Evaluation of Talimogene Laherparepvec for the Treatment of Advanced Nonmelanoma Skin Cancers

Abstract Introduction Talimogene laherparepvec (T-VEC) is an intralesional, injectable oncolytic herpes virus that is FDA-approved to treat Stage III-IV melanoma. The utility of T-VEC for nonmelanoma skin cancers (NMSC), including Merkel cell carcinoma (MCC) and squamous cell carcinoma (SCC), as well as its use with concurrent immune therapy (IO), is poorly defined. The purpose of this study is to evaluate outcomes of T-VEC for MCC and SCC with and without concurrent immune therapy. Methods This retrospective study included patients at a single institution with MCC or SCC and treated with T-VEC between May 2016 and May 2023. Abstracted cohort data were reported using descriptive statistics. Results Ten MCC and three SCC patients were eligible. Four MCC patients and all three SCC patients received concurrent pembrolizumab. Overall, six patients achieved complete response (CR), one had partial response (PR), and six had progressive disease (PD). Of the six patients who achieved CR, two recurred at 8 and 56 months. Those without recurrence had a durable response at a median follow-up of 25 months. Conclusions Our initial experience with a small, single-institution cohort demonstrated tumor response to intralesional T-VEC with or without immunotherapy in some patients with NMSC. Nearly 50% of participants had a complete response; two-thirds of responders remained relapse-free at the time of follow-up. Some observed responses are not attributable to T-VEC alone due to high usage rates of IO. Future work should expand to larger cohorts and focus on its use with and without immune therapy.