CSF2 and melanoma: In representative the OPTiM study, which was a randomized, phase III open-label clinical trial to evaluate T-VEC monotherapy compared with GM-CSF in patients with unresectable stage IIIB-IV melanoma, the ORR of T-VEC was significantly higher than that of GM-CSF (26.4% vs. 5.7%; p < 0.001) [15].