Biosimilar Trastuzumab is Cost-Efficient Over Reference Trastuzumab for Metastatic Breast Cancer

Study findings suggest biosimilar intravenous (IV) trastuzumab-dkst is cost-efficient over reference IV and subcutaneous trastuzumab in metastatic breast cancer (J Med Econ. 2021;24(1):743-756. doi:10.1080/13696998.2021.1928515).

“Therapeutic biologics in oncology, such as targeted monoclonal antibodies, immune checkpoint inhibitors, and cell therapies have significantly advanced cancer treatment options and outcomes, however, at a significant incremental cost,” wrote Ali McBride, PharmD, MS, BCPS, The University of Arizona Cancer Center, Tucson, AZ, and colleagues.

“With the expiration of the patents of the first generation of therapeutic monoclonal antibodies in oncology, the development of biosimilar therapeutics is accelerating,” they added.

This aimed to investigate the cost-efficiency and budget-neutral expanded access of biosimilar vs reference trastuzumab with and without pertuzumab for the treatment of patients with metastatic breast cancer.

Conversion from reference IV trastuzumab monotherapy generates 1-year cost savings between $2,272,189 and $31,506,804. Conversion from subcutaneous trastuzumab monotherapy generates 1-year cost savings between $2,071,277 and $35,775,475.

In combination with pertuzumab, trastuzumab-dkst is cost-efficient in all patient weights with one-year savings over reference IV trastuzumab up to $32,662,714 and over subcutaneous trastuzumab up to $35,322,461.

Dr McBride and colleagues noted that conversion from IV trastuzumab monotherapy could provide between 3087 and 30,911 additional trastuzumab-dkst doses. These additional doses would be enough to treat 58 to 583 patients for 1 year. In addition, conversion from subcutaneous trastuzumab monotherapy could provide between 1559 and 48,598 additional trastuzumab-dkst doses, equating to treatment for 38 to 918 patients for 1 year.

In combination with pertuzumab, conversion from reference IV trastuzumab could provide from 311 to 3939 maintenance doses or 17 to 210 additional 1-year regimens for patients. Savings from conversion from subcutaneous trastuzumab could provide an additional 226 to 4782 maintenance doses or 12 to 254 1-year regimens for patients.

“This economic simulation demonstrates that biosimilar trastuzumab-dkst is cost-efficient over trastuzumab-IV and [subcutaneous] trastuzumab across all patient weights in both monotherapy and in combination with pertuzumab and paclitaxel.,” concluded Dr McBride and colleagues.

“The marked cost-savings achieved by biosimilar conversion to trastuzumab-dskt can be re-allocated to provide expanded access to additional doses or year-long regimens of trastuzumab-dkst on a budget-neutral basis,” they added.