The efficacy and safety of varenicline for smoking cessation using a flexible dosing strategy in adult smokers: a randomized controlled trial.
OBJECTIVE
To determine whether self-regulated flexible dosing with varenicline tartrate is safe and effective for smoking cessation.


METHODS
320 healthy, motivated-to-quit smokers (> or =10 cigarettes/day) aged 18-65 years, entered a multicenter, randomized, double-blind, placebo-controlled study - conducted between December 26, 2001 and June 24, 2003 - with a 12-week treatment phase and 40-week, double-blind, non-treatment follow-up. Treatment consisted of varenicline or placebo in fixed doses (Week 1: titrated from 0.5 to 1.0 mg/day) followed by a self-regulated flexible schedule (Weeks 2-12: 0.5-2.0 mg/day).


METHODS
Primary outcomes included carbon monoxide-confirmed continuous abstinence rate (CAR) from smoking for Weeks 4 through 7, 9 through 12, and 9 through 52. Secondary outcomes included CAR from Weeks 9 through 24, 7-day point prevalence of abstinence, safety assessments, and measures of craving, withdrawal, and smoking reward.


RESULTS
Superior CARs were observed in varenicline-treated (n = 157) versus placebo participants (n=155) for Weeks 4 through 7 (38.2 vs. 11.6%), 9 through 12 (40.1 vs. 11.6%), 9 through 24 (28.0 vs. 9.0%), and 9 through 52 (22.3 vs. 7.7%) (all p<0.001). Seven-day point prevalence was higher in varenicline-treated than placebo participants at Weeks 12 (46.5 vs. 14.2%; p<0.001), 24 (32.5 vs. 13.5%; p<0.001), and 52 (28.0 vs. 13.5%; p=0.001). Overall, medication compliance was high, although varenicline-treated, but not placebo, participants tended to taper down their dosage over time. Total treatment-emergent AEs were 77.1% (varenicline: 121/157) and 65.8% (placebo: 102/155). Few AEs led to treatment discontinuation (varenicline: 11/157, 7.0% and placebo: 7/155, 4.5%). Participants were primarily healthy Caucasians, so more research is necessary to determine how applicable these findings are to other populations.


CONCLUSIONS
A self-regulated, flexible dosing regimen of varenicline is well tolerated, with superior effectiveness versus placebo for smoking cessation.
Brown University, Providence, RI, USA. Raymond_Niaura@brown.edu
Raymond
R
Niaura
J Taylor
JT
Hays
Douglas E
DE
Jorenby
Frank T
FT
Leone
John E
JE
Pappas
Karen R
KR
Reeves
Kathryn E
KE
Williams
Clare B
CB
Billing
D000293:Adolescent; D000328:Adult; D000368:Aged; D001552:Benzazepines / Q000008:administration & dosage* / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010919:Placebos; D011810:Quinoxalines / Q000008:administration & dosage* / Q000009:adverse effects; D012907:Smoking / Q000188:drug therapy*; D016540:Smoking Cessation; D016896:Treatment Outcome; D000068580:Varenicline
D001552:Benzazepines; D010919:Placebos; D011810:Quinoxalines; D000068580:Varenicline