This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Study Evaluating The Safety And Efficacy Of Varenicline and Bupropion For Smoking Cessation In Subjects With And Without A History Of Psychiatric Disorders (NCT01456936), a randomized phase 4 study. The primary outcome is Occurrence of Neuropsychiatric (NPS) Adverse Events (AE) - the Primary Study Endpoint.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01456936 |
| Phase | Phase 4 |
| Condition | Smoking Cessation |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 8144 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Participants seeking smoking cessation treatment, including people with and without an established diagnosis of major psychiatric disorder. The safety dataset included participants who received at least a partial dose of study medication.
Intervention
Varenicline tartrate 1mg twice daily, bupropion hydrochloride 150mg twice daily, or a nicotine replacement therapy patch. The registry describes treatment over 12 weeks.
Comparator
Placebo was included as a comparator, alongside the active treatments. The registry describes a randomized, double-blind, active- and placebo-controlled design.
Primary question
How often did participants experience the specified treatment-emergent neuropsychiatric adverse events, and how did that occurrence vary across treatment groups and psychiatric-history cohorts? The record also states that the study assessed smoking-cessation efficacy, but arm-level efficacy results are not reported in the registry record.
The primary safety endpoint combines specified event types and severity thresholds. It includes severe anxiety, depression, feeling abnormal, or hostility, as well as moderate or severe agitation, aggression, delusions, hallucinations, homicidal ideation, mania, panic, paranoia, psychosis, suicidal ideation, suicidal behavior, or completed suicide. The event window begins at the first dose and extends to the last dose, with follow-up through 30 days afterward.
The trial’s stated purpose was to assess the treatments as aids to smoking cessation and characterize neuropsychiatric safety in people with and without a history of psychiatric disorders. The registry record identifies the primary safety question, but does not provide its event results by treatment or cohort. As a result, the treatment-specific magnitude and precision of the primary comparison cannot be described from the reported information.
3. Trial Design
This was a phase 4, randomized, double-blind, parallel-group, multicenter study with active and placebo controls. The registry lists enrollment as 8144. Participants were studied with and without a history of psychiatric disorders. The trial’s stated start was 2011-11, and its primary completion was 2015-01; its status is completed.
The interventions listed in the record were placebo, varenicline tartrate, bupropion hydrochloride, and a nicotine replacement therapy patch. The official title specifies varenicline tartrate 1mg twice daily and bupropion hydrochloride 150mg twice daily over 12 weeks. The primary endpoint’s treatment-emergent window runs from the first dose to the last dose, up to 12 weeks, and then through 30 days after the last dose.
The record describes placebo treatment for all three study drugs in the placebo group, including blinded placebo for the varenicline, bupropion, and transdermal nicotine patch. The available arm-description text is incomplete, so further details about how each active treatment was administered or matched for blinding are not reported in the registry record.
The safety analysis population consisted of participants who received at least a partial dose of study medication; the record gives this population as N=8058. It states that this population was used for all safety endpoints. The distinction between enrollment and the safety population matters: the registry identifies a safety-analysis population based on medication exposure, but does not explain all reasons for the difference between the listed enrollment and safety population.
Although the study aimed to assess smoking-cessation efficacy, the posted information in this record does not give efficacy results. It also does not report the randomization procedure, stratification factors, or details of treatment allocation beyond the randomized parallel-group description.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Participants were classified into 2 cohorts: participants without diagnosis of psychiatric disorder and participants with a stable diagnosis of psychiatric disorder confirmed by the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders (SCID) 4th edition conducted at screening.
