AAPS PharmSci

, Volume 2, Issue 4, pp 1–11 | Cite as

CYP2D6 Genotyping as an alternative to phenotyping for determination of metabolic status in a clinical trial setting

  • Suzin McElroy
  • Jodi Richmond
  • Maruja Lira
  • David Friedman
  • B. Michael Silber
  • Patrice M. Milos
  • Christoph Sachse
  • Jürgen Brockmöller
  • Ivar Roots


The emerging application of pharmacogenomics in the clinical trial setting requires careful comparison with more traditional phenotyping methodologies, particularly in the drug metabolism area where phenotyping is used extensively. The research objectives of this study were 1) to assess the utility of cytochrome P450 2D6 (CYP2D6) genotyping as an alternative to traditional phenotyping as a predictor of poor metabolizer status; 2) to identify issues for consideration when implementing CYP2D6 genotyping in clinical trials; and 3) to outline the advantages and disadvantages of CYP2D6 genotyping compared with phenotyping. DNA samples obtained from 558 previously phenotyped individuals were blindly genotyped at the CYP2D6 locus, and the genotype-phenotype correlation was then determined. The CYP2D6 genotyping methodology successfully predicted all but 1 of the 46 poor metabolizer subjects, and it was determined that this 1 individual had a novel (presumably inactive) mutation within the coding region. In addition, we identified 2 subjects with CYP2D6 genotypes indicative of poor metabolizers who had extensive metabolizer phenotypes as determined by dextromethorphan/dextrorphan ratios. This finding suggests that traditional phenotyping methods do not always offer 100% specificity. Our results suggest that CYP2D6 genotyping is a valid alternative to traditional phenotyping in a clinical trial setting, and in some cases may be better. We also discuss some of the issues and considerations related to the use of genotyping in clinical trials and medical practice.

Key Words

Cytochrome P450 2D6 Pharmacogenomics Drug Metabolism Genotyping 


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Copyright information

© American Association of Pharmaceutical Scientists 2000

Authors and Affiliations

  • Suzin McElroy
    • 1
  • Jodi Richmond
    • 1
  • Maruja Lira
    • 1
  • David Friedman
    • 1
  • B. Michael Silber
    • 1
  • Patrice M. Milos
    • 1
  • Christoph Sachse
    • 2
  • Jürgen Brockmöller
    • 2
  • Ivar Roots
    • 2
  1. 1.Pharmacogenomics and Clinical Biochemical Measurements, Discovery ResearchPfizer Global Research and DevelopmentGroton
  2. 2.Institute of Clinical Pharmacology, University Medical Centre ChariteHumboldt University of BerlinBerlinGermany

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