ALG-093940的临床前特征研究：一种高效、口服生物利用度良好的小分子PD-1/PD-L1抑制剂，靶向PD-L1的二聚化、内化和降解

Background: PD-1/PD-L1 antibody-based therapies have demonstrated tremendous success in the treatment of a variety of cancers. However, these antibody drugs are associated with several disadvantages, such as weak tumor penetration, immune-related adverse events and emergence of anti-drug antibodies. Here, we report the characterization of ALG-093940, a potent and orally bioavailable small molecule PD-1/PD-L1 inhibitor that binds to PD-L1 and promotes PD-L1 dimerization, internalization and degradation, offering an alternate mechanism of action with potential advantages over PD-1/PD-L1 antibody therapeutics. Methods: The interaction of PD-1/PD-L1 and PD-L1 dimerization were assessed by AlphaLISA®. Inhibition of PD-1/PD-L1 in cell culture was measured using PD-1 expressing Jurkat NFAT luciferase T cells and CHO-hPD-L1 cells. In vivo PK/PD/Efficacy were assessed in a humanized-PD-L1 MC38 subcutaneous tumor mouse model. In vitro ADME tox profile used standard assays. Pharmacokinetic (PK) studies were performed in mice, rat, dog, and cynomolgus monkeys. Safety and tolerability were evaluated by oral administration in rats and cynomolgus monkeys. Results: ALG-093940 inhibited PD-1/PD-L1 interaction with an IC 50 of 0.048 nM and induced PD-L1 dimerization with an EC 50 of 79 nM. ALG-093940 showed comparable T-cell activation potency to INCB086550 an orally dosed small molecule PD-L1 inhibitor which demonstrated clinical responses in a phase I study. Furthermore, treatment of CHO-hPD-L1 cells with ALG-093940 resulted in internalization and reduction of PD-L1 protein levels. In ex vivo human PBMC assays, ALG-093940 demonstrated PD-L1 target engagement, T cell activation and immune cell mediated tumor cell killing. In the in vivo humanized-PD-L1 MC38 mouse model, oral once daily dosing of ALG-093940 at 1.5, 15, 50 or 150 mg/kg demonstrated dose-dependent PD-L1 target engagement and tumor growth inhibition, where tumor size correlated with tumor-infiltration of CD8 + T-cells. ALG-093940 demonstrated no in vitro liabilities for CYP-mediated drug-drug interactions, off target toxicity, cardiovascular safety, or genotoxicity. Preclinical in vivo PK data suggests once-daily oral dosing is feasible in humans. In addition, ALG-093940 was well tolerated when orally administered in rats for 14 days up the highest dose tested at 150 m/kg/day (up to the saturation of exposure), and in cynomolgus monkeys as a single dose up to 500 mg/kg and multiple doses for 3 days at 300 mg/kg/day. Conclusions: ALG-093940, an orally available small molecule, is a potent PD-1/PD-L1 inhibitor targeting PD-L1 dimerization, internalization and degradation. ALG-093940 demonstrated excellent efficacy and safety, warranting further evaluation as a potential clinical candidate for the treatment of cancer.