IMMH-010 is an ester prodrug of YPD-29B, a potent programmed cell death ligand 1 (PD-L1) inhibitor. The metabolism of IMMH-010 was investigated and compared in various species. Four metabolites of IMMH-010 were identified, and the major metabolite was the parent compound, YPD-29B, which was mainly catalyzed by carboxylesterase 1 (CES1). We observed IMMH-010 metabolism in the plasma of various species. IMMH-010 was rapidly metabolized to YPD-29B in rat and mouse plasma, whereas it remained stable in human and monkey plasma. In the liver S9 fractions of human, monkey, dog, and rat, IMMH-010 was quickly transformed to YPD-29B with no obvious differences among species. In addition, the transformation ratio of IMMH-010 to YPD-29B was low in rat and human intestines, which indicated that the intestine was not an important site for IMMH-010 hydrolysis. Moreover, we demonstrated the remarkable antitumor efficacy of IMMH-010 in B16F10 melanoma and MC38 colon carcinoma xenograft mouse models. We also compared the pharmacokinetic profiles of IMMH-010 in rodents and primates. After oral administration of IMMH-010, the general exposure of active metabolite YPD-29B was slightly lower in primates than in rodents, suggesting that data should be extrapolated cautiously from rodents to humans.

The present study was performed to investigate the effect of bicyclol, a synthetic anti-hepatitis drug with anti-oxidative and anti-inflammatory properties, on anti-tuberculosis (anti-TB) drug-induced liver injury and related mechanisms in rats. Bicyclol was given to rats by gavage 2 h before the oral administration of an anti-TB drug once a day for 30 days. Liver injury was evaluated by biochemical and histopathological examinations. Lipid peroxidation, mitochondrial function, and the activity of antioxidants were measured by spectrophotometric methods. Cytokines expression and CYP2E1 activity were determined by ELISA assay and liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis. The expressions of hepatic CYP2E1 and hepatocyte growth factor (HGF) were assessed by Western blotting. As a result, bicyclol significantly protected against anti-TB drug-induced liver injury by reducing the elevated serum aminotransferases levels and accumulation of hepatic lipids. Meanwhile, the histopathological changes were also attenuated in rats. The protective effect of bicyclol on anti-TB drug-induced hepatotoxicity was mainly due to its ability to attenuate oxidative stress, suppress the inflammatory cytokines and CYP2E1 expression, up-regulate the expression of HGF, and improve mitochondrial function. Furthermore, administration of bicyclol had no significant effect on the plasma pharmacokinetics of the anti-TB drug in rats.

Indoleamine 2,3-dioxygenase (IDO) 1 is the key enzyme for regulating tryptophan metabolism and is an important target for interrupting tumor immune escape. In this study, we designed four series of compounds as potential IDO1 inhibitors by attaching various fragments or ligands to indole or phenylimidazole scaffolds to improve binding to IDO1. The compounds were synthesized and their inhibitory activities against IDO1 and tryptophan 2,3-dioxygenase were evaluated. The cytotoxicities of the compounds against two tumor cell lines were also determined. Two compounds with a phenylimidazole scaffold (DX-03-12 and DX-03-13) showed potent IDO1 inhibition with IC₅₀ values of 0.3–0.5 μM. These two IDO1 inhibitors showed low cell cytotoxicity, which indicated that they may exert their anti-tumor effect via immune modulation. Compound DX-03-12 was investigated further by determining the in vivo pharmacokinetic profile and anti-tumor efficacy. The pharmacokinetic study revealed that DX-03-12 had satisfactory properties in mice, with rapid absorption, moderate plasma clearance (∼36% of hepatic blood flow), acceptable half-life (∼4.6 h), and high oral bioavailability (∼96%). Daily oral administration of 60 mg/kg of compound DX-03-12 decreased tumor growth by 72.2% after 19 days in a mouse melanoma cell B16-F10 xenograft model compared with the untreated control. Moreover, there was no obvious weight loss in DX-03-12-treated mice. In conclusion, compound DX-03-12 is a potent lead compound for developing IDO1 inhibitors and anti-tumor agents.