Dr Preskorn Replies

See original letter by Berm et al and related article by Preskorn et al.

Dr Preskorn Replies

To the Editor: Thank you for the opportunity to respond and thank Dr Berm and colleagues for their thoughtful and thought-provoking letter. My comments are solely from my perspective and do not necessarily reflect the views of my coauthors or the study sponsor as time did not permit a response from the entire group. I am gratified by the interest this article1 has generated and believe it is reflective of the importance of the topic and the study results. I do not disagree with the points raised in Dr Berm and colleagues’ letter, which complements and extends points made in our article.

Pharmacogenomic information is rapidly expanding, and pharmacogenomic testing is increasingly being made available to clinicians.2 However, many of these clinicians were trained in an era before such knowledge was available. For me, that raises several questions:

1. The test results alone may not be sufficient. Instead, an educational component about how to interpret the results may also be needed especially given the extent and complexity of multiple medication use in clinical practice. Although that was not the primary thrust of our study, the results did clearly document that extent and complexity.
2. How well has the genetic information been vetted in terms of clinical applicability? What is the standard that is used to determine whether the genetic information is worthy of being used clinically? Is that standard published and uniform amongst the various companies offering such testing services? At a minimum, it would seem that the genetic finding should have been reproduced by multiple laboratories and the variance in response accounted for by the test of sufficient magnitude to be clinically meaningful.

I have had these concerns for some time, but they were reinforced by the letter from Dr. Berm and colleagues, and I wonder how many clinicians in general practice are comfortable with their mastery of the points raised in her letter.

The overarching issue to me is how to provide information on pharmacogenomics and molecular pharmacology to clinicians at the point of care with sufficient context so that the clinicians can optimally use it to make appropriate therapeutic decisions for their patients.

References

1. Preskorn SH, Kane CP, Lobello K, et al. Cytochrome P450 2D6 phenoconversion is common in patients being treated for depression: implications for personalized medicine. J Clin Psychiatry. 2013;74(6):614-621. PubMed doi:10.4088/JCP.12m07807

2. Preskorn SH, Hatt CR. How pharmacogenomics (PG) are changing practice: implications for prescribers, their patients, and the healthcare system (PG series part I). J Psychiatr Pract. 2013;19(2):142-149. PubMed doi:10.1097/01.pra.0000428559.01953.73

Sheldon H. Preskorn, MD

[email protected]

Author affiliation: Department of Psychiatry, Clinical Research Institute, Wichita, Kansas.

Potential conflicts of interest: Dr Preskorn has received grant/research support from or has served as a consultant, on the advisory board, or on the speakers bureau over the past 12 months for Abbott, Biovail, Boehringer-Ingelheim, Bristol-Myers Squibb, Cyberonics, Dey Pharma, Eisai, Eli Lilly, EnViVo, US Food and Drug Administration (FDA), Ipsen, Johnson & Johnson, Lundbeck, Merck, Naurex, National Institute of Mental Health, Orexigen, Otsuka, Pierre Fabre, Pfizer, Stanley Medical Research Institute, and Sunovion.

Funding/support: The study discussed in this letter was sponsored by Wyeth Research, which was acquired by Pfizer in October 2009.

J Clin Psychiatry 2013;74(10):1025-1026 (doi:10.4088/JCP.13lr08555a).

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