Preclinical pharmacokinetic studies and prediction of human PK profiles for Deg-AZM, a clinical-stage new transgelin agonist.

Introduction: Deglycosylated azithromycin (Deg-AZM), a newly developed Class I drug with good therapeutic effects on slow transit constipation, is a small-molecule transgelin agonist that has been approved for clinical trials in 2024. The preclinical pharmacokinetic profile of Deg-AZM was investigated to support further development. Methods: A LC-MS/MS method was established and validated to detected the concentration of Deg-AZM in various biological samples. In vivo tests such as pharmacokinetic studies in rats and dogs, tissue distribution studies in rats, and extraction studies in rats were conducted to investigated the preclinical pharmacokinetic behaviors of Deg-AZM comprehensively. The plasma protein rate of Deg-AZM was determined by rapid equilibrium dialysis method in vitro. The metabolic stability and metabolite profile of Deg-AZM was assessed using pooled mice, rats, dogs, monkeys and humans microsomes in vitro. The PK profiles of Deg-AZM in human was predicted based on physiologically based pharmacokinetic (PBPK) models. Results: The plasma protein binding rates of Deg-AZM were lower in mice and rats, higher in dogs, and moderate in humans. The metabolic process of Deg-AZM was similar in rat and human liver microsomes. From Pharmacokinetic studies in rats and dogs, Deg-AZM was rapidly absorbed into the blood and then quickly eliminated. Plasma exposure of Deg-AZM was dose dependent with no accumulation after continuous gavage administration. In addition, there is no significant gender difference in the pharmacokinetic behavior of Deg-AZM. Deg-AZM was widely distributed in the tissues without obvious accumulation, and mainly excreted from the urinary excretion pathway. Furthermore, the pharmacokinetic profiles of Deg-AZM in humans showed dose dependency. Conclusion: The pharmacokinetic profiles of Deg-AZM was fully explored, these results could provide valuable information to support the first-in-human dosage prediction and phase I clinical design.

Lenacapavir: A Novel, Potent, and Selective First-in-Class Inhibitor of HIV-1 Capsid Function Exhibits Optimal Pharmacokinetic Properties for a Long-Acting Injectable Antiretroviral Agent.

Lenacapavir (LEN) is a picomolar first-in-class capsid inhibitor of human immunodeficiency virus type 1 (HIV-1) with a multistage mechanism of action and no known cross resistance to other existing antiretroviral (ARV) drug classes. LEN exhibits a low aqueous solubility and exceptionally low systemic clearance following intravenous (IV) administration in nonclinical species and humans. LEN formulated in an aqueous suspension or a PEG/water solution formulation showed sustained plasma exposure levels with no unintended rapid drug release following subcutaneous (SC) administration to rats and dogs. A high total fraction dose release was observed with both formulations. The long-acting pharmacokinetics (PK) were recapitulated in humans following SC administration of both formulations. The SC PK profiles displayed two-phase absorption kinetics in both animals and humans with an initial fast-release absorption phase, followed by a slow-release absorption phase. Noncompartmental and compartmental analyses informed the LEN systemic input rate from the SC depot and exit rate from the body. Modeling-enabled deconvolution of the input rates from two processes: absorption of the soluble fraction (minor) from a direct fast-release process leading to the early PK phase and absorption of the precipitated fraction (major) from an indirect slow-release process leading to the later PK phase. LEN SC PK showed flip-flop kinetics due to the input rate being substantially slower than the systemic exit rate. LEN input rates via the slow-release process in humans were slower than those in both rats and dogs. Overall, the combination of high potency, exceptional stability, and optimal release rate from the injection depot make LEN well suited for a parenteral long-acting formulation that can be administered once up to every 6 months in humans for the prevention and treatment of HIV-1.

Pharmacokinetics and metabolism of brexpiprazole, a novel serotonin-dopamine activity modulator and its main metabolite in rat, monkey and human.

The pharmacokinetics of brexpiprazole were investigated in the in vitro and in vivo.The total body clearance of brexpiprazole in rat and monkey was 2.32 and 0.326 L/h/kg, respectively, after intravenous administration, and oral availability was 13.6% and 31.0%, respectively. Dose-dependent exposures were observed at dose ranges between 1-30 mg/kg in the rat and 0.1-3 mg/kg in the monkey.Brexpiprazole distributed widely to body tissues, and Vd,z were 2.81 and 1.82 L/kg in rat and monkey, respectively. The serum protein binding of brexpiprazole was 99% or more in animals and human. Uniform distribution character among the species was suggested by a traditional animal scale-up method.A common main metabolite, DM-3411 was found in animals and humans in the metabolic reactions with the liver S9 fraction. CYP3A4 and CYP2D6 were predominantly involved in the metabolism.The affinity of DM-3411 for D2 receptors was lower than that of brexpiprazole, and neither DM-3411 nor any metabolites with affinity other than M3 were detected in the brain, demonstrating that brexpiprazole is only involved in the pharmacological effects.Overall, brexpiprazole has a simple pharmacokinetic profile with good metabolic stability, linear kinetics, and no remarkable species differences with regard to metabolism and tissue distribution.

Nonclinical pharmacokinetics and metabolism of EPZ-5676, a novel DOT1L histone methyltransferase inhibitor.

(2R,3R,4S,5R)-2-(6-Amino-9H-purin-9-yl)-5-((((1r,3S)-3-(2-(5-(tert-butyl)-1H-benzo[d]imidazol-2-yl)ethyl)cyclobutyl)(isopropyl)amino)methyl)tetrahydrofuran-3,4-diol (EPZ-5676) is a novel DOT1L histone methyltransferase inhibitor currently in clinical development for the treatment of MLL-rearranged leukemias. This report describes the preclinical pharmacokinetics and metabolism of EPZ-5676, an aminonucleoside analog with exquisite target potency and selectivity that has shown robust and durable tumor growth inhibition in preclinical models. The in vivo pharmacokinetics in mouse, rat and dog were characterized following i.v. and p.o. administration; EPZ-5676 had moderate to high clearance, low oral bioavailability with a steady-state volume of distribution 2-3 fold higher than total body water. EPZ-5676 showed biexponential kinetics following i.v. administration, giving rise to a terminal elimination half-life (t1/2 ) of 1.1, 3.7 and 13.6 h in mouse, rat and dog, respectively. The corresponding in vitro ADME parameters were also studied and utilized for in vitro-in vivo extrapolation purposes. There was good agreement between the microsomal clearance and the in vivo clearance implicating hepatic oxidative metabolism as the predominant elimination route in preclinical species. Furthermore, low renal clearance was observed in mouse, approximating to fu -corrected glomerular filtration rate (GFR) and thus passive glomerular filtration. The metabolic pathways across species were studied in liver microsomes in which EPZ-5676 was metabolized to three monohydroxylated metabolites (M1, M3 and M5), one N-dealkylated product (M4) as well as an N-oxide (M6).