Media Releases

U of T researchers lead study to determine individualized smoking cessation treatments

September 7, 2010

TORONTO, ON — Quit­ting smok­ing is hard, and researchers at the Uni­ver­si­ty of Toron­to and the Cen­tre for Addic­tion and Men­tal Health (CAMH) have dis­cov­ered one rea­son why: it’s in the genes.

Each smok­er has a dif­fer­ent genet­ic make­up, which influ­ences their response to dif­fer­ent treat­ments to help them quit. Now, these researchers plan to deter­mine how to best per­son­al­ize treat­ments to max­i­mize the effec­tive­ness of smok­ing ces­sa­tion efforts.

Mil­lions of adults in North Amer­i­ca try to quit smok­ing every year, but the suc­cess rates of smok­ing ces­sa­tion treat­ments vary wide­ly. And there are no per­son­al­ized approach­es to help­ing smok­ers quit that have been trans­lat­ed into clin­i­cal prac­tice.

The inter­na­tion­al study, led by Prof. Rachel Tyn­dale at U of T and CAMH and Prof. Caryn Ler­man at the Uni­ver­si­ty of Penn­syl­va­nia, will inves­ti­gate the phar­ma­co­ge­net­ics of nico­tine addic­tion treat­ment. It is backed by a $12-mil­lion (U.S.) grant through the Nation­al Insti­tute of Health’s Phar­ma­coge­nomics Research Net­work (PGRN) ini­tia­tive, a group of sci­en­tists from across North Amer­i­ca focused on under­stand­ing how genes affect a person’s response to med­i­cines.

Pre­vi­ous research led by Prof. Tyn­dale iden­ti­fied a genet­i­cal­ly informed mark­er that reflects indi­vid­ual dif­fer­ences in how quick­ly nico­tine breaks down in the body. This bio­mark­er can be used to pre­dict the suc­cess of dif­fer­ent smok­ing ces­sa­tion treat­ments for indi­vid­ual smok­ers. The new study will deter­mine how to trans­late this bio­mark­er into clin­i­cal prac­tice.

“This mark­er has the poten­tial to help clin­i­cians choose the best med­ica­tion for peo­ple try­ing to quit, based on their genet­ics, and thus improve ces­sa­tion response,” says Tyn­dale, a pro­fes­sor of Phar­ma­col­o­gy at U of T, and Cana­da Research Chair in Phar­ma­co­ge­net­ics and head of Phar­ma­co­ge­net­ics for CAMH. “This is the first prospec­tive ran­dom­ized tri­al using a genet­i­cal­ly informed bio­mark­er to opti­mize smok­ing treat­ment on an indi­vid­ual lev­el.”

The bio­mark­er, referred to as the nico­tine metabo­lite ratio (NMR), reflects genet­ic vari­a­tion in the CYP2A6 gene, as well as envi­ron­men­tal influ­ences on nico­tine metab­o­lism. In this study, 1350 adult smok­ers will have their NMR assessed to deter­mine whether they metab­o­lize nico­tine slow­ly or quick­ly. They will then be sort­ed into two groups – slow metab­o­liz­ers and nor­mal metab­o­liz­ers – and ran­dom­ized to treat­ment with either place­bo, a nico­tine patch, or Pfizer’s Chan­tix (vareni­cline). Each par­tic­i­pant will also pro­vide genet­ic mate­r­i­al (DNA) which will be used to iden­ti­fy addi­tion­al gene vari­ants that may also con­tribute to the nico­tine addic­tion treat­ment response. The prospec­tive, dou­ble-blind place­bo con­trolled tri­al will be com­plet­ed with­in the next four years.

Prof. Tyn­dale is the vice-chair of the PGRN. The PGRN ini­tia­tive is fund­ed by nine com­po­nents of the U.S. Nation­al Insti­tutes of Health: Nation­al Insti­tute of Gen­er­al Med­ical Sci­ences; the Nation­al Heart, Lung, and Blood Insti­tute; the Nation­al Can­cer Insti­tute; the Nation­al Insti­tute on Drug Abuse; the Eunice Kennedy Shriv­er Nation­al Insti­tute of Child Health and Human Devel­op­ment; the Nation­al Human Genome Research Insti­tute; the Nation­al Insti­tute of Men­tal Health; the Nation­al Insti­tute of Arthri­tis and Mus­cu­loskele­tal and Skin Dis­eases; and the Office of Research on Women’s Health in the Office of the Direc­tor.


For more infor­ma­tion, please con­tact:

Chris Gar­butt
Senior Com­mu­ni­ca­tions Offi­cer
Temer­ty Temer­ty Fac­ul­ty of Med­i­cine, Uni­ver­si­ty of Toron­to