Institutional members access full text with Ovid®

Share this article on:

The κ-opioid receptor gene as a predictor of response in a cocaine vaccine clinical trial

Nielsen, David A.a,b; Hamon, Sara C.c; Kosten, Thomas R.a,b

doi: 10.1097/YPG.0000000000000008
Original Articles

Objectives We examined the pharmacogenetic association between a variant in the κ-opioid receptor (OPRK1) gene and the response to treatment with a cocaine vaccine tested in a recent clinical trial (October 2003 to April 2005). This gene has a protective allele for opioid addiction that may act by the inhibiting dopamine activation associated with reinforcement.

Methods Sixty-nine DNA samples were obtained from 114 cocaine-dependent and opioid-dependent patients who were enrolled in a 16-week phase IIb randomized double-blind placebo-controlled trial and received five vaccinations over the first 12 weeks. We genotyped 66 of these patients for the rs6473797 variant of the OPRK1 gene and compared vaccine patients with placebo patients in terms of cocaine-free urines over time.

Results Using repeated measures analysis of variance corrected for population structure, it was seen that vaccine pharmacotherapy reduced cocaine-positive urines significantly on the basis of the OPRK1 genotype. Among patients treated with the cocaine vaccine, those who were homozygous for the protective A allele of rs6473797 had the proportion of positive urines drop from 78 to 51% on using the vaccine (point-wise P<0.0001, experiment-wise P<0.005), whereas the positive urines of individuals carrying the nonprotective, risk G allele dropped from 82 to 77%. Strong treatment by single nucleotide polymorphism interactions reflected a lower baseline and significant reduction for placebo patients with the risk G allele (P<0.00001).

Conclusion This study indicates that a patient’s OPRK1 genotype could be used to identify a subset of individuals for whom vaccine treatment may be an effective pharmacotherapy for cocaine dependence.

aMenninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine

bMichael E. DeBakey V.A. Medical Center (MEDVAMC), Houston, Texas

cLaboratory of Statistical Genetics, The Rockefeller University, New York, New York, USA

Trial Registration: Protocol ID: NIDA-15477-1

Clinical ID: NCT00142857

Correspondence to David A. Nielsen, PhD, MEDVAMC, 2002 Holcombe Blvd., Research 151, Bldg 110, Rm 227, Houston, TX 77030, USA Tel: +1 713 791 1414 x6289; fax: +1 713 794 7240; e-mail:

Received December 14, 2012

Accepted April 7, 2013

© 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins