Presentation (CTI)

OBJECTIVES: Pembrolizumab is a PD-1 inhibitor approved for multiple malignancies with demonstrated clinical benefit. However, its high cost may limit access in low- and middle-income countries such as Argentina. Although initially approved using a weight-based dosing (WBD) regimen of 2 mg/kg every 3 weeks, a therapeutically equivalent fixed-dose (FD) regimen of 200 mg every 3 weeks was adopted for most indications. The objective of this study is to assess the economic impact of weight-based dosing (WBD) versus fixed dosing (FD) of pembrolizumab.
METHODS: A retrospective economic evaluation was conducted using an institutional database to identify all pembrolizumab administrations at our institution between December 1, 2018, and December 31, 2025. Weight-based doses were calculated using patient body weights in clinical reports and compared with standard fixed dosing to estimate potential cost differences.
RESULTS: A total of 450 patients treated with pembrolizumab were included in the analysis. The mean body weight was 71.7 kg. In most patients, WBD resulted in lower administered doses compared with FD. Overall, implementation of WBD was associated with a 26.8% cost reduction compared with the theoretical expenditure under FD.
CONCLUSIONS: In this analysis, weight-based dosing (WBD) of pembrolizumab demonstrated greater efficiency in drug utilization compared with fixed dosing (FD). The use of WBD was associated with a lower budgetary impact, supporting its role as a resource-conscious dosing strategy for high-cost oncology treatments in resource-limited settings.