An economic evaluation of vial sharing of expensive drugs in automated compounding

Background Manual compounding of expensive cytotoxic drugs often leads to drug wastage, due to residual product in vials not being used. Aim To determine the cost savings that can be achieved by implementing an automated compounding process with a vial sharing strategy, instead of manually compounding drugs. Method The drug wastage during automated compounding was compared with that of three simulation scenarios using manual compounding, in a general teaching hospital. All automatically compounded preparations of rituximab, pemetrexed, bevacizumab, and trastuzumab from September 2019 and up until February 2020 were included. A vial sharing strategy was implemented during the automated compounding process (scenario 1). In this scenario, all residual drugs could be reused for up to seven days. Two of the simulation scenarios for manual compounding were executed using a batch compounding strategy, for an entire working day (scenario 2), and twice a day (scenario 3). The third manual compounding simulation was executed without making use of a batch compounding strategy (scenario 4). Results There was no drug wastage during automated compounding with vial sharing (scenario 1). The cost of drug wastage for 1001 preparations, over a period of six months for rituximab, pemetrexed, bevacizumab, and trastuzumab combined, were € 34,133 for scenario 2, € 46,688 for scenario 3, and € 88,255 for scenario 4. The estimated total cost savings between 2017, when the compounding robot was commissioned, and 2021, was more than € 280,000. Conclusion Vial sharing of expensive drugs during automated compounding can prevent drug wastage, resulting in an economic and environmental advantage as opposed to manual compounding.