NTS-105 decreased cell death and preserved long-term potentiation in an in vitro model of moderate traumatic brain injury.

Traumatic brain injury (TBI) is a major cause of hospitalization and death. To mitigate these human costs, the search for effective drugs to treat TBI continues. In the current study, we evaluated the efficacy of the novel neurosteroid, NTS-105, to reduce post-traumatic pathobiology in an in vitro model of moderate TBI that utilizes an organotypic hippocampal slice culture. NTS-105 inhibited activation of the androgen receptor and the mineralocorticoid receptor, partially activated the progesterone B receptor and was not active at the glucocorticoid receptor. Treatment with NTS-105 starting one hour after injury decreased post-traumatic cell death in a dose-dependent manner, with 10 nM NTS-105 being most effective. Post-traumatic administration of 10 nM NTS-105 also prevented deficits in long-term potentiation (LTP) without adversely affecting neuronal activity in naïve cultures. We propose that the high potency pleiotropic action of NTS-105 beneficial effects at multiple receptors (e.g. androgen, mineralocorticoid and progesterone) provides significant mechanistic advantages over native neurosteroids such as progesterone, which lacked clinical success for the treatment of TBI. Our results suggest that this pleiotropic pharmacology may be a promising strategy for the effective treatment of TBI, and future studies should test its efficacy in pre-clinical animal models of TBI.

Pharmacological Characterization of a Novel Neuroactive Steroid Prodrug, NTS-104, and Its Neuroprotective Activity in Experimental Stroke Models.

BACKGROUND: Ischemic stroke affects about 700 000 patients per year in the United States, and to date, there are no effective pharmacological agents that promote recovery. Here, we studied the pharmacokinetics, pharmacodynamics, and efficacy of NTS-105, a novel neuroactive steroid, and NTS-104, a prodrug of NTS-105, in 2 models of ischemic stroke. METHODS: The pharmacodynamics and pharmacokinetics of NTS-104/105 were investigated in naive and stroke rats, and models of embolic and transient middle cerebral artery occlusion were used to investigate the dose-related effects of NTS-104. All rats were randomly assigned into the experimental groups, and all outcome measurements were performed blindly. RESULTS: Blood plasma and brain pharmacokinetic analysis revealed that NTS-104 rapidly converted to NTS-105, which reached peak concentration at ≈1 hour after dosing and distributed similarly to normal and ischemic brains. NTS-104 administration 4 hours after embolic middle cerebral artery occlusion led to a dose-dependent improvement of neurological outcomes and a dose-dependent reduction of infarct volumes relative to vehicle-treated animals. A single dose level study confirmed that NTS-104 administered 4 hours after transient middle cerebral artery occlusion was also neuroprotective. Quantitative ELISA revealed that NTS-104 treatment resulted in time- and dose-dependent changes in AKT activation and cytokine levels within the ischemic brain, which included reductions of IL-6, VEGF, ICAM-1, IL-1ß, MCP-1, RAGE, and GM-CSF. Time- and dose-dependent reductions in IL-6 and GM-CSF were also observed in the plasma along with an elevation of galectin-1. CONCLUSIONS: NTS-104 is a novel prodrug that converts to a novel neuroactive steroid, NTS-105, which improves functional outcomes in experimental ischemic stroke models.

Multiple-dose ponezumab for mild-to-moderate Alzheimer's disease: Safety and efficacy.

INTRODUCTION: Multiple intravenous doses of ponezumab, an anti-amyloid antibody, were evaluated in subjects with mild-to-moderate Alzheimer's disease (AD). METHODS: In part A, 77 subjects were randomized to ponezumab 0.1, 0.5, or 1 mg/kg (75 treated) and 26 to placebo (24 treated). In part B, 63 subjects were randomized and treated with ponezumab 3 or 8.5 mg/kg and 32 with placebo. Subjects received 10 infusions over 18 months and were followed for 6 months thereafter. RESULTS: Ponezumab was generally safe and well tolerated. Most common adverse events were fall (16.7% ponezumab, 21.4% placebo), headache (13.8%, 21.4%), and cerebral microhemorrhage (13.8%, 19.6%). Plasma ponezumab increased dose-dependently with limited accumulation. Cerebrospinal fluid penetration was low. Plasma Aß1-x and Aß1-40 showed robust increases, but cerebrospinal fluid biomarkers showed no dose response. Ponezumab had no effects on cognitive/functional outcomes or brain volume. CONCLUSIONS: Multiple-dose ponezumab was generally safe, but not efficacious, in mild-to-moderate AD.

