Cost-effectiveness of dose reduction of monoclonal antibodies.

e13531 Background: Monoclonal antibodies (mAbs) are being increasingly used for many diseases but can be cost prohibitive. Hematology Oncology Pharmacy Association (HOPA) has recommended rounding mAbs to the nearest vial size within 10% of the prescribed dose 1 . Previous work using pharmacokinetic simulations with reduced dosing schedules resulted in $1.00B savings with Trastuzumab alone 2 , and about 11-28% of total cost savings when expanded to several other mABs 3 . Methods: Cerner EMR at Stony Brook University Hospital was queried to identify patients who received infliximab, rituximab, and trastuzumab from November 2019 to November 2024. The doses of each medication were reduced by 5% or 10%, without overlap, to the nearest vial size, to create hypothetical doses and number of vials that would be required. Prices for each drug were obtained from the Stony Brook University Hospital Pharmacy Department and costs were calculated as: actual cost and cost with dose reductions of 5% or 10%. Data was analyzed to determine the financial benefits. Results: 7,306 patients were identified with a combined total of 41,780 vials used. The drug distribution was: 17,441 infliximab, 7,043 infliximab DYYB, 9,813 rituximab (10mL vials), 1,086 rituximab (50mL vials), 6,397 trastuzumab. After hypothetical dose reductions of 5% or 10%, a total of 4,889 vials and $1,269,589 were saved. See table 1 for full results. Conclusions: The impressive savings of over $1 million in a span of five years, at a single institution, using only four mAbs underscores the significant potential of small dose reductions. If these calculations were applied across all mAbs, some of the financial burden placed on patients and institutions could be alleviated. The data posed here, as well as in similar studies, emphasizes the potential for considerable cost savings while still adhering to clinical practice dosing recommendations. 1. Bott, A. M. (2017). Dose rounding of biologic and cytotoxic anticancer agents . Dose Rounding of Biologic and Cytotoxic Anticancer Agents A Position Statement of the Hematology/Oncology Pharmacy Association. 2. Hsieh P-H, Kacew AJ, Dreyer M, et al. Alternative trastuzumab dosing strategies in HER2-positive early breast cancer are associated with patient out-of-pocket savings. Nature News. March 14, 2022. 3. Heine R ter, Heuvel MM van den, Piet B, et al. A systematic evaluation of cost-saving dosing regimens for therapeutic antibodies and antibody-drug conjugates for the treatment of lung cancer - targeted oncology. SpringerLink. April 21, 2023. Cost savings stratified by drug. Drug Total Cost per vial Vials saved with 5% or 10% dose reductions Cost savings with 5% or 10% dose reductions Infliximab 100mg 17,441 $187.87 1,812 $340,420 Infliximab- DYYB 100mg 7,043 $88.39 753 $66,557 Rituximab 10mg/mL 10mL 9,813 $82.03 1,459 $119,681 Rituximab 10mg/mL 50mL 1,086 $441.10 0 $0 Trastuzumab 150mg 6,397 $858.88 865 $742,931 41,780 4,889 $1,269,589