The cost of enfortumab vedotin wastage due to vial size—a real-world analysis

Enfortumab Vedotin (EV) is FDA-approved for advanced urothelial cancer in patients previously treated with platinum-based chemotherapy and a checkpoint inhibitor. We conducted a real-world study to determine the extent of EV wastage in a single institution and assessed the financial impact of EV wastage annually in the United States. Systematic examination of the usage and wastage of all standard-of-care EV treatments administered to urothelial cancer patients at Memorial Sloan Kettering Cancer Center (MSKCC) between 1 January 2020 and 31 December 2020 was performed. Drug wastage was calculated by subtracting the actual administered dose from the total dose in an optimal set of vials. We built a pharmacoeconomic model to assess the financial impact of EV wastage annually in the US using the January 2021 Average Sales Prices from the Centers for Medicare and Medicaid Services. Sixty-four patients were treated with standard-of-care EV, with a median of 11 doses per patient (range 1-28). Wastage occurred in 46% of administered doses (367/793), with a mean waste per dose of 2.9% (0-18%). The average drug wastage cost per patient was $3127 ($252/dose). The annual cost of EV wastage in the US is estimated to be $15 million based on wastage data from a single center in the US. In summary, EV wastage due to available vial sizes was 2.9%, which falls under acceptable thresholds. While the percentage of EV wastage is relatively low, waste-minimizing practices may reduce the financial toxicity for the individual patient and for society.