Efficacy and Safety of Esmethadone (REL-1017) in Patients With Major Depressive Disorder and Inadequate Response to Standard Antidepressants: A Phase 3 Randomized Controlled Trial.

Objective: To test esmethadone (REL-1017) as adjunctive treatment in patients with major depressive disorder (MDD) and inadequate response to standard antidepressants.Methods: In this phase 3, double-blind, placebo-controlled trial, outpatients with MDD (DSM-5) were randomized to daily oral esmethadone (75 mg on day 1, followed by 25 mg daily on days 2 through 28) or placebo between December 2020 and December 2022. The primary efficacy measure was change from baseline (CFB) to day 28 in the Montgomery-Asberg Depression Rating Scale (MADRS) score. The intent-to-treat (ITT) population included all randomized participants. The per-protocol (PP) population included completers without major protocol deviations impacting assessment. Post hoc analyses included participants with severe depression (baseline MADRS score ≥35).Results: For the ITT analysis (n = 227), mean CFB was 15.1 (SD 11.3) for esmethadone (n = 113) and 12.9 (SD 10.4) for placebo (n = 114), with a mean difference (MD) of 2.3, which was not statistically significant (P = .154; Cohen effect size [ES] = 0.21). Remission rates were 22.1% and 13.2% (P = .076), and response rates were 39.8% and 27.2% (P = .044) with esmethadone and placebo, respectively. For the PP analysis (n = 198), mean CFB was 15.6 (SD 11.2) for esmethadone (n = 101) and 12.5 (SD 9.9) for placebo (n = 97), with an MD of 3.1 (P = .051; ES =0.29). In post hoc analyses of patients with baseline MADRS ≥35 in the ITT population (n = 112), MD was 6.9; P = .0059; ES = 0.57, and for the PP population (n = 98), MD was 7.9; P = .0015; ES = 0.69. Adverse events (AEs) were predominantly mild or moderate and transient, with no significant differences between groups.Conclusions: The primary end point was not met. Esmethadone showed stronger efficacy in PP than in ITT analyses, with the discrepancy not attributable to AEs impacting treatment adherence. Significant efficacy occurred in post hoc analyses of patients with severe depression. Esmethadone was well tolerated, consistent with prior studies.Trial Registration: ClinicalTrials.gov identifier: NCT04688164.

The novel uncompetitive NMDA receptor antagonist esmethadone (REL-1017) has no meaningful abuse potential in recreational drug users.

Esmethadone (REL-1017) is the opioid-inactive dextro-isomer of methadone and a low-affinity, low-potency uncompetitive NMDA receptor antagonist. In a Phase 2, randomized, double-blind, placebo-controlled trial, esmethadone showed rapid, robust, and sustained antidepressant effects. Two studies were conducted to evaluate the abuse potential of esmethadone. Each study utilized a randomized, double-blind, active-, and placebo-controlled crossover design to assess esmethadone compared with oxycodone (Oxycodone Study) or ketamine (Ketamine Study) in healthy recreational drug users. Esmethadone 25 mg (proposed therapeutic daily dose), 75 mg (loading dose), and 150 mg (Maximum Tolerated Dose) were evaluated in each study. Positive controls were oral oxycodone 40 mg and intravenous ketamine 0.5 mg/kg infused over 40 min. The Ketamine study included oral dextromethorphan 300 mg as an exploratory comparator. The primary endpoint was maximum effect (Emax) for Drug Liking, assessed using a bipolar 100-point visual analog scale (VAS). A total of 47 and 51 participants completed the Oxycodone Study and the Ketamine Study, respectively (Completer Population). In both studies, esmethadone doses ranging from therapeutic (25 mg) to 6 times therapeutic (150 mg) had a meaningful and statistically significantly (p < 0.001) lower Drug Liking VAS Emax compared with the positive control. Results were consistent for all secondary endpoints in both studies. In both studies, all doses of esmethadone were statistically equivalent to placebo on Drug Liking VAS Emax (p < 0.05). In the Ketamine Study, Drug Liking VAS Emax scores for esmethadone at all tested doses were significantly lower vs. dextromethorphan (p < 0.05) (exploratory endpoint). These studies indicate no meaningful abuse potential for esmethadone at all tested doses.

Safety and Efficacy of Lofexidine for Medically Managed Opioid Withdrawal: A Randomized Controlled Clinical Trial.

