First-in-human safety, tolerability, and pharmacokinetics of ammoxetine in healthy subjects: a randomized, double-blind, placebo-controlled phase I study

Validating the accuracy of mathematical model-based pharmacogenomics dose prediction with real-world data

OBJECTIVE

The study aims to verify the usage of mathematical modeling in predicting patients' medication doses in association with their genotypes versus real-world data.

METHODS

The work relied on collecting, extracting, and using real-world data on dosing and patients' genotypes. Drug metabolizing enzymes, i.e., cytochrome CYP 450, were the focus. A total number of 1914 subjects from 26 studies were considered, and CYP2D6 and CYP2C19 gene polymorphisms were used for the verification.

RESULTS

Results show that the mathematical model was able to predict the reported optimal dosing of the values provided in the considered studies. Predicting patients' optimal doses circumvents trial and error in patients' treatments.

DISCUSSION

The authors discussed the advantages of using a mathematical model in patients' dosing and identified multiple issues that would hinder the usability of raw data in the future, especially in the era of artificial intelligence (AI). The authors recommend that researchers and healthcare professionals use simple descriptive metabolic activity terms for patients and use allele activity scores for drug dosing rather than phenotype/genotype classifications.

CONCLUSION

The authors verified that a mathematical model could assist in providing data for better-informed decision-making in clinical settings and drug research and development.

In vitro, in vivo, and in silico approaches for evaluating the preclinical DMPK profiles of ammoxetine, a novel chiral serotonin and norepinephrine reuptake inhibitor

Background and Aim

Ammoxetine, a novel chiral serotonin and norepinephrine reuptake inhibitor, holds promise for major depressive disorder treatment. This study aimed to thoroughly investigate its preclinical drug metabolism and pharmacokinetics (DMPK) profiles.

Methods

The preclinical DMPK profiles of ammoxetine were examined through in vitro, in vivo, and in silico methods.

Results

Assessment of blood-brain barrier penetration via MDCK-MDR1 cells revealed strong brain permeation by ammoxetine, despite being a probable P-glycoprotein (P-gp) substrate. Molecular docking indicated a robust binding interaction between ammoxetine and P-gp. Ammoxetine was well absorbed orally, with Tmax ranging from 0.75 to 3.83 h in rats and 0.75-1.40 h in beagle dogs. At a 2 mg/kg dose in beagle dogs, ammoxetine exhibited an absolute bioavailability of approximately 42%. Plasma protein binding rates were around 50%-60% in beagle dogs, rats, and humans, suggesting moderate binding. Tissue distribution studies displayed rapid and extensive ammoxetine spread in major rat tissues post-gavage, with notable brain exposure and no tissue accumulation. Cumulative excretion rates in rats' urine, feces, and bile accounted for only 1.11% of the total administered drug, indicating extensive transformation into metabolites. Chiral inversion of ammoxetine was absent in vivo. Metabolic stability varied across species using liver microsomes, but beagle dogs showed clearance rates more akin to humans. Metabolic pathways unveiled two key metabolites, M1 and M2. M1, likely generated through methylenedioxyphenyl ring oxidation, involves CYP2C19 and CYP3A4, crucial human cytochrome P450 (CYP) enzymes for liver metabolism, while M2 is M1's glucuronide conjugate. Ammoxetine may exhibit saturation elimination trends with increasing doses in rats and beagle dogs. A high-throughput assay using the cocktail-substrate method indicated weak CYP inhibition by ammoxetine on CYP2D6 and CYP1A2, with minimal effects on other CYP enzymes, suggesting a low likelihood of CYP inhibition-related drug-drug interactions.

Conclusion

This study presents encouraging DMPK profiles of ammoxetine, backing its potential as a candidate compound for future clinical assessments.

Role of microglia in diabetic neuropathic pain

Approximately one-third of the patients with diabetes worldwide suffer from neuropathic pain, mainly categorized by spontaneous and stimulus-induced pain. Microglia are a class of immune effector cells residing in the central nervous system and play a pivotal role in diabetic neuropathic pain (DNP). Microglia specifically respond to hyperglycemia along with inflammatory cytokines and adenosine triphosphate produced during hyperglycemic damage to nerve fibers. Because of the presence of multiple receptors on the microglial surface, microglia are dynamically and highly responsive to their immediate environment. Following peripheral sensitization caused by hyperglycemia, microglia are affected by the cascade of inflammatory factors and other substances and respond accordingly, resulting in a change in their functional state for DNP pathogenesis. Inhibition of receptors such as P2X reporters, reducing cytokine expression levels in the microglial reactivity mechanisms, and inhibiting their intracellular signaling pathways can effectively alleviate DNP. A variety of drugs attenuate DNP by inhibiting the aforementioned processes induced by microglial reactivity. In this review, we summarize the pathological mechanisms by which microglia promote and maintain DNP, the drugs and therapeutic techniques available, and the latest advances in this field.

Review of the Chinese Landscape in Phase I Clinical Trials for Noncancer Innovative Drugs Over 2015 to 2020

In recent years, the research and development (R&D) of innovative drugs in China has been dramatically accelerated. And the early clinical study is crucial for drug R&D. However, little is known involving the change of phase I trials for noncancer drugs. We retrieved the data of phase I clinical trials for noncancer innovative drugs on the Registration and Information Disclosure Platform for Drug Clinical Studies on the Center for Drug Evaluation. The number of clinical trials proliferating in recent years and the average annual growth rates of chemical and biological drugs were 55.5% and 42.1%, respectively. Most trials were distributed in Beijing, Shanghai, and other developed coastal cities. Moreover, the clinical trials of innovative drugs in China were focused on the digestive and endocrine systems, whereas the pediatric and orphan drugs were scarce. Based on the data assessment, this work provided comprehensive analysis and suggestions about Chinese drug R&D. Significant advancement has been made in mainland China with the implementation of available policies and the emergence of advanced technologies. Though shortcomings, including uneven geographic distribution and lack of pediatric and orphan drugs, still exist, we believe progress will continue to be made in mainland China.