High response rates for T‐VEC in early metastatic melanoma (stage IIIB/C‐IVM1a)

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 (EMA label). The phase 3 OPTiM registration study showed an overall response rate (ORR) of 26%. Since December 2016, 48 eligible patients started treatment at the Netherlands Cancer Institute. We included 26 patients in this study with a follow up time ≥6 months, reporting Overall Response Rate (ORR), Disease Control Rate (DCR), Adverse Events (AE), prior treatment for melanoma and baseline characteristics, documented in a prospectively maintained database. In house developed treatment protocol consists of clinical evaluation, periodic PET‐CT and histological biopsies for response evaluation. Median follow‐up was 12.5 months. Of 26 patients, 16 (61.5%) had a Complete Response (CR) as their best response. Seven (26.9%) patients had a Partial Response (PR) as their best response, 1 (3.8%) patient Stable Disease (SD) and 2 (7.7%) patients Progressive Disease (PD). Best ORR was 88.5%. DCR was 92.3%. Grade 1–2 AEs occurred in all patients. Mostly, these consisted of fatigue, influenza‐like symptoms and injection site erythema. All patients underwent prior treatment. Prior treatment did not influence response or toxicity of T‐VEC. Best ORR for T‐VEC monotherapy at our institute was 88.5% with 61.5% achieving a CR. This prospective study for T‐VEC in early metastatic (stage IIIB/C‐IVM1a) melanoma demonstrated superior results to the phase 3 OPTiM study and confirms the role of oncolytic immunotherapy for melanoma. What's new? Talimogene laherparepvec (T‐VEC) is a modified herpes simplex virus, type 1 (HSV‐1), which is registered for the treatment of stage IIIB/C‐IVM1a unresectable locally advanced melanoma. Here the authors evaluated the response to this drug in 26 patients with a follow up longer than 6 months. They demonstrate promising response rates, with 61.5% of their treated patients achieving a CR. This indicates a strong potential of this novel drug in the rapidly developing field of immunotherapeutic treatment of melanoma.