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Genetic Variant in CHRNA5 and Response to Varenicline and Combination Nicotine Replacement in a Randomized Placebo‐Controlled Trial
Author(s) -
Chen LiShiun,
Baker Timothy B.,
Miller J. Philip,
Bray Michael,
Smock Nina,
Chen Jingling,
Stoneking Faith,
Culverhouse Robert C.,
Saccone Nancy L.,
Amos Christopher I.,
Carney Robert M.,
Jorenby Douglas E.,
Bierut Laura J.
Publication year - 2020
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt.1971
Subject(s) - varenicline , placebo , medicine , smoking cessation , nicotine replacement therapy , randomized controlled trial , nicotine , abstinence , genotype , psychiatry , genetics , biology , pathology , alternative medicine , gene
It is unclear if genetic variants affect smoking cessation treatment response. This study tested whether variants in the cholinergic receptor nicotinic alpha 5 subunit (CHRNA5) predict response to smoking cessation medication by directly comparing the two most effective smoking cessation pharmacotherapies. In this genotype-stratified randomized, double-blind, placebo-controlled clinical trial (May 2015-August 2019 in St Louis, Missouri), smokers were randomized by genotype in blocks of six (1:1:1 ratio) to three conditions: 12 weeks of placebo (n = 273), combination nicotine patch and lozenge (combination nicotine replacement therapy, cNRT, n = 275), or varenicline (n = 274). All participants received counseling and were followed for 12 months. The primary end point was biochemically verified 7-day point prevalence abstinence at the end of treatment (EOT, week 12). Trial registration and eligibility criteria are on clinicaltrials.gov (https://clinicaltrials.gov/) (NCT02351167). We conducted the genetic analyses separately for 516 European ancestry (EA) smokers and 306 non-EA smokers (including 270 African American smokers). In African American smokers, there was a genotype-by-treatment interaction for EOT abstinence (χ 2 = 10.7, degrees of freedom = 2. P = 0.0049): specifically, cNRT was more effective in smokers with rs16969968 GG genotype than was placebo, while varenicline was more effective in smokers of GA/AA genotypes. In EA ancestry smokers, there was no significant genotype-by-treatment interaction. In the whole sample, although both were effective at EOT, only varenicline, and not cNRT, was significantly effective relative to placebo at 6-month follow-up. Importantly, this study suggests that genetic information can further enhance smoking cessation treatment effectiveness.