OBJECTIVES: To investigate the safety and efficacy of lofexidine for treating opioid withdrawal syndrome (OWS) and facilitating completion of opioid withdrawal. METHODS: A multicenter, double-blind, placebo-controlled study was conducted at 18 US centers from June 2013 to December 2014. Participants (n = 603) aged ≥18 years, dependent on short-acting opioids, and seeking withdrawal treatment, randomized 3:3:2 to receive lofexidine 2.88 mg/d (n = 222), lofexidine 2.16 mg/d (n = 230), or placebo (n = 151) for 7 days. Primary outcome was the Short Opiate Withdrawal Scale of Gossop (SOWS-Gossop) scores rating withdrawal symptoms over days 1 to 7. RESULTS: Participants were of mean age, 35 years; 71% male. Pairwise differences in overall SOWS-Gossop log-transformed least squares means were statistically significant for lofexidine 2.16 mg (difference, -0.21; 95% CI, -0.37 to -0.04; P = 0.02) and 2.88 mg (-0.26; 95% CI, -0.44 to -0.09; P = 0.003) compared with placebo. Fewer than half of participants in both groups completed the study. Completion rates for lofexidine 2.16 mg (41.5%; odds ratio [OR], 1.85; P = 0.007) and 2.88 mg (39.6%; OR, 1.71; P = 0.02) were significantly better compared with placebo (27.8%). Overall adverse event (AE) rates were similar across groups. Common AEs for lofexidine included orthostatic hypotension, hypotension, and bradycardia, but resulted in few study discontinuations. CONCLUSIONS: Lofexidine 2.16 mg and 2.88 mg significantly reduced symptoms of OWS versus placebo, and increased absolute rates of completing the 7-day study by 14% and 12%, respectively (a relative increase of 85% and 71%). Data suggest that lofexidine is a generally safe and effective nonopioid treatment for opioid withdrawal. Lofexidine could serve as a withdrawal treatment option when a nonopioid agent is preferred or required, when agonist-assisted withdrawal is unavailable, when agonist discontinuation caused OWS, and during induction into maintenance treatment with opioid agonists or antagonists. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01863186.

Bupropion for the treatment of methamphetamine dependence.

Bupropion was tested for efficacy in increasing weeks of abstinence in methamphetamine-dependent patients, compared to placebo. This was a double-blind placebo-controlled study, with 12 weeks of treatment and a 30-day follow-up. Five outpatient substance abuse treatment clinics located west of the Mississippi participated in the study. One hundred and fifty-one treatment-seekers with DSM-IV diagnosis of methamphetamine dependence were consented and enrolled. Seventy-two participants were randomized to placebo and 79 to sustained-release bupropion 150 mg twice daily. Patients were asked to come to the clinic three times per week for assessments, urine drug screens, and 90-min group psychotherapy. The primary outcome was the change in proportion of participants having a methamphetamine-free week. Secondary outcomes included: urine for quantitative methamphetamine, self-report of methamphetamine use, subgroup analyses of balancing factors and comorbid conditions, addiction severity, craving, risk behaviors for HIV, and use of other substances. The generalized estimating equation regression analysis showed that, overall, the difference between bupropion and placebo groups in the probability of a non-use week over the 12-week treatment period was not statistically significant (p=0.09). Mixed model regression was used to allow adjustment for baseline factors in addition to those measured (site, gender, level of baseline use, and level of symptoms of depression). This subgroup analysis showed that bupropion had a significant effect compared to placebo, among male patients who had a lower level of methamphetamine use at baseline (p<0.0001). Comorbid depression and attention-deficit/hyperactivity disorder did not change the outcome. These data suggest that bupropion, in combination with behavioral group therapy, was effective for increasing the number of weeks of abstinence in participants with low-to-moderate methamphetamine dependence, mainly male patients, regardless of their comorbid condition.

The NIDA Methamphetamine Clinical Trials Group: a strategy to increase clinical trials research capacity.

