Cost-effectiveness of pertuzumab and trastuzumab biosimilar combination therapy as initial treatment for HER2-positive metastatic breast cancer in Singapore.

Although trastuzumab biosimilar reduced the cost of the pertuzumab combination regimen, the ICER remained high and was not cost effective in Singapore's context. As pertuzumab contributed 80% of the overall combination treatment cost, price reductions for pertuzumab will be required to improve the cost-effectiveness of combination treatment to an acceptable level.