T-VEC, a genetically engineered herpes virus, has proven to be effective immunotherapy for patients with melanoma in a Phase 3 clinical trial.
Each year, there are more new cases of skin cancer than all other cancers combined. Luckily, the most prevalent types, basal and squamous cell carcinomas, are relatively benign. Melanoma, on the other hand, accounts for less than two percent of skin cancer cases, but the vast majority of deaths. Despite all the advances in the field, most patients do not respond to treatment. As the number of new cases of melanoma steadily increases, the development of new treatments that slow the progression of the disease becomes critical.
Recently, researchers reported that Talimogene laherparepvec (T-VEC) achieves a durable response in melanoma patients, with nearly 11% of patients experiencing a complete response, which is very significant for melanoma studies . T-VEC was engineered from herpes simplex virus type 1 (HSV-1) and designed to selectively replicate in and lyse tumor cells. Although it invades healthy cells, it is unable to replicate there, and they remain unharmed. In addition, T-VEC promotes local secretion of granulocyte macrophage colony-stimulating factor (GM-CSF) to recruit and activate antigen-presenting cells for subsequent induction of tumor-specific T-cell responses. Thus, T-VEC can directly kill cancer cells but also triggers systemic antitumor immune responses.
This immunotherapy study involved 436 patients with stage III or IV melanoma lesions that had been previously evaluated to be impossible to surgically remove. They were randomly assigned in a 2:1 ratio to receive intralesional T-VEC or subcutaneous GM-CSF. The researchers found that the durable response rate was significantly higher in T-VEC treated patients compared to the GM-CSF group. Additionally, both overall response rate and median overall survival were also higher in the T-VEC group. The greatest responses were seen in patients with less advanced disease and those who had yet to receive treatment. Lastly, T-VEC had few adverse effects, which included chills, nausea, flu-like symptoms, fatigue, and injection-site pain.
The results of this clinical trial demonstrate the potential benefits of T-VEC as a first-line, oncolytic immunotherapy for patients with metastatic melanoma that cannot be surgically removed. Ongoing studies are evaluating whether it can also halt the progression of more aggressive melanomas and advanced disease.
HemaCare provides a wide array of cancer disease-state blood products and primary cells for research purposes.
1 Andtbacka, R. H. et al. Talimogene Laherparepvec Improves Durable Response Rate in Patients With Advanced Melanoma. Journal of clinical oncology : official journal of the American Society of Clinical Oncology, doi:10.1200/jco.2014.58.3377 (2015).