AIMS: In order to increase the number of investigative teams and sites conducting research on pharmacological treatments for methamphetamine use disorders, the National Institute on Drug Abuse (NIDA) established an infrastructure of clinical sites in areas where methamphetamine addiction is prevalent. This multi-site infrastructure would serve to run multiple Phases II and III protocols effectively and expeditiously. METHODS: NIDA collaborated with investigators from the University of California at Los Angeles (UCLA) to set up the Methamphetamine Clinical Trials Group (MCTG). This paper describes the development process, as well as data from a test trial to assess the capability of research-naive sites to recruit research participants and conduct study procedures according to research protocol. Subsequent trials are also described. RESULTS: A total of 151 candidates signed consent; 65 individuals were enrolled and 35 (53.8%) completed the 12 weeks' behavioral trial. Self-reported substance use report (SUR) showed comparable use of methamphetamine across sites with the individual site means ranging from 59% (site 5) to 80% (site 3). Drug use as measured by urinalysis was greatly reduced at week 13 compared to the baseline measure; the average rate of methamphetamine-free urine samples across all participants in sites at week 13 was 53%. The highest percentage of methamphetamine-free samples was 85% at site 5; the lowest was at site 1 (40%). Addiction severity index (ASI) composite scores at baseline and protocol completion for all participants demonstrated improvement in all categories over time, except for the medical composite score. The largest composite score reduction in baseline-protocol completion was in the drug domain (0.23 versus 0.15). The changes in the ASI scores from baseline to week 13 were consistent across all five sites. CONCLUSIONS: Outcomes of the behavioral trial indicated that the MCTG recruited well; collected study data accurately and reliably; and created a vehicle that can assess promising pharmacotherapies for methamphetamine addiction treatment medications. The MCTG strategy appears to be a feasible approach to increase NIDA's capacity to conduct clinical trials to evaluate potential pharmacotherapies for methamphetamine addiction.

A phase III, randomized, multi-center, double blind, placebo controlled study of safety and efficacy of lofexidine for relief of symptoms in individuals undergoing inpatient opioid withdrawal.

BACKGROUND: Lofexidine is an alpha-2-adrenergic receptor agonist approved in the United Kingdom (UK) for the treatment of opioid withdrawal symptoms. Lofexidine has demonstrated better efficacy than placebo for reducing opioid withdrawal symptoms in patients undergoing opioid withdrawal with less reported hypotension than clonidine. METHODS: Designed as an FDA registration trial, this 8-day, randomized, double-blind, placebo-controlled, parallel-group study in 264 patients dependent on short-acting opioids evaluated the efficacy of lofexidine hydrochloride in reducing withdrawal symptoms in patients undergoing opioid withdrawal. The primary efficacy measures were SOWS-Gossop on Day 3 and time-to-dropout. Secondary endpoints included the proportion of participants who were completers; area under the 5-day SOWS-Gossop - time curve (i.e., AUC1-5), and daily mean SOWS-Gossop, OOWS-Handelsman, MCGI (subject and rater), and VAS-E scores. Participants received lofexidine HCl 3.2mg daily in four divided doses or matching placebo on Days 1-5, followed by 2days of placebo. RESULTS: Lofexidine significantly decreased mean Day 3 SOWS scores compared to placebo, 6.32 versus 8.67, respectively, p=0.0212. Fewer lofexidine patients were early terminators compared to placebo (59 versus 80, respectively); and non-completers in the lofexidine group remained in the study longer than those assigned to placebo (p=0.0034). Secondary endpoints consistently favored lofexidine. Lofexidine was well tolerated in this trial. CONCLUSION: Lofexidine significantly decreased SOWS scores compared to placebo and demonstrated better retention rates in participants undergoing opioid withdrawal. Lofexidine potentially offers a useful non-opioid alternative to treat opioid withdrawal symptoms.

Involving the pharmaceutical and biotech communities in medication development for substance abuse.

Pharmacotherapy as adjunctive treatment is an integral part of the strategy for treating substance abuse. Although there are several approved drugs for the treatment of opioid, alcohol, and nicotine dependence, the pharmaceutical industry, for a variety of reasons, has been reluctant to enter this area to develop medications for substance abuse indications. Therefore, in 1990, a Medication Development Program was established by NIDA to carry out and assist in stimulating development of new pharmacotherapies. It is vital for NIDA to provide clear leadership and establish a collaborative working relationship with the pharmaceutical industry, providing scientific, development, and financial assistance, depending on the size, resources, and expertise of the company. An important NIDA role in this effort is setting standards, such as establishing Target Product Profiles (TPPs), predictive decision trees for selection of clinical candidates, and animal models to evaluate safety and potential effectiveness prior to human studies. NIDA can further establish standards for clinical studies, including Proof of Concept (PoC), Phase 2 (or Learning) trials to establish initial proof of safety and effectiveness, and Phase 3 (or Confirming) trials to validate Phase 2 findings. NIDA and other government agencies need to work to improve industry incentives to participate in medication development for substance abuse. Specific incentives, such as market exclusivity and patent extension, as provided in BioShield and pediatric drug legislation, should be strongly considered. NIDA can further assist industry to navigate the regulatory and, if needed, controlled substance scheduling processes, by establishing a true Federal partnership between NIDA, FDA, and DEA.

