Comparative cost savings of biosimilar and dose rounding utilization in oncology care

Introduction The exponential rise in cancer costs has led many centers to utilize dose rounding to the nearest vial size when the difference in dose is ≤10% to decrease costs. The recent approval of several biosimilar products has presented another opportunity to mitigate the rising costs of oncology care. Scarce information exists about the expected cost savings of combining dose rounding strategies (DRS) with biosimilar use (BU). We therefore assessed the cost savings of combining DRS and BU. Methods Electronic health record data for two health systems in Rhode Island were used to identify patients who received ≥1 of trastuzumab, trastuzumab-anns, bevacizumab, or bevacizumab-awwb from October 1, 2015 to September 1, 2020. Costs were estimated using Medicare drug pricing. Multivariable generalized estimating equations adjusting for age, gender, presence of metastases, dosing weight, and dose administered were used to compare costs per dose between the four exposure groups: DRS + BU, DRS only, BU only, and neither DRS or BU. Results A total of 1156 patients were administered 15,145 doses of drug. After covariate adjustment, average savings per dose was greatest in the DRS + BU group (vs. the neither DRS nor BU group); $331 for trastuzumab and $497 for bevacizumab. Conclusions Combining dose rounding with biosimilar substitution for trastuzumab and bevacizumab resulted in significant cost savings per dose and should be implemented by healthcare systems.