Induced Vitiligo due to Talimogene Laherparepvec Injection for Metastatic Melanoma Associated with Long-term Complete Response

Abstract

Talimogene laherparepvec (T-VEC) (Imlygic, Amgen) is the first oncolytic virus approved for use in therapy for metastatic melanoma. T-VEC provides a treatment option for patients with limited metastatic disease. T-VEC is a genetically modified, live, attenuated herpes simplex virus type 1 designed to replicate in tumour cells and promote an enhanced anti-tumour response (1) T-VEC is administered by injection into cutaneous, subcutaneous or nodal lesions, which are visible and/or palpable and/ or visualized by ultrasonography (2). Other local management options have been used to control metastatic disease in stage IIIB, but almost all have shown only a local effect and rapid disease relapse (3, 4). With T-VEC, responses occurred in injected and uninjected lesions, including a greater than 50% decrease in size in 15% of uninjected visceral lesions. The appearance of vitiligo has been described as an adverse event after administration of immune checkpoint inhibitors (5, 6). It has been reported as a marker of activity of the drug and long-term results, inducing clinicians to use it as a predictor of drug response (7). A T-VEC phase II study has reported 85% adverse events, all of which were grade 1 or 2. The appearance of vitiligo has been described in 3 patients out of 50 (8), although no details regarding duration and appearance have been reported.