Extravasation of enfortumab vedotin: a case report and literature review on antibody-drug conjugates.

Enfortumab vedotin (EV) is an antibody-drug conjugate (ADC) indicated for advanced or metastatic urothelial carcinoma. We describe a case of EV extravasation in a patient with metastatic bladder cancer. The extravasation area appeared swollen without clinical evidence of acute severe toxicity. Guided by the presence of monomethyl-auristatin E (MMAE) component in EV's structure, prompt management of extravasation includes the administration of a subcutaneous injection of the enzyme hyaluronidase, along with the application of warm compresses and elevation of the affected limb. Due to EV vesicant properties, special precautions should be taken in cases of extravasation. Based on the positive outcomes observed, immediate infiltration of hyaluronidase, application of a warm compress, and limb elevation are recommended. Timely recognition of extravasation and prompt initiation of treatment help to minimise the occurrence of severe complications for patients. Further comprehensive guidelines with clear instructions for managing ADC extravasation are necessary for optimal patient care.