Based on the phase III OPTiM trial demonstrating an ORR of 31.5% with DRR 19% of T-VEC in patients with unresectable stage IIIB-IVM1c melanoma, superior to effects of subcutaneous GM-CSF, T-VEC remains the only oncolytic virus FDA-approved for use in melanoma [34]. This evidence concerns the gene CSF2 and melanoma.