Development of a straightforward and sensitive scale for MCI and early AD clinical trials.

BACKGROUND: Although the Clinical Dementia Rating Scale-Sum of Boxes score (CDR-SB) is a widely accepted and commonly used global scale, validated clinical endpoints of cognitive changes are unavailable in the predementia stages of Alzheimer's disease (AD), and a new clinical assessment with reliability and sensitivity is needed in the mild cognitive impairment (MCI) population. METHODS: Using Alzheimer's Disease Neuroimaging Initiative (ADNI)-1/GO data, signal-to-noise ratios (SNRs) were calculated to quantify the sensitivity of a measure for detecting disease progression and hypothetical treatment effects. All possible combinations of selected sensitive measures were assessed for developing composite scores. The analyses were performed in the MCI population and subpopulations enriched by apolipoprotein E4 (APOE ε4), hippocampal volume, and cerebrospinal fluid ß-amyloid. RESULTS: The best composite score was "Word Recall + Delayed Word Recall + Orientation + CDR-SB + FAQ", more sensitive than 13-item Alzheimer's Disease Assessment Scale-cognitive subscale or CDR-SB. CONCLUSION: The proposed composite score derived from the existing clinical endpoints demonstrated higher sensitivity in the MCI population and is easy to implement and standardize across studies.

A multicenter, double-blind, placebo-controlled trial of the PDE9A inhibitor, PF-04447943, in Alzheimer's disease.

BACKGROUND: PF-04447943 is a potent, selective phosphodiesterase 9A (PDE9A) inhibitor that elevates guanoscine 3',5' - cyclic monophosphate (cGMP) in brain and cerebrospinal fluid. PDE9A inhibition enhances synaptic plasticity and improves memory in preclinical cognition models, and prevents decreases in dendritic spine density in transgenic mice that overexpress amyloid precursor protein (APP) leading to high levels of amyloid beta (Aß) production (Tg2576). OBJECTIVE: This Phase 2 multicenter study was designed to assess the efficacy, safety and pharmacokinetics of PF-04447943 compared with placebo in mild to moderate probable Alzheimer's disease (AD). METHODS: Subjects in overall good health with Mini Mental State Examination (MMSE) scores of 14-26 were randomized to 12 weeks treatment with PF-04447943 25 mg q12h (n=91) or placebo (n=100). Concomitant acetylcholinesterase inhibitor or memantine use was excluded. The primary outcome was the Alzheimer's Disease Assessment Scale - cognitive subscale (ADAS-cog). The Neuropsychiatric Inventory (NPI), Clinical Global Impression-Improvement scale (CGI-I) and standard safety measures were secondary outcomes. RESULTS: Completion rates were similar, 87% PF-04447943 vs 92% placebo. At week 12 the mean (SE) baseline adjusted decrease from baseline in ADAS cog for PF-04447943-treated patients was -1.91 (0.54). Placebo treated patients had a change of -1.60 (0.50). The difference between treatments was -0.31 (90% CI of -1.52, 0.90). Corresponding values for the NPI were -2.86 (0.72) vs -2.70 (0.67) with a treatment difference of -0.16 (90% CI of -1.78, 1.48). Neither these changes nor the distribution of CGI-I scores were statistically significantly different between groups. The incidence of serious adverse events (AEs) was similar between groups with 2 deaths in the placebo group. The PF-04447943 group reported more gastrointestinal AEs including diarrhea (5.5% vs 3%) and nausea (5.5% vs 1%) and had a higher rate of discontinuation due to AEs (6.6% vs 2%). CONCLUSIONS: Although generally safe and well-tolerated, 12 weeks PF-04447943 treatment did not improve cognition, behavior, and global change compared with placebo.

Safety and pharmacology of a single intravenous dose of ponezumab in subjects with mild-to-moderate Alzheimer disease: a phase I, randomized, placebo-controlled, double-blind, dose-escalation study.

