Economics of alternative dosing strategies for pembrolizumab and nivolumab at a single academic cancer center

BACKGROUND: The FDA initially approved pembrolizumab and nivolumab for doses based on patient weight, but subsequently amended approval to fixed doses. We estimated savings from novel dosing strategies based on real-world patient data from a single cancer center. METHODS: We analyzed all outpatient doses of pembrolizumab and nivolumab administered at three infusion centers affiliated with our academic hospital between July 1, 2018 and Oct 31, 2018. We estimated savings from several dosing strategies with and without vial sharing between patients. RESULTS: A total of 1029 doses of pembrolizumab or nivolumab were administered for multiple cancer types. For 77% of doses, the weight-based dose was less than the fixed dose. "Dose-minimization" (DM), defined as the lesser of weight-based and fixed dose decreased nivolumab spending by 9% without affecting pembrolizumab spending. DM plus vial sharing decreased pembrolizumab spending by 19% without affecting nivolumab. The differences in savings were due to availability of multiple vial sizes for nivolumab but not pembrolizumab. DM plus vial sharing for both drugs would have saved $1.5 million USD over the 4-month study period. CONCLUSION: New dosing strategies for pembrolizumab and nivolumab can generate large savings without anticipated decrease in efficacy. Barriers include FDA dosing labels, hospital policies against vial sharing, and inaccessibility of smaller vial sizes, which are currently available in other worldwide markets.