Introduction: Enfortumab vedotin is an antibody-drug conjugate used in patients with pretreated advanced urothelial carcinoma. Patients with human immunodeficiency virus were excluded from clinical trials conducted with this agent. Efficacy and safety of enfortumab vedotin has not been established in this patient population.
Case report: A patient with a long-standing diagnosis of human immunodeficiency virus and an undetectable viral load on antiretroviral therapy was diagnosed with metastatic upper tract urothelial carcinoma. Following disease progression on platinum-based chemotherapy and pembrolizumab, he was initiated on therapy with enfortumab vedotin.
Management & outcome: The patient developed significant toxicity shortly after initiation of enfortumab vedotin. His treatment was subsequently changed to docetaxel chemotherapy and he developed similar significant toxicity. Upon changing his antiretroviral therapy regimen, he was rechallenged with enfortumab vedotin and was able to tolerate it without dose-limiting toxicity, ultimately achieving a partial treatment response.
Discussion: This case describes use of enfortumab vedotin in a patient with human immunodeficiency virus, which has not previously been reported. It also underscores the importance of careful medication reconciliation in patients receiving enfortumab vedotin and antiretroviral therapy.
Keywords: Enfortumab vedotin, urothelial carcinoma, HIV, antiretroviral therapy, drug interaction.