OBJECTIVES: Ponezumab is a humanized antiamyloid beta (Aß) monoclonal antibody designed to treat Alzheimer disease (AD). METHODS: This randomized, double-blind, single-dose-escalation study evaluated the safety, pharmacokinetics, and pharmacodynamics of 0.1, 0.3, 1, 3, and 10 mg/kg ponezumab (n = 4, 4, 4, 6, and 8, respectively) versus placebo (n = 11) after a 2-hour intravenous infusion in subjects with mild-to-moderate AD. Cerebrospinal fluid (CSF) samples were obtained from the 1- and 10-mg/kg groups at baseline and at day 29. The subjects were followed for 1 year. RESULTS: All subjects completed the trial. Ponezumab was well tolerated with no drug-attributed serious adverse events. The most common adverse events were upper respiratory tract infection, headache, and back pain, all mild to moderate. One subject (10 mg/kg) experienced a mild hypersensitivity reaction. Another subject (0.1 mg/kg) demonstrated slight enlargement of a preexisting midbrain lesion. Electrocardiography and laboratory values (including CSF) were unremarkable. No evidence of new microhemorrhage, vasogenic edema, or meningoencephalitis was noted. Plasma maximum observed concentration increased approximately dose proportionally, and the area under the plasma concentration-time profile from time zero extrapolated to infinite time (AUC(inf)) increased slightly more than dose proportionally. Mean terminal half-life was approximately 6 weeks. Two subjects (10 mg/kg) had measurable CSF ponezumab concentrations (~0.5% of plasma values) at day 29. Plasma Aß(1-x) and Aß(1-40) increased dose dependently, and mean CSF Aß(1-x) increased 38% from baseline with 10 mg/kg (P = 0.002 vs placebo). CONCLUSIONS: A 2-hour infusion of 0.1 to 10 mg/kg ponezumab was well tolerated in subjects with mild-to-moderate AD. Plasma pharmacokinetic profile was approximately linear. Plasma Aß increased with dose, and CSF Aß increased at the highest dose, suggesting that intravenous ponezumab alters central Aß levels.

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. RESEARCH DESIGN AND 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). MAIN OUTCOME MEASURES: 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.

Varenicline versus bupropion SR or placebo for smoking cessation: a pooled analysis.

OBJECTIVES: To evaluate varenicline's efficacy for smoking cessation versus bupropion SR and placebo and to explore whether factors typically predictive of abstinence influence varenicline's efficacy versus placebo, as measured by the week 9-12 continuous abstinence rate (CAR9-12). METHODS: Smokers in 2 randomized, placebo-controlled trials received varenicline 1 mg BID (n=696), bupropion SR 150 mg BID (n=671), or placebo (n=685) for 12 weeks. Nontreatment followup lasted 40 weeks. RESULTS: CAR(9-12) was greater for varenicline (44.0%) versus bupropion SR (29.7%; P<0.0001) and placebo (17.7%; P<0.0001). CAR(9-12) for varenicline versus placebo was not affected by age, gender, or nicotine dependence level. CONCLUSIONS: Varenicline was more efficacious than bupropion SR or placebo. Varenicline's efficacy versus placebo was not influenced by factors predictive of abstinence.

Should troponin and creatinine kinase be routinely measured after vascular surgery?

The current guidelines for the evaluation and prediction of adverse cardiovascular events (CVEs) following vascular surgery in high-risk patients recommends serial electrocardiograms (ECGs) but not biomarkers such as cTn-I and CK-MB. The objective of this study was to determine whether biomarkers should be routinely measured in high-risk patients undergoing vascular surgery. A multicenter, prospective study with investigators blinded to core laboratory results was conducted. cTn-I and CK-MB were obtained on the day of surgery, as well as 24 hours, 72 hours and 120 hours after surgery, 24 hours prior to planned hospital discharge and at the onset of symptoms of a suspected CVE. The CVE was adjudicated by an endpoint committee using ECG, biomarker and symptoms data and was defined as cardiac death or myocardial infarction (MI) occurring up to 30 days after surgery. A total of 784 patients, with a mean age of 70.1 (SD +/- 9.8), underwent vascular surgery. Of the 83 patients with a CVE, cTn-I was positive in 42 and CK-MB was positive in 29 on or before the day of the CVE. The number of patients not classified as having a CVE but positive for elevation of cTn-I or CK-MB was 64 and 20, respectively. cTn-I was more sensitive than CK-MB (50.6% versus 34.9%) for predicting a CVE. The optimum time for measuring cTn-I after surgery with the highest positive predictive value was 24 hours. In conclusion, these data support routine serial measurement of cTn-I after vascular surgery.

