Track

Case Reports

Abstract

Enfortumab vedotin (EV) is a Nectin-4-directed antibody-drug conjugate currently approved for the treatment of patients with locally advanced or metastatic urothelial carcinoma (UC). While EV has shown survival benefit compared to conventional chemotherapy, because of the expression of Nectin-4 in epidermal keratinocytes, a variety of cutaneous adverse effects have been documented. We present a case of a 53-year-old female with metastatic UC, who developed a diffuse, intensely pruritic morbilliform eruption throughout nearly her entire body that started and rapidly worsened after receiving two cycles of EV and pembrolizumab. She denied fevers or skin pain, and did not demonstrate any mucosal lesions or Nikolsky sign on physical examination. Shave biopsy from the trunk showed interface dermatitis with hydropic change and keratinocytes showing necrosis, atypia, and dyskeratosis. After enfortumab was held and topical steroid application was initiated, her rash desquamated and subsequently resolved. There have been a handful of reports describing the varied histological features of EV-related dermatitis including Stevens-Johnson syndrome/toxic epidermal necrosis (SJS/TEN) as the severest form, and we present our case to emphasize the importance of being cognizant of SJS/TEN-like histology associated with keratinocyte dysmaturation in a patient undergoing dual therapy with EV and pembrolizumab. While a mimicker of SJS from histology, the atypical clinical presentation and presence of keratinocyte dysmaturation allowed us to distinguish this unique EV-related dermatitis from SJS/TEN in order to safely maximize the superior therapeutic benefit of EV and pembrolizumab.