The landscape of melanoma treatment has undergone a dramatic revolution in the past decade. The use of oncolytic viruses (OVs) represents a novel therapeutic approach that can selectively infect and lyse tumor cells and induce local and systemic antitumor immune responses. As the first OV approved by the Food and Drug Administration (FDA) for melanoma treatment, talimogene laherparepvec (T-VEC), a genetically modified herpes simplex virus (HSV), has shown promising therapeutic effects in the treatment of advanced melanoma, both as a monotherapy or in combination with other immunotherapies, such as the immune checkpoint inhibitors (ICIs). With proven efficacy, T-VEC has been evaluated against a variety of other cancer types in a clinical trial setting. In this article, we will provide a review on OVs and the application of T-VEC in melanoma monotherapy and combination therapy. In addition, we will review the recent progress of T-VEC application in other cutaneous cancer types. Moreover, we will briefly describe our experience of T-VEC therapy at City of Hope, aiming to provide more insight for expanding its future application.

Single-agent Talimogene Laherparepvec (T-VEC) was developed for treatment of unresectable and injectable stage III-IV melanoma. Since its approval and reimbursement, studies have reported varying response rates. The purpose of this systematic review and meta-analysis was to investigate the efficacy and safety of T-VEC. Of 341 publications that were identified, eight studies with a total of 642 patients were included. In patients with stage IIIB-IVM1a, the pooled complete- and overall response rate (CRR and ORR) were 41% and 64%, respectively. In patients with stage IIIB-IVM1c, the pooled CRR and ORR were 30% and 44%, respectively. In patients with stage IVM1b and IVM1c, the pooled CRR and ORR were 4% and 9%, respectively. Adverse events (AEs) were seen in 41-100% of all patients and 0-11% of AEs were severe. In conclusion, single agent T-VEC achieves the highest response rates in patients with early metastatic melanoma and is well-tolerated with generally only mild toxicities.

Talimogene laherparepvec (T-VEC; IMLYGIC®, Amgen Inc.) is an oncolytic immunotherapy approved in Europe for the treatment of unresectable metastatic melanoma (stage IIIB-IVM1a). This study characterised real-world use of T-VEC in four European countries.
Data on demographics, treatment pattern, safety, and clinical effectiveness were examined in a retrospective chart review of patients with stage IIIB-IVM1a unresectable melanoma treated with T-VEC in surgical (the Netherlands) and medical (Austria, Germany, UK) oncology settings.
Overall, 66 patients were included (the Netherlands: n = 31; Austria, Germany, UK: n = 35). The median age was 69 years and 59.1% were female. At the time of T-VEC initiation, 47 patients (71.2%) had stage IIIB/C disease; of these, 30 were from the Netherlands. Although 72.7% patients overall received T-VEC as first-line therapy, this was higher in the Netherlands than the other countries (93.5% vs 54.3%). Of the 47 patients who discontinued T-VEC, 26 (55.3%) had no remaining injectable lesions (potentially indicating complete response); 20/26 of these patients were from the Netherlands. One patient discontinued T-VEC due to toxicity.
This study is the first comprehensive multinational evaluation of the use of T-VEC to treat unresectable stage IIIB/C-IVM1a melanoma in real-world clinical practice in Europe. The differences between European countries were apparent, with physicians in the Netherlands using T-VEC in patients with earlier advanced disease stage and in the first-line setting compared with other countries.

This study aimed to conduct a systematic review of preclinical and clinical evidence to chart the successful trajectory of talimogene laherparepvec (T-VEC) from the bench to the clinic.
This study was a systematic review. The primary outcome of interest was the efficacy of treatment, determined by complete response. Abstract and full-text selection as well as data extraction were done by two independent reviewers. The Cochrane risk of bias tool was used to assess the risk of bias in studies.
Embase, Embase Classic and OvidMedline were searched from inception until May 2016 to assess its development trajectory to approval in 2015.
Preclinical and clinical controlled comparison studies, as well as observational studies.
T-VEC for the treatment of any malignancy.
8852 records were screened and five preclinical (n=150 animals) and seven clinical studies (n=589 patients) were included. We saw large decreases in T-VEC\'s efficacy as studies moved from the laboratory to patients, and as studies became more methodologically rigorous. Preclinical studies reported complete regression rates up to 100% for injected tumours and 80% for contralateral tumours, while the highest degree of efficacy seen in the clinical setting was a 24% complete response rate, with one study experiencing a complete response rate of 0%. We were unable to reliably assess safety due to the lack of reporting, as well as the heterogeneity seen in adverse event definitions. All preclinical studies had high or unclear risk of bias, and all clinical studies were at a high risk of bias in at least one domain.
Our findings illustrate that even successful biotherapeutics may not demonstrate a clear translational road map. This emphasises the need to consider increasing rigour and transparency along the translational pathway.
CRD42016043541.