A randomized, placebo-controlled trial of varenicline, a selective alpha4beta2 nicotinic acetylcholine receptor partial agonist, as a new therapy for smoking cessation in Asian smokers.

BACKGROUND: Rates of smoking in East Asian men range from >35% to >60%, and are increasing in women and the young. OBJECTIVE: This study evaluated the efficacy and tolerability of 1 mg BID varenicline, a novel alpha4beta2 nicotinic acetylcholine receptor partial agonist, for smoking cessation in smokers in Taiwan and Korea. METHODS: A randomized, double-blind, placebo-controlled, 12-week treatment, 12-week follow-up trial was conducted at 5 sites each in Korea and Taiwan. Eligible subjects, smoking >or=10 cigarettes/d, received brief smoking-cessation counseling and were randomly assigned in a 1:1 ratio to varenicline 1 mg BID (titrated during the first week) or placebo. Smoking status was established by self-report and confirmed at clinic visits by end-expiratory carbon monoxide or= 5% for varenicline were nausea (43.7% for varenicline vs 11.3% placebo), insomnia (15.1% vs 13.7%), increased appetite (7.9% vs 6.5%), constipation (7.1% vs 2.4%), anxiety (5.6% vs 2.4%), and abnormal dreams (5.6% vs 0.8%). Adverse events resulted in <10% treatment discontinuations overall. CONCLUSION: Varenicline was an efficacious and well-tolerated pharmacotherapy for smoking cessation in this group of Asian smokers over a 12-week treatment period, and its effects persisted for a further 12-week follow-up period.

A double-blind study evaluating the long-term safety of varenicline for smoking cessation.

OBJECTIVE: We assessed the safety of long-term varenicline administration for smoking cessation. METHODS: In this randomized, double-blind, multicenter trial, eligible adult smokers (18-75 years) who smoked an average of > or =10 cigarettes/day were randomized to either varenicline 1 mg twice daily (BID) or placebo for 52 weeks. Subjects made weekly clinic visits until week 8, and then every 4 weeks until week 52, with a follow-up visit at week 53. The target quit date was the morning of the week 1 clinic visit. Brief counseling was provided at each visit, and vital signs, adverse events (AEs), and smoking status were documented. Other laboratory measures were collected at specified visits. RESULTS: A total of 251 subjects were randomized to varenicline and 126 to placebo. Approximately half of the subjects in each arm completed the study (53.8% varenicline; 46.8% placebo). Treatment-emergent AEs were observed in 96.4% of varenicline- and 82.5% of placebo-treated subjects during the study. Common varenicline-associated AEs were nausea (40.2%), abnormal dreams (22.7%), and insomnia (19.1%). Most AEs were considered mild or moderate in intensity. AEs leading to discontinuation of varenicline treatment included nausea (7.6%), insomnia (3.2%), and abnormal dreams (2.4%). A single varenicline-related serious AE, bilateral subcapsular cataracts, was observed. At week 52, 7-day point prevalence abstinence rates were 36.7% (varenicline) and 7.9% (placebo). CONCLUSIONS: Varenicline 1 mg BID can be safely administered for up to 1 year. Varenicline was also a more effective smoking cessation aid than placebo throughout the study, supporting both its short- (12-week) and long-term (52-week) efficacy.

Efficacy and safety of the novel selective nicotinic acetylcholine receptor partial agonist, varenicline, for smoking cessation.

BACKGROUND: The selective nicotinic acetylcholine receptor partial agonist, varenicline tartrate, represents a novel type of therapy for smoking cessation. This study evaluated the efficacy, safety, and tolerability of 4 varenicline dose regimens, 2 with progressive dosing over the first week (eg, titrated) and 2 with a fixed dosing schedule (eg, non-titrated), for promoting smoking cessation. METHODS: This multicenter, double-blind, placebo-controlled study randomized healthy smokers (aged 18-65 years) to varenicline tartrate, 0.5 mg twice daily nontitrated (n = 129), 0.5 mg twice daily titrated (n = 130), 1.0 mg twice daily nontitrated (n = 129), 1.0 mg twice daily titrated (n = 130), or placebo (n = 129) for 12 weeks to aid in smoking cessation. A 40-week follow-up period assessed long-term efficacy. The primary efficacy measures were the carbon monoxide-confirmed 4-week continuous quit rates by pooled dosage group for weeks 4 through 7 and 9 through 12 and the continuous abstinence rates for weeks 9 through 52. RESULTS: Weeks 9 through 12 continuous quit rates were greater in the 1.0-mg group (49.4%) and the 0.5-mg group (44.0%) vs placebo (11.6%; P<.001 vs both doses). Weeks 9 through 52 abstinence rates were greater in the 1.0-mg group (22.4%; P<.001) and the 0.5-mg group (18.5%; P<.001) vs placebo (3.9%). Varenicline was generally well tolerated, with nausea occurring in 16% to 42% of varenicline-treated subjects. Reports of nausea were lower for the titrated vs nontitrated dosing and infrequently led to medication discontinuation. CONCLUSION: Varenicline tartrate, 0.5 mg and 1.0 mg twice daily, is efficacious for smoking cessation.

Varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs sustained-release bupropion and placebo for smoking cessation: a randomized controlled trial.

CONTEXT: The alpha4beta2 nicotinic acetylcholine receptors (nAChRs) are linked to the reinforcing effects of nicotine and maintaining smoking behavior. Varenicline, a novel alpha4beta2 nAChR partial agonist, may be beneficial for smoking cessation. OBJECTIVE: To assess efficacy and safety of varenicline for smoking cessation compared with sustained-release bupropion (bupropion SR) and placebo. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind, parallel-group, placebo- and active-treatment-controlled, phase 3 clinical trial conducted at 19 US centers from June 19, 2003, to April 22, 2005. Participants were 1025 generally healthy smokers (> or =10 cigarettes/d) with fewer than 3 months of smoking abstinence in the past year, 18 to 75 years old, recruited via advertising. INTERVENTION: Participants were randomly assigned in a 1:1:1 ratio to receive brief counseling and varenicline titrated to 1 mg twice per day (n = 352), bupropion SR titrated to 150 mg twice per day (n = 329), or placebo (n = 344) orally for 12 weeks, with 40 weeks of nondrug follow-up. MAIN OUTCOME MEASURES: Primary outcome was the exhaled carbon monoxide-confirmed 4-week rate of continuous abstinence from smoking for weeks 9 through 12. A secondary outcome was the continuous abstinence rate for weeks 9 through 24 and weeks 9 through 52. RESULTS: For weeks 9 through 12, the 4-week continuous abstinence rates were 44.0% for varenicline vs 17.7% for placebo (odds ratio [OR], 3.85; 95% confidence interval [CI], 2.70-5.50; P<.001) and vs 29.5% for bupropion SR (OR, 1.93; 95% CI, 1.40-2.68; P<.001). Bupropion SR was also significantly more efficacious than placebo (OR, 2.00; 95% CI, 1.38-2.89; P<.001). For weeks 9 through 52, the continuous abstinence rates were 21.9% for varenicline vs 8.4% for placebo (OR, 3.09; 95% CI, 1.95-4.91; P<.001) and vs 16.1% for bupropion SR (OR, 1.46; 95% CI, 0.99-2.17; P = .057). Varenicline reduced craving and withdrawal and, for those who smoked while receiving study drug, smoking satisfaction. No sex differences in efficacy for varenicline were observed. Varenicline was safe and generally well tolerated, with study drug discontinuation rates similar to those for placebo. The most common adverse events for participants receiving active-drug treatment were nausea (98 participants receiving varenicline [28.1%]) and insomnia (72 receiving bupropion SR [21.9%]). CONCLUSION: Varenicline was significantly more efficacious than placebo for smoking cessation at all time points and significantly more efficacious than bupropion SR at the end of 12 weeks of drug treatment and at 24 weeks. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00141206.

Efficacy of varenicline, an alpha4beta2 nicotinic acetylcholine receptor partial agonist, vs placebo or sustained-release bupropion for smoking cessation: a randomized controlled trial.

