combined to the standard trastuzumab-based regimen for the adjuvant treatment of patients with HER2-positive early breast cancer at high risk of recurrence (EU approval June 1st 2018).

METHODS: The target population is represented by patients at high risk of recurrence as defined by EU label (HR-negative or node-positive subgroups). Main clinical input is the time spent in iDFS (invasive Disease Free Survival) state, estimated by parametric extrapolations to the data observed in the pivotal trial APHINITY. Utility weights are taken from EQ-5D scores collected in APHINITY and adjusted for Italian Tariffs. The modelled adjuvant cost comprised drugs, administration and adverse events management costs. Furthermore, follow-up and applicable therapeutic cost is attributed to each Markov state.

RESULTS: Pertuzumab based regimen was associated to an increase in both QALYs and costs vs standard therapy. The estimated ICER is equal to €38,600 per QALY gained, with a chance of 90% to be the most cost-effective choice for Willingness-To-Pay (WTP) threshold of €45,000. Acquisition cost of pertuzumab is the main driver to the cost increase, but over the time this is partially offset by the prevention of BC recurrences. Cost for managing recurrences, representing 1% of total cost in the first year, grows over years, becoming the 25% of the Perjeta-based regimen costs and the 52% of the standard treatment costs, at 10 years.

CONCLUSIONS: N+ or HR- HER2+ early breast cancer is associated with higher risk of recurrence; the combination of pertuzumab to adjuvant trastuzumab-based regimen is expected to be more effective at a cost per QALY gained positioned within the most common WTP limits.