Budget Impact Analysis of Biosimilar Trastuzumab for the Treatment of Breast Cancer in Croatia

Background and Objective Breast cancer is the most common cancer in women and has considerable impact on healthcare budgets and patients’ quality of life. Trastuzumab (Herceptin®) is a monoclonal antibody directed against the human epidermal growth factor receptor (HER2) for the treatment of breast cancer. Several trastuzumab biosimilars are currently in development. In 2015, trastuzumab was the drug with the highest financial consumption among all drugs in Croatia. This model estimates the 1-year budget impact of the introduction of biosimilar trastuzumab in Croatia. Methods A budget impact model, based on approvals for trastuzumab treatment in 2015, was developed for the introduction of biosimilars. Two biosimilar scenarios were developed: biosimilar scenario 1, based on all approvals in 2015, and biosimilar scenario 2, based on approvals after February 2015 and the reimbursement of the subcutaneous formulation of trastuzumab in Croatia. Only trastuzumab-naïve patients and drug-acquisition costs were used in the model. Uptake of biosimilar was assumed at 50 %. Scenarios were calculated with price discounts of 15, 25 and 35 %. The robustness of the model was tested by extensive sensitivity analyses. Results The projected drug cost savings from the introduction of biosimilar trastuzumab range from €0.26 million (scenario 2, 15 % price discount) to €0.69 million (scenario 1, 35 % price discount). If budget savings were reinvested to treat additional patients with trastuzumab, 14 (scenario 2, 15 % price discount) to 47 (scenario 1, 35 % price discount) additional patients could be treated. Sensitivity analyses showed that the incidence of breast cancer had the highest impact on the model, with a 10 % decrease in incidence leading to an 11.3 % decrease in projected savings. Conclusion The introduction of biosimilar trastuzumab could lead to significant drug cost savings in Croatia.