Reactive metabolites in early drug development: predictive in vitro tools

Area of Science:

• Drug metabolism and toxicology
• Biomarker discovery
• Chemical reactivity assessment

Background:

• Drug metabolism can generate reactive metabolites, a major cause of toxicity and drug development attrition.
• Early detection of reactive metabolite formation is critical for safe drug development and clinical use.

Purpose of the Study:

• To review a multi-year project and literature on in vitro tests for detecting reactive metabolites.
• To delineate prerequisites for effective reactive metabolite detection assays.

Main Methods:

• Examination of small- and large-molecular trapping agents (e.g., glutathione, peptides, DNA).
• Utilizing mass spectrometry for adduct detection.
• Incorporating cellular toxicity biomarkers (e.g., Nrf2 pathway).

Main Results:

• Small-molecule trapping agents show high sensitivity but can yield false positives.
• Peptide and DNA trapping results align with small-molecule trappers but have distinct findings.
• Interpreting in vitro adduct data requires integration with cellular toxicity biomarker information.

Conclusions:

• Current in vitro tools can characterize chemical liability and correlate with toxicity.
• Significant gaps remain in understanding the mechanistic link between reactive metabolites and adverse effects.
• Further research is needed to fully elucidate the mechanisms connecting reactive metabolites to toxicity.