1340PEffective treatment with T-VEC monotherapy in stage IIIB/C-IVM1a melanoma of the head & neck region

Abstract Background Talimogene laherparepvec (T-VEC) is a modified herpes simplex virus, type 1 (HSV-1), which can be administered intralesionally in patients with stage IIIB/C-IVM1a unresectable melanoma. When surgery is not a treatment option in the head and neck region, i.e. due to the location or the size of the tumor, T-VEC therapy can be an elegant alternative to systemic immunotherapy. Methods 9 patients with melanoma in the head and neck region started treatment with T-VEC monotherapy at the Netherlands Cancer Institute, of which 4 are still currently on treatment. We collected data on response, adverse events (AE) and baseline characteristics. For response evaluation, we used clinical evaluation with photography, 3-monthly PET-CT’s and histological biopsies. Results Median age at baseline was 78.3 years. Of the 5 patients who stopped treatment, the median follow-up time was 9.1 months. Of these patients, 3 (60%) had a complete response (CR), 1 (20%) patient had a partial response (PR) and 1 (20%) patient showed progressive disease (PD) as their best response. ORR was 80%. Duration of response varies between 1.6-21.6 months. 2 patients developed distant metastases, 1 during T-VEC treatment and 1 after achieving a CR with a time to progression of 14.2 months. 4 patients are still on treatment today. Grade 1 AE’s occurred in all patients. Mostly, these consisted of fatigue, influenza-like symptoms and injection site pain. PET-CT and histological biopsies proved to be a clinically useful tool to evaluate treatment response for T-VEC monotherapy, confirming pCR or PD to stage IV disease requiring systemic treatment. Conclusions ORR for T-VEC monotherapy for melanoma in the head and neck region at our institute was 80% with 60% achieving a CR. This real world data on T-VEC monotherapy in stage IIIB/C-IVM1a unresectable melanoma of the head and neck region demonstrates interesting results and suggests T-VEC is an elegant alternative to systemic therapy in this select elderly and frail patient population. Legal entity responsible for the study The authors. Funding Has not received any funding. Disclosure V. Franke: Honoraria (institution), Advisory / Consultancy, Research grant / Funding (institution): amgen. M.W.J.M. Wouters: Research grant / Funding (institution): Novartis. W.J. van Houdt: Advisory / Consultancy, Research grant / Funding (institution): amgen. A.C.J. van Akkooi: Research grant / Funding (institution): Novartis; Advisory / Consultancy, Research grant / Funding (institution): amgen; Research grant / Funding (institution): BMS; Research grant / Funding (institution): MSD-Merck; Research grant / Funding (institution): Merck-Pfizer. All other authors have declared no conflicts of interest.