Talimogene Laherparepvec Response in Recurrent Melanoma During Corticosteroid Replacement for Immune Checkpoint Inhibitor-Induced Adrenal Insufficiency: A Case Report.

Talimogene laherparepvec (T-VEC) is an intralesional oncolytic viral therapy approved for unresectable melanoma; however, its use is generally contraindicated in immunosuppressed patients, including those receiving systemic corticosteroids. Data regarding the safety and efficacy of T-VEC in patients on physiological steroid replacement for immune checkpoint inhibitor (ICI)-induced adrenal insufficiency is limited. We report the case of a 78-year-old man with recurrent in-transit melanoma of the scalp who developed secondary adrenal insufficiency following pembrolizumab therapy requiring chronic hydrocortisone replacement. Despite ongoing physiological corticosteroid therapy, the patient was treated with intralesional T-VEC and achieved a complete clinical and histologic response without infectious complications. He tolerated treatment well, requiring stress-dose steroids only during intercurrent illness, and remains without evidence of disease at follow-up. This case suggests that physiological corticosteroid replacement may not significantly impair T-VEC efficacy or increase infectious risk. Verbal informed consent was obtained from the patient for publication of this case report and accompanying images.