Allelic expression of phase II metabolizing enzymes and relationship to irinotecan toxicity

Area of Science:

• Pharmacogenomics
• Genetics
• Drug Metabolism

Background:

• Adverse drug responses affect approximately 15% of approved drugs, leading to variable patient outcomes.
• Genetic variations, particularly single nucleotide polymorphisms (SNPs), in genes encoding drug targets, metabolizing enzymes, or transporters often explain these variable responses and toxicity risks.
• Pharmacogenomics, encompassing the study of interactions within the entire gene complement, provides a framework for understanding these genetic influences on drug efficacy and safety.

Purpose of the Study:

• To investigate the influence of single nucleotide polymorphisms (SNPs) in phase II metabolizing enzymes on irinotecan-induced toxicity.
• To highlight the role of pharmacogenomics in predicting and managing adverse drug reactions.

Main Methods:

• Review of literature on pharmacogenomics and drug metabolism.
• Analysis of the impact of SNPs in genes encoding phase II metabolizing enzymes.
• Focus on irinotecan as a case study for drug-induced toxicity.

Main Results:

• SNPs in phase II metabolizing enzymes can significantly alter drug disposition and metabolic pathways.
• These genetic variations can lead to increased or decreased drug efficacy and heightened risk of toxicity.
• Specific SNPs in phase II enzymes are implicated in the variable toxicity profiles observed with irinotecan treatment.

Conclusions:

• Genetic variations, specifically SNPs in phase II metabolizing enzymes, play a crucial role in irinotecan-induced toxicity.
• Pharmacogenomic approaches are essential for personalizing drug therapy and minimizing adverse events.
• Understanding these genetic factors can guide clinical decision-making for improved patient safety and treatment effectiveness.