Impact of Relative Dose Intensity of Enfortumab Vedotin for Advanced Urothelial Carcinoma.

Background/aim: The impact of enfortumab vedotin (EV) dose reduction and/or interruption on its efficacy for advanced urothelial carcinoma (UC) is unclear.

Patients And Methods: We retrospectively analyzed consecutive patients with advanced UC who received EV after the failure of platinum-based chemotherapy and immune checkpoint inhibitors from December 2021 to June 2024. Patients were categorized into three groups based on the calculated relative dose intensity (RDI): RDI<50%, RDI ≥50 to <80%, and RDI ≥80%.

Results: A total of 26 patients (male, n=15; median age, 72 years) were enrolled. The RDI was categorized as follows: ≥80% (n=13; 50.0%), ≥50 to <80% (n=7; 26.9%), and <50% (n=6; 23.1%). There were no marked differences in the overall response (p=0.921) or disease control rates (p=0.859) among the three groups categorized by the RDI. A log-rank test revealed no significant differences in either the progression-free survival (p=0.309) or the overall survival (p=0.704) according to RDI. There were no marked differences in the incidence of any-grade adverse events (AEs) (p=0.405) or grade ≥3 AEs (p=0.018) according to RDI. There were significant differences in the incidence of any-grade cutaneous AEs (p=0.038) and grade ≥3 cutaneous AEs (p=0.007) according to RDI. A multivariate analysis revealed that ECOG PS≥2 (p=0.009) and mixed UC (p=0.011) were independently associated with the prognosis.

Conclusion: Despite frequent dose reductions and interruptions required to manage treatment-emergent AEs during EV therapy, these adjustments did not significantly impair the drug's efficacy in patients with advanced UC.