Model-informed development of a cost-saving dosing regimen for enfortumab vedotin.

Population pharmacokinetic modelling was used to simulate a dosing regimen leading to equivalent exposure by using the published population pharmacokinetic model in the registration reports. The alternative dosing regimen was based on weight-bands derived from the established non-linear relationship between body weight and systemic exposure, and the usage of whole vials based on fixed doses to prevent spillage. Equivalent exposure compared to the approved body weight-based dosing regimen was defined as conservative equivalent boundaries of 90-111% for the calculated geometric mean ratios (GMRs) of area under the concentration-time curve and trough concentration.

The proposed alternative dosing regimen shows that drug costs and spillage of enfortumab vedotin can be reduced while maintaining an equivalent and more evenly distributed exposure in treated patients.

A weight-band based dosing regimen for each dose level of enfortumab vedotin was developed. The GMRs for all pharmacokinetic outcomes were within the predefined equivalence boundaries. In addition, a more even exposure distribution was observed across the body weight quartiles. The average costs savings across all dose levels and per weight-band were approximately 15%.

Enfortumab vedotin is an antibody-drug conjugate (ADC) that has been approved for locally advanced or metastatic urothelial cancer, as monotherapy and in combination with pembrolizumab, and has shown significant benefit in progression-free survival and overall survival for these patients. The economic burden of enfortumab vedotin hampers widespread patient access. The aim of this study was to develop a model-informed alternative dosing regimen that results in equivalent drug exposure while reducing the costs and prevent drug spillage.