ADME Proteomics Solutions for Navigating CYP2C Induction Challenges

Understanding drug-drug interactions (DDIs) is essential for ensuring patient safety, maintaining therapeutic efficacy, and providing critical prescribing information to clinicians. A significant component of DDI testing involves assessing a drug’s potential to interact with and/or induce the expression and activity of key drug metabolizing enzymes.

Regulatory agencies, including those aligned with ICH M12 guidelines, emphasize the evaluation of CYP enzyme induction for potential DDIs. While CYP1A2, CYP2B6, and CYP3A4 induction are part of the standard evaluation, the CYP2C family (CYP2C8, CYP2C9, and CYP2C19) require attention when CYP3A4 induction is observed.

These enzymes play an essential role in drug metabolism, and changes in their expression and activity can dramatically alter the safety and efficacy of co-administered drugs. Yet historically, CYP2C induction has been harder to evaluate in in vitro CYP induction assays compared to other families like CYP3A4 or CYP1A2.

A recent scientific poster from Eurofins Discovery highlights an important advancement in this space: an in vitro mRNA-based induction assay designed specifically to measure CYP2C8, 2C9, and 2C19 expression in primary human hepatocytes (PHH). The work expands on validated methods already used for CYP1A2, CYP2B6, and CYP3A4 and shows promising results for incorporating CYP2C assessment earlier in the discovery process.

Why This Matters for Discovery Teams

Because the CYP2C family metabolizes clinically important drugs – from anticoagulants to NSAIDs – even small induction effects can have significant downstream consequences.

ADME proteomics offers new solutions for navigating CYP2C induction challenges and can help teams:

• Generate more complete CYP induction data in support of regulatory guidance, including those outlined in the ICH M12 guideline, which recommends evaluating CYP2C induction when CYP3A4 induction is observed
• Make informed decisions about follow-up assays or mechanistic studies
• Prioritize compounds based on DDI profiles

What the Study Found

Eurofins Discovery evaluated 15 known compounds using PHH from multiple donors, measuring CYP2C8, CYP2C9, and CYP2C19 expression levels after 72 hours of treatment. The results showed:

• CYP2C8 and CYP2C9 induction aligned well with known in vivo inducers. For example, phenobarbital produced 2.8–8.0× induction for CYP2C8 and 3.1–4.7× for CYP2C9 across donors.
• Several other PXR-activators – rifampicin, carbamazepine, efavirenz, and others -also induced CYP2C8 and CYP2C9 in at least one donor.
• CYP2C19 induction, however, proved more variable, with only a single donor showing responsiveness to phenobarbital or rifampicin. This suggests that CYP2C19 may require alternative in vitro approaches or enhanced assay design.

Notably, the team also confirmed protein-level changes using Tandem Mass Tag (TMT^®) LC-MS/MS proteomics, strengthening the biological confidence in the findings and demonstrating how proteomics can complement mRNA readouts, especially for challenging endpoints like CYP2C19.

Why Awareness Starts Here

For many drug discovery teams, CYP induction isn’t top of mind until later in development but waiting can lead to challenges in satisfying regulatory guidance for DDI testing. By integrating CYP2C enzyme induction awareness earlier, organizations can:

• Reduce surprises in regulatory submissions
• Prevent avoidable attrition
• Ensure more robust data packages for future clinical phases
• Enhance confidence in compound selection and prioritization

Even if your program isn’t yet at the stage of full DDI evaluation, understanding how your compound interacts with CYP2C enzymes adds clarity and foresight that can shape smarter decision-making.

Where This Leads Next

As tools like mRNA induction assays and proteomics workflows become more accessible, teams can gain earlier and more precise insights into metabolic liabilities. Eurofins Discovery’s work highlights that mRNA-based approaches can reliably assess CYP2C8 and CYP2C9 induction, and that alternative strategies may be needed for CYP2C19.

For teams exploring how to modernize their DDI strategy or build awareness of potential metabolic risks, this is a strong example of how early, human-relevant in vitro systems can reduce uncertainty and help teams make better informed decisions.