NP-12 inhibits spontaneous hematogenous spread in the B16F10 melanoma model Because NP-12 was effective in rescuing T cells from both PD-L1 and PD-L2, we tested the efficacy of NP-12 in B16F10 mouse melanoma spontaneous lung metastasis model. B16F10 cells were injected intravenously on day 0 and dosed with NP-12 starting from day 1. The animals were administered with NP12 subcutaneously at 3 mg/kg/day dose for a period of 14 days. Treatment with NP-12 resulted in a 66% reduction in metastatic nodules as compared with a vehicle control (Fig. 5A)