Impact of formulation on the abuse liability, safety and regulation of medications: the expert panel report.

A scientific meeting was held in April 2005 to consider how the formulation of medications might impact on their potential for abuse. The background papers prepared for this meeting, as well as abstracts of volunteered presentations, are published in this supplemental issue of Drug and Alcohol Dependence. This paper is the Expert Panel Report summarizing the discussions held following the formal presentations and including the suggested recommendations for additional research that emerged from these discussions. There was overwhelming consensus that formulation does play a role in prescription drug abuse, i.e., a formulation of an abused substance can be developed that will decrease its abuse potential, and several examples were cited. Nevertheless, it is imperative that new formulations have similar efficacy and in no way compromise medication access to doctors and patients. However, there was also consensus that a great deal of research and discussion was needed to fully implement a program of risk management through reformulation of existing products or tailoring the formulation of new products to retain clinical efficacy and safety while minimizing potential for abuse. Those who need to take part in this discussion include scientific groups, pharmaceutical companies, as well as governmental and regulatory agencies. The areas where more research is needed include development of standards for assessing tamper-resistance, improved animal models that can address formulation-related variables (e.g., onset, duration), the redesign of human laboratory studies providing appropriate models for comparing formulations, and improved post-marketing surveillance. Finally, knowledge and experience are needed to translate scientific work into a predictable, transparent and reliable regulatory process.

Psychometric evaluation of the 10-item Short Opiate Withdrawal Scale-Gossop (SOWS-Gossop) in patients undergoing opioid detoxification.

INTRODUCTION: The Short Opiate Withdrawal Scale (SOWS)-Gossop is a 10-item questionnaire developed to evaluate opioid withdrawal symptom severity. The scale was derived from the original 32-item Opiate Withdrawal Scale in order to reduce redundancy while providing an equally sensitive measure of opioid withdrawal symptom severity appropriate for research and clinical practice. The objective of this study was to examine the psychometric properties and provide score interpretation guidelines for the SOWS-Gossop 10-item version. METHODS: Blinded, pooled data from two trials assessing the efficacy of lofexidine hydrochloride in reducing withdrawal symptoms in patients undergoing opioid detoxification were used to evaluate the quantitative psychometric properties and score interpretation of the SOWS-Gossop. RESULTS: Five hundred fifty-five (N=555) observations were available at baseline with numbers decreasing to n=213 at day 7. Mean (standard deviation) SOWS-Gossop scores were 10.4 (6.86) at baseline, 8.7 (6.49) on day 1, 10.5 (7.21) on day 2, and 3.1 (3.95) on day 7. Confirmatory factor analysis indicated that the SOWS-Gossop items loaded on a single factor consistent with a single total score. Intra-class correlations (95% confidence interval) were 0.78 (0.70-0.85) between baseline and day 1, 0.84 (0.79-0.89) between days 4 and 5, and 0.88 (0.83-0.91) between days 6 and 7, demonstrating good test-retest reliability. Mean SOWS-Gossop scores varied significantly (p<0.0001) by Modified Clinical Global Impression severity groups supporting known-groups validity. Most correlations with conceptually similar instruments were over 0.4, providing evidence of construct validity. Results suggest that a change score of approximately 2-4 points is likely a small but meaningful improvement on the SOWS-Gossop Total Score. CONCLUSIONS: The findings of this study indicate that the SOWS-Gossop includes concepts that are relevant to patients' experiences with opioid withdrawal and has excellent psychometric properties. The SOWS-Gossop is an appropriate, precise, and sensitive measure to evaluate the symptoms of acute opioid withdrawal in research or clinical settings.

Real-world efficacy of prescription and over-the-counter nicotine replacement therapy.

