The Economic Impact of Vial Sizes on Drug Waste of Bortezomib and Carfilzomib in Multiple Myeloma: The US Oncology Network Study

Drug waste poses a significant challenge in the field of health care, resulting in increased costs and environmental concerns. One of the primary causes of drug waste is the necessity to dispose of partially used vials due to their size and type. Single-dose vials (SDV) are commonly utilized to minimize the risk of contamination. However, the absence of various vial sizes for SDVs leads to the wastage of remaining quantities after preparing patient-specific doses. This research aims to investigate the influence of vial sizes on drug waste and cost for two oncology medications: bortezomib, which is only available in a single vial size (3.5 mg SDV), and carfilzomib, which offers multiple vial sizes (60 mg, 30 mg, and 10 mg SDVs).

Using administrative claims data for Medicare patients from 15 practices in The US Oncology Network between 2017 and 2022, we assessed the amount of drug waste and the corresponding financial impact for bortezomib and carfilzomib. To measure drug waste, we analyzed the billed units with the -JW modifier attached to paid claims. The financial impact was evaluated by utilizing Medicare's Average Sale Price (ASP) based reimbursement during the calendar quarter of the administration. We also analyzed the trends in drug waste over time for both medications and assessed the impact of the introduction of a new vial size (10 mg SDV) for carfilzomib in 2018.

The utilization of the 3.5 mg SDV of bortezomib for the preparation of patient-specific doses of 1.3 mg/m² of body surface area (BSA) resulted in the wastage of the remaining partial vial in 92.4% of the 100 685 administrations that were reviewed. On the other hand, carfilzomib, with patient- and regimen-specific doses of 20/27/56/70 mg/m² of BSA, may be prepared using a combination of different vial sizes, resulting in wastage in 66% of the 34 954 administrations reviewed. Over the period from 2017 to 2022, 30.6% of the total billed dose of bortezomib was wasted, while only 8.1% of the total billed dose of carfilzomib was wasted. Table 1 contains key measurements of drug waste for bortezomib and carfilzomib.

Table 1. Key Measurements of Drug Waste for Bortezomib and Carfilzomib

Prior to May 2018, carfilzomib was available in 60 mg and 30 mg SDVs, resulting in an average wastage of 17.2% during the preparation of patient-specific doses. However, with the introduction of the smaller 10 mg SDV for carfilzomib, patient-specific doses could be prepared using a combination of three vial sizes, reducing waste by more than 70% to 4.75% of the total billed dose and resulting in a cost savings of $7.4 million. Nevertheless, this change also led to an increase in the average number of individual vials used per administered dose, rising from 1.4 to 2.3 vials, which amounted to an additional 20 687 vials. This increase in vial usage contributes to the complexity of the admixture process and potential environmental harm.

Authors:

Puneeth Indurlal MD, MS, Vice President, Practice Operations¹;Jody Garey, PharmD, Director, Clinical Analytics and Data Science²; Jessica Neeb, MSN, RN, OCN, Senior Director, Transformation and Quality²; Lalan Wilfong, MD, MS, Senior Vice President, Value Based Care³; John Burke, MD⁴

Affiliations:

¹The American Oncology Network, Fort Myers, FL

²The US Oncology Network, The Woodlands, TX

³Thyme Care, Nashville, TN

⁴Rocky Mountain Cancer Centers, Aurora, CO