Enfortumab Vedotin–related Cutaneous Toxicity and Radiographic Response in Patients with Urothelial Cancer: A Single-center Experience and Review of the Literature

Enfortumab vedotin (EV) is an antibody-drug conjugate approved for the treatment of refractory advanced urothelial cancer. Cutaneous toxicity is well described but has not been correlated with response. In this retrospective single-center study, data from patients treated with more than one dose of EV between December 2017 and June 2022 were analyzed. Of 56 patients with a median age of 69 yr, 41 (73.2%) were male and 27 (48.2%) had any-grade skin toxicity. For all 51 patients evaluable by physician-assessed Response Evaluation Criteria in Solid Tumors (RECIST) criteria, the response rate was 41.2%. For those with cutaneous toxicity, the response rate was 57.7%; for those without cutaneous toxicity, it was 24.0% (p = 0.0145). All three patients with complete response experienced cutaneous toxicity, and two of these responses remain durable 5 and 24 mo off EV. The median starting weight and body mass index (BMI) were, respectively, 80.86 kg and 26.53 kg/m² among patients with cutaneous toxicity, and 69.37 kg and 23.29 kg/m² in patients without (p = 0.0129 and 0.0014, respectively). In this small dataset, EV-related cutaneous toxicity was more common in patients with higher weight and BMI at baseline, and was associated with disease response. Confirmation in prospective trials may confirm this association and lead to an important clinical biomarker of response. Patient summary: We evaluated patients with urothelial cancer who were treated at our institution with enfortumab vedotin (EV). We found that patients who experienced the common side effect of any type of skin toxicity, such as rash or itching, were more likely to have improvement in their cancer from EV treatment than those who did not experience skin toxicity. Patients with higher weight and body mass index when starting EV tended to have more skin toxicity. We conclude that presence of skin toxicity might help doctors make decisions about how to manage the care of patients with EV in the future.