Biomarkers of Response to Anti-NECTIN4 Antibody-Drug Conjugate Enfortumab Vedotin in Urothelial Cancer

Initial studies indicated that NECTIN4 expression is widespread in metastatic urothelial cancer (mUC), which led to approval of the anti-NECTIN4 antibody-drug conjugate (ADC) enfortumab vedotin (EV) for unselected patients with mUC. However, the recent literature suggests that there has been overestimation of membranous NECTIN4 expression in UC, which is a prerequisite for EV binding. It is well established from the development of Her2-targeting ADCs that treatment response is strongly dependent on membranous expression level of the relevant target antigen. In this context, it has been demonstrated that membranous NECTIN4 expression correlates with EV responses and outcomes. Another promising biomarker could be NECTIN4 copy number alteration, a genomic alteration that occurs in approximately 25% of mUC cases, which is associated with strong membranous NECTIN4 expression. Patients with NECTIN4 amplification exhibit an objective response rate of >90% to EV monotherapy and long-term survival. Given the heterogeneous expression of NECTIN4 in UC, future biomarker research is essential for the development of biomarker-driven mUC treatment strategies to further improve outcomes for patients with mUC. PATIENT SUMMARY: We reviewed current evidence on biomarkers for predicting response to enfortumab vedotin (EV) treatment for metastatic urinary tract cancer (mUC). Studies to date have shown that patients with high levels of the protein NECTIN4 on their cancer cells respond well to EV. This information has the potential to guide future treatment strategies for mUC.