Evaluating Xenobiotic Drug Metabolism and Transport

Tech Snapshot captures today’s cutting-edge tools and technologies that will help drive drug discovery tomorrow. This installment was written by SEKISUI XenoTech, whose mission is to improve the health and welfare of society and future generations by supporting sustainable development of life-saving therapies through science grounded in excellence and quality.

SEKISUI XenoTech’s patented technology for evaluating xenobiotic drug metabolizing enzymes is one of their most innovative services. This patented technique gives drug developers a tool to evaluate drug interaction potential of small molecule immune-modulator drugs. The assay determines whether an immuno modulator-stimulated release of cytokines can change expression of drug metabolizing enzymes in human hepatocytes. The affected change could cause a clinical drug-drug interaction (DDI) whereby the clearance of another drug is affected, potentially resulting in toxicity or reduced therapeutic effect.

This technique now can be applied to both small molecule drugs and large molecule biologics. Any drug developer with a compound that causes a cytokine release could use this assay to determine risk of a consequential drug-drug interaction, which could be detrimental to an otherwise solid program.

FDA Position: Nonclinical DDI Assessment of Biologics

In recent years, SEKISUI XenoTech has seen a shift in pharmaceutical development from small molecule therapeutics to large molecules, also known as biologics. This broad category of drugs includes monoclonal antibodies, hormones, growth factors, enzymes, vaccines, oligonucleotides and other large molecules.

Some biologic drugs have been shown to cause an inflammatory response, leading to elevated cytokine levels and subsequent cytokine-mediated suppression of drug-metabolizing enzymes such as Cytochrome P450s (CYPs). The FDA’s 2020 Final Guidance for Industry, “In Vitro Drug Interaction Studies – Cytochrome P450 Enzyme- and Transporter-Mediated Drug Interactions,” recognizes that some biologics need to be evaluated in vitro or in vivo for their potential to alter the disposition of small molecule drugs, particularly if the biologic itself is a cytokine or cytokine modulator.

To evaluate a biologic drug’s potential to cause a DDI with co-administered small molecule drugs, we offer a study comprising of two assays:

• Cytokine Release
• Hazard Identification

Cytokine Release Assay: Is your therapeutic protein a cytokine modulator?

It is important to recognize a test biologic’s cytokine modulation potential early in the process of drug development. To evaluate whether or not a biologic drug candidate is a cytokine modulator, we offer a Cytokine Release Assay. In this assay, whole blood is treated with the test biologic to examine whether it elicits an immune response. The cytokine response in the blood is then quantified in the isolated plasma and compared to an appropriate positive control.

Hazard Identification: Can your drug’s cytokine response lead to a drug-drug interaction?

For cytokine modulators, we offer a Hazard Identification Study to determine the potential and extent of direct- or cytokine-mediated effects of a test biologic on CYP enzymes.

• For evaluation of direct effect, co-cultures containing fresh human hepatocytes and Kupffer cells are treated with test biologic
• For evaluation of indirect, cytokine-mediated effect, co-cultures containing fresh human hepatocytes and Kupffer cells are treated with plasma that was isolated from whole blood treated with the test biologic in a specialized assay designed and patented by SEKISUI XenoTech’s Research & Development team
• Following treatment, CYP enzymatic activity is measured and change in enzyme expression levels is quantified by qRT-PCR analysis

Analysis of assay data allows a drug developer to determine the test biologic’s potential to cause cytokine release in vivo and then compare the magnitude of response of the drug candidate to known cytokine modulators currently in the clinic.