AIMS: To assess smoking cessation rates achieved with nicotine gum and patch in simulated over-the-counter (OTC) and actual prescription (Rx) settings. DESIGN: Separate open-label studies with gum and patch in OTC and Rx settings. PARTICIPANTS: There were multiple samples: OTC gum: 2981 smokers; OTC patch: 2367; Rx gum: 324; Rx patch: 669. INTERVENTIONS: All smokers received active nicotine replacement. In the OTC setting, smokers self-selected doses of nicotine gum (2 or 4 mg Nicorette) or patch (21, 14 or 7 mg NicoDerm CQ). No intervention was provided. In the Rx setting, smokers were prescribed gum or patch by their physician. MEASUREMENTS: Biochemically verified continuous smoking abstinence was assessed at 6 weeks (28-day abstinence) and 6 months. FINDINGS: OTC success rates were consistently higher than Rx rates: differences were significant at 6 weeks for both patch [OR = 1.45 (1.05-1.98)] and gum [OR 2.92 (1.58-5.40)], and remained significant at 6 months for patch [OR = 3.63: (1.74-7.61)] but not gum [OR = 1.37: (0.73-2.58)]. Among OTC gum users. 16.1% were abstinent at 6 weeks and 8.4% at 6 months. For Rx gum users, abstinence rates were 7.7% at 6 weeks and 7.7% at 6 months. With OTC patch, 19.0% were abstinent at 6 weeks and 9.2% at 6 months. With Rx patch. abstinence rates were 16.0% at 6 weeks and 3.0% at 6 months. CONCLUSIONS: Smoking cessation rates achieved with nicotine gum and patch under OTC conditions were as good as those under real-world prescribing conditions.

A multisite, double-blind, placebo-controlled clinical trial to evaluate the safety and efficacy of vigabatrin for treating cocaine dependence.

IMPORTANCE: Cocaine dependence is a significant public health problem, yet no validated pharmacological treatment exists. The potent γ-aminobutyric acid (GABA)ergic medication vigabatrin has previously been shown to be effective in a double-blind single-site study conducted in Mexico. OBJECTIVE: To evaluate the safety and efficacy of vigabatrin for the treatment of cocaine dependence in a U.S. sample. DESIGN AND SETTING: Multisite, randomized, double-blind, placebo-controlled, 12-week clinical trial with follow-up visits at weeks 13, 16, 20, and 24 in 11 U.S. sites. PARTICIPANTS: In total, 186 treatment-seeking participants with cocaine dependence (mean age, 45 years). Approximately 67% were male, and about 60% were of African American race/ethnicity. INTERVENTIONS: Participants received twice-daily doses of vigabatrin (total dosage, 3.0 g/d) or matched placebo, plus weekly computerized cognitive behavioral therapy and biweekly individual counseling for 13 weeks. Contingency management encouraged the provision of urine samples. MAIN OUTCOMES AND MEASURES: The primary outcome measure was the proportion of participants with cocaine abstinence during the last 2 weeks of the 12-week treatment phase as assessed by self-reports and quantitative urine drug screens. The weekly fraction of cocaine use days and the number of drug-free urine samples during weeks 1 through 13 were key secondary measures. RESULTS: No significant differences were observed between the vigabatrin group and the placebo group on the primary outcome measure (P = .67), key secondary measures (P > .99), or other outcome measures. However, while pill counts and self-reports indicated that more than 66% of all participants (and >63% of the vigabatrin group) took more than 70% of their medication, post hoc vigabatrin urine concentration levels suggested that approximately 40% to 60% of patients taking vigabatrin may not have been adherent. This lack of adherence may have obscured any evidence of vigabatrin efficacy. No visual acuity or visual field deterioration occurred in any of the participants. CONCLUSIONS AND RELEVANCE: No protocol-defined differences in efficacy between vigabatrin treatment and placebo were detected for any outcome variable. This may have been due to medication nonadherence or, alternatively, due to the weak efficacy of vigabatrin. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00611130.

Fine-grain analysis of the treatment effect of topiramate on methamphetamine addiction with latent variable analysis.

BACKGROUND: As reported previously, 140 methamphetamine-dependent participants at eight medical centers in the U.S. were assigned randomly to receive topiramate (N=69) or placebo (N=71) in a 13-week clinical trial. The study found that topiramate did not appear to reduce methamphetamine use significantly for the primary outcome (i.e., weekly abstinence from methamphetamine in weeks 6-12). Given that the treatment responses varied considerably among subjects, the objective of this study was to identify the heterogeneous treatment effect of topiramate and determine whether topiramate could reduce methamphetamine use effectively in a subgroup of subjects. METHODS: Latent variable analysis was used for the primary and secondary outcomes during weeks 6-12 and 1-12, adjusting for age, sex, and ethnicity. RESULTS: Our analysis of the primary outcome identified 30 subjects as responders, who either reduced methamphetamine use consistently over time or achieved abstinence. Moreover, topiramate recipients had a significantly steeper slope in methamphetamine reduction and accelerated to abstinence faster than placebo recipients. For the secondary outcomes in weeks 6-12, we identified 40 subjects as responders (who had significant reductions in methamphetamine use) and 65 as non-responders; topiramate recipients were more than twice as likely as placebo recipients to be responders (odds ratio=2.67; p=0.019). Separate analyses of the outcomes during weeks 1-12 yielded similar results. CONCLUSIONS: Methamphetamine users appear to respond to topiramate treatment differentially. Our findings show an effect of topiramate on the increasing trend of abstinence from methamphetamine, suggesting that a tailored intervention strategy is needed for treating methamphetamine addiction.