CONTEXT: Varenicline, a partial agonist at the alpha4beta2 nicotinic acetylcholine receptor, has the potential to aid smoking cessation by relieving nicotine withdrawal symptoms and reducing the rewarding properties of nicotine. OBJECTIVE: To determine the efficacy and safety of varenicline for smoking cessation compared with placebo or sustained-release bupropion (bupropion SR). DESIGN, SETTING, AND PARTICIPANTS: A randomized, double-blind, placebo-controlled trial conducted between June 2003 and March 2005 at 14 research centers with a 12-week treatment period and follow-up of smoking status to week 52. Of 1413 adult smokers who volunteered for the study, 1027 were enrolled; 65% of randomized participants completed the study. INTERVENTION: Varenicline titrated to 1 mg twice daily (n = 344) or bupropion SR titrated to 150 mg twice daily (n = 342) or placebo (n = 341) for 12 weeks, plus weekly brief smoking cessation counseling. MAIN OUTCOME MEASURES: Continuous abstinence from smoking during the last 4 weeks of treatment (weeks 9-12; primary end point) and through the follow-up period (weeks 9-24 and 9-52). RESULTS: During the last 4 weeks of treatment (weeks 9-12), 43.9% of participants in the varenicline group were continuously abstinent from smoking compared with 17.6% in the placebo group (odds ratio [OR], 3.85; 95% confidence interval [CI], 2.69-5.50; P<.001) and 29.8% in the bupropion SR group (OR, 1.90; 95% CI, 1.38-2.62; P<.001). For weeks 9 through 24, 29.7% of participants in the varenicline group were continuously abstinent compared with 13.2% in the placebo group (OR, 2.83; 95% CI, 1.91-4.19; P<.001) and 20.2% in the bupropion group (OR, 1.69; 95% CI, 1.19-2.42; P = .003). For weeks 9 through 52, 23% of participants in the varenicline group were continuously abstinent compared with 10.3% in the placebo group (OR, 2.66; 95% CI, 1.72-4.11; P<.001) and 14.6% in the bupropion SR group (OR, 1.77; 95% CI, 1.19-2.63; P = .004). Treatment was discontinued due to adverse events by 10.5% of participants in the varenicline group, 12.6% in the bupropion SR group, and 7.3% in the placebo group. The most common adverse event with varenicline was nausea, which occurred in 101 participants (29.4%). CONCLUSIONS: Varenicline is an efficacious, safe, and well-tolerated smoking cessation pharmacotherapy. Varenicline's short-term and long-term efficacy exceeded that of both placebo and bupropion SR. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00143364.

Effect of maintenance therapy with varenicline on smoking cessation: a randomized controlled trial.

CONTEXT: The majority of cigarette smokers who achieve abstinence relapse within the first year and require many attempts before achieving permanent abstinence. Evidence to support pharmacological treatment for relapse prevention is insufficient. OBJECTIVE: To determine whether smokers who quit after 12 weeks of treatment with varenicline, a selective alpha4beta2 nicotinic acetylcholine receptor partial agonist, maintain greater continuous abstinence rates (defined as not a single "puff" of a cigarette) than placebo controls during an additional 12 weeks of treatment and until 52 weeks after treatment initiation. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial conducted at multiple medical clinics in 7 countries with follow-up to 52 weeks after study baseline. Of 1927 cigarette smokers recruited between April 2003 and February 2004 and treated for 12 weeks with open-label varenicline titrated to 1 mg twice per day, 1236 (64.1%) did not smoke, use tobacco, or use nicotine replacement therapy during the last week of treatment and 62.8% (n = 1210) were randomized to additional treatment or placebo. INTERVENTION: Participants were randomly assigned to receive either double-blind varenicline, 1 mg twice per day (n = 603), or placebo (n = 607) for an additional 12 weeks. MAIN OUTCOME MEASURES: Carbon monoxide-confirmed continued abstinence during weeks 13 to 24 and weeks 13 to 52 of the study. RESULTS: The carbon monoxide-confirmed continuous abstinence rate was significantly higher for the varenicline group than for the placebo group for weeks 13 to 24 (70.5% vs 49.6%; odds ratio [OR], 2.48; 95% confidence interval [CI], 1.95-3.16; P<.001) as well as for weeks 13 to 52 (43.6% vs 36.9%; OR, 1.34; 95% CI, 1.06-1.69; P = .02). Adverse events reported in the open-label period were mostly mild; no difference in adverse events between varenicline and placebo was observed during the double-blind period. CONCLUSIONS: Smokers who achieved abstinence for at least 7 days at the end of 12 weeks of open-label varenicline treatment and were randomized to receive an additional 12 weeks of varenicline treatment showed significantly greater continuous abstinence in weeks 13 to 24 compared with placebo. This advantage was maintained through the nontreatment follow-up to week 52. Varenicline may be an efficacious, safe, and well-tolerated agent for maintaining abstinence from smoking. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00143286.