PD-1/PD-L1-IN-NP19, a PD-1/PD-L1 inhibitor, exhibits an IC50 of 12.5 nM against the human PD-1/PD-L1 interaction, potentially activating the tumor immune microenvironment and contributing to its antitumor effects[1].

PD-1/PD-L1-IN-NP19 (compound NP19) (0.37-10 μM; 72 h) significantly elevates the production of IFN-γ in a dose dependent manner from T cells co-cultured with tumor cells[1].PD-1/PD-L1-IN-NP19 exhibits much lower activity for inhibiting mouse PD-1/PD-L1 interaction with an IC50 in the micromolar range (>1μM), as compared to the inhibition of human PD1/PD-L1 interaction (IC50=12.5 nM)[1].PD-1/PD-L1-IN-NP19 (10 μM; 48 h) displays no apparent cytotoxic effects on A549, MCF-7, and B16-F10 cells at a concentration of 10 μM[1].

PD-1/PD-L1-IN-NP19 (compound NP19) (25-100 mg/kg; intragastric gavage once daily for 15 d) inhibits the growth of melanoma tumors dramatically in mice[1].PD-1/PD-L1-IN-NP19 (25 mg/kg; i.p. daily for 14 d) demonstrates significant antitumor efficacy with a tumor growth inhibition (TGI) of 76.5% and is well tolerated in an H22 hepatoma mouse model[1].PD-1/PD-L1-IN-NP19 (1 mg/kg; i.v.) shows the half time (t1/2=1.5±0.5 h), clearance rate (CL=0.9±0.2 L/h/kg) and apparent distribution volume (Vss=2.1±0.5 L/kg) in rats[1].PD-1/PD-L1-IN-NP19 (10 mg/kg; p.o.) shows the oral absorption (Tmax=0.6±0.2 h), long half-life (t1/2=10.9±7.7 h) and oral bioavailability (F=5%) in rats[1].