Topiramate for the treatment of methamphetamine addiction: a multi-center placebo-controlled trial.

AIMS: Topiramate has shown efficacy at facilitating abstinence from alcohol and cocaine abuse. This double-blind, placebo-controlled out-patient trial tested topiramate for treating methamphetamine addiction. DESIGN: Participants (n = 140) were randomized to receive topiramate or placebo (13 weeks) in escalating doses from 25 mg/day [DOSAGE ERROR CORRECTED] to the target maintenance of 200 mg/day in weeks 6-12 (tapered in week 13). Medication was combined with weekly brief behavioral compliance enhancement treatment. SETTING: The trial was conducted at eight medical centers in the United States. PARTICIPANTS: One hundred and forty methamphetamine-dependent adults took part in the trial. MEASUREMENTS: The primary outcome was abstinence from methamphetamine during weeks 6-12. Secondary outcomes included use reduction versus baseline, as well as psychosocial variables. FINDINGS: In the intent-to-treat analysis, topiramate did not increase abstinence from methamphetamine during weeks 6-12. For secondary outcomes, topiramate reduced weekly median urine methamphetamine levels and observer-rated severity of dependence scores significantly. Subjects with negative urine before randomization (n = 26) had significantly greater abstinence on topiramate versus placebo during study weeks 6-12. Topiramate was safe and well tolerated. CONCLUSIONS: Topiramate does not appear to promote abstinence in methamphetamine users but can reduce the amount taken and reduce relapse rates in those who are already abstinent.

Risk management and post-marketing surveillance for the abuse of medications acting on the central nervous system: expert panel report.

The abuse and diversion of medications is a significant public health problem. This paper is part of a supplemental issue of Drug and Alcohol Dependence focused on the development of risk management plans and post-marketing surveillance related to minimizing this problem. The issue is based on a conference that was held in October 2008. An Expert Panel was formed to provide a summary of the conclusions and recommendations that emerged from the meeting involving drug abuse experts, regulators and other government agencies, pharmaceutical companies and professional and other non-governmental organizations. This paper provides a written report of this Expert Panel. Eleven conclusions and 11 recommendations emerged concerning the state of the art of this field of research, the regulatory and public health implications and recommendations for future directions. It is concluded that special surveillance tools are needed to detect the emergence of medication abuse in a timely manner and that risk management tools can be implemented to increase the benefit to risk ratio. The scientific basis for both the surveillance and risk management tools is in its infancy, yet progress needs to be made. It is also important that the unintended consequences of increased regulation and the imposition of risk management plans be minimized.

Efficacy of over-the-counter nicotine patch.

This study aimed to assess the efficacy of the nicotine patch for smoking cessation, under simulated conditions of over-the-counter sale, absent any direct instruction or behavioral treatment. In a randomized, double-blind, placebo-controlled, multicenter study, 567 smokers were randomized to an active nicotine patch (n = 283) or placebo (n = 284). Treatment followed a three-step program of 21 mg/day for 6 weeks, 14 mg/day for 2 weeks and 7 mg/day for 2 weeks. Participants received brief written instructions, an audiotape and a written User's Guide. There was no other intervention and no contact with participants between enrollment and the primary outcome assessment at 6 weeks. Analyses were based on intent to treat, with lost subjects counted as failures, and claimed abstinence was verified by carbon monoxide measures. Use of active patch produced significantly higher abstinence rates. Continuous abstinence rates (subject to a 2-week grace period) for nicotine and placebo were 19.4% and 7.0% at 6 weeks (OR = 3.2; 95% CI 1.8-5.4) and 15.2% and 5.3% at 10 weeks (OR = 3.2; 95% CI 1.7-5.9), respectively. Seven-day point-prevalence rates for nicotine and placebo patches were 26.1% and 7.7% at 6 weeks (OR = 4.2; 95% CI 2.5-7.0) and 23.3% and 7.7% at 10 weeks (OR = 3.6; 95% CI 2.2-6.1), respectively. Reported adverse events were mild and consistent with prior observations of nicotine patch use. The nicotine patch was safe and effective for smoking cessation at least during 10 weeks of treatment under open-sale conditions, without face-to-face instruction or counseling.