PD-1/PD-L1-IN-9 is a potent and orally active inhibitor of PD-1/PD-L1 interaction, with an IC 50 of 3.8 nM. PD-1/PD-L1-IN-9 can enhance the killing activity of tumor cells by immune cells. PD-1/PD-L1-IN-9 also exhibits significant in vivo antitumor activity in a CT26 mouse model In Vitro PD-1/PD-L1-IN-9 (compound 24) (46.9-1500 nM; pretreated for 2 h) dose-dependently significantly activates the antitumor immunity of peripheral blood mononuclear cells (PBMCs) to MDB-MB 231 cells, with an EC 50 of ∼100 nM. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo PD-1/PD-L1-IN-9 (compound 24) (40-80 mg/kg; p.o.; once a day for 2 weeks) inhibits tumor growth in a dose-dependent manner and does not cause any body weight loss or mortality of mice . PD-1/PD-L1-IN-9 (3 mg/kg; i.v.; single dose) exhibits half-life (T 1/2 =4.2 h), plasma clearance (Cl=11.5 L/h/kg) and C max (1233 ng/mL) in rats . PD-1/PD-L1-IN-9 (25 mg/kg; p.o.; single dose) exhibits moderate oral bioavailability (F=22 %), half-life (t 1/2 =6.4 h) and C max (192 ng/mL) in rats . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Animal Model: Male BALB/c mice (5-6 weeks) were inoculated CT26 cells Dosage: 40 mg/kg, 80 mg/kg Administration: Oral gavage; once daily, for 2 weeks Result: Significantly decreased the final tumor weight, with TGI values of 60 and 67% at the dose of 40 and 80 mg/kg, respectively. Animal Model: Pharmacokinetic analysis in sprague-Dawley (SD) rats Dosage: 3 mg/kg and 25 mg/kg Administration: Intravenous injection or oral gavage; single dose Result: Route Dose (mg/kg) AUC (0-t) (ng·h/mL) C max (ng/mL) t 1/2 (h) T max Cl (L·h/kg) V z (L/kg) F (%) i.v. 3 430.5 1233 4.2 0.03 11.5 78.6 / p.o. 25 787.4 192 6.4 0.69 28.8 249.3 22 Form:Solid IC50& Target:IC50: 3.8 nM (PD-1/PD-L1)