Genomic Biomarkers Associated with Enfortumab Vedotin Outcomes for Patients with Advanced Urothelial Carcinoma: Analysis of UNITE Study Data.

Enfortumab vedotin (EV) is used as monotherapy or combined with pembrolizumab in advanced urothelial carcinoma (aUC), but biomarker data associated with EV outcomes are limited. We identified 170 patients in the UNITE study who received EV monotherapy and had molecular biomarker data available. Outcomes for groups with and without a particular biomarker were compared using logistic regression (unadjusted) for the objective response rate (ORR), and a log-rank test and Cox proportional-hazard models (CPHMs) for progression-free survival (PFS) and overall survival (OS) from EV initiation. Molecular biomarkers were also evaluated in separate multivariable analyses using CPHMs that accounted for clinical characteristics. Median patient age was 70 yr; 78% of the cohort were male and 65% had pure UC histology. Median PFS was shorter for patients with CDKN2A alterations (4.6 vs 6 mo; p = 0.024) and for patients with CDKN2B alterations (4.4 vs 6 mo; p = 0.008). Median OS was longer for patients with high tumor mutational burden (13.6 vs 8.3 mo; p = 0.014). ORR was higher for patients with TSC1 alterations (87% vs 51%; p = 0.018). In multivariable analyses, CDKN2A and CDKN2B alterations were associated with inferior median PFS. This multi-institutional retrospective study of patients with aUC identified potential biomarkers associated with EV monotherapy outcomes that should be further investigated. PATIENT SUMMARY: We investigated genetic changes in urinary tract tumors that might be associated with response to enfortumab vedotin (EV) treatment in patients with advanced disease. Survival after EV treatment was longer for tumors with a higher number of mutations than for tumors with fewer mutations. However, mutations in two genes (CDKN2A and CDKN2B) were associated with worse outcomes after EV treatment. These findings will not affect current clinical practice, but should be investigated further in future studies.