Overall Study
| Stage | Varenicline | Bupropion | NRT Patch | Placebo |
|---|---|---|---|---|
| STARTED | 2037 | 2034 | 2038 | 2035 |
| Randomized and Treated | 2016 | 2006 | 2022 | 2014 |
| COMPLETED | 1598 | 1586 | 1557 | 1552 |
| NOT COMPLETED | 439 | 448 | 481 | 483 |
Reasons for not completing this period:
| Reason | Varenicline | Bupropion | NRT Patch | Placebo |
|---|---|---|---|---|
| Other reason | 41 | 30 | 36 | 33 |
| No longer meets eligibility criteria | 4 | 8 | 6 | 5 |
| Protocol Violation | 4 | 2 | 5 | 5 |
| Pregnancy | 1 | 0 | 0 | 1 |
| Insufficient clinical response | 4 | 4 | 14 | 13 |
| No longer willing to participate | 195 | 218 | 224 | 248 |
| Lost to Follow-up | 135 | 126 | 144 | 127 |
| Medication error | 0 | 1 | 0 | 1 |
| Adverse event (study drug) | 25 | 21 | 26 | 17 |
| Adverse event (study drug unrelated) | 9 | 7 | 9 | 9 |
| Death | 0 | 3 | 1 | 3 |
| Randomized but not treated | 21 | 28 | 16 | 21 |
Analysis population for the primary outcome, as defined in the registry: The safety dataset included all participants who had received at least one partial dose of study medication (N=8058) and was used to analyze all safety endpoints.
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
Population: The safety analysis population contained all treated participants i.e. who received at least one partial dose of study medication.
| Characteristic | Unit | Varenicline 1.0 mg BID | Bupropion | NRT Patch | Placebo | Total |
|---|---|---|---|---|---|---|
| Participants analysed | 2016 | 2006 | 2022 | 2014 | 8058 | |
| Age, Continuous | Years | 46.5 (SD 12.4) | 46.3 (SD 12.6) | 46.8 (SD 12.2) | 46.4 (SD 12.2) | 46.5 (SD 12.3) |
| Sex: Female, Male: Female | Participants | 1114 | 1116 | 1141 | 1138 | 4509 |
| Sex: Female, Male: Male | Participants | 902 | 890 | 881 | 876 | 3549 |
6. Primary Endpoint
The registry lists the primary outcome as Occurrence of Neuropsychiatric (NPS) Adverse Events (AE) - the Primary Study Endpoint, measured over Treatment emergent is first dose date to last dose date (up to 12 weeks) plus 30 days..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint measures the occurrence of at least one treatment-emergent neuropsychiatric adverse event meeting the stated event and severity criteria. Some listed events qualify at the severe level, while a broader set qualifies at the moderate or severe level. The endpoint is therefore a binary participant-level outcome: whether a participant experienced a qualifying event during the specified treatment-emergent window.
Combining clinically specified events into an endpoint can provide a planned way to assess a safety concern across treatment groups. The severity thresholds define which events count, and the time window defines when they count. These choices affect the interpretation: an event outside the window, or an event that does not meet the required severity threshold, would not meet this endpoint definition as written.
The endpoint is not a measure of every possible adverse event, and it does not describe the full clinical course of any event. The registry gives no information about event duration, recurrence, adjudication, or the number of participants meeting the primary endpoint in each treatment group. Those results are not reported in the registry record. The endpoint definition is available, but its treatment-specific frequency and comparative estimate cannot be evaluated from the reported primary-outcome information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record provides a detailed definition of the primary neuropsychiatric safety endpoint and identifies the population used for safety analyses. It does not report the primary endpoint’s treatment-group results or a statistical comparison. The record therefore supports describing what the trial intended to measure, but not whether the measured endpoint occurred more or less often in a particular group, or how precisely any difference was estimated.
The separately reported adverse-event summaries list serious adverse-event counts and counts for other adverse events by treatment group. These summaries are not a substitute for the primary endpoint. The primary endpoint uses a specified set of neuropsychiatric events and severity cutoffs; the registry’s serious-adverse-event summary does not establish that its events satisfy those endpoint criteria. Nor can broad counts for other events be treated as smoking-cessation outcomes or as the primary safety result.
The study included participants with and without a history of psychiatric disorders, and the listed secondary outcomes include results by psychiatric-history cohort. However, the registry record does not give the primary endpoint’s cohort-specific event results. Without those results, it is not possible to describe the endpoint separately by psychiatric history or assess whether the treatment comparisons differed between cohorts.
For a binary outcome, an event proportion describes the share of participants in a group who met the endpoint definition. A comparison between groups would need to be interpreted with its uncertainty, such as a confidence interval, and with attention to the analysis population and method. A confidence interval expresses a range of estimates compatible with the data and analysis assumptions; it does not guarantee that the true effect lies within that particular interval. No primary-endpoint proportions, effect estimate, confidence interval, or test result are reported in the registry record.
The trial is listed as completed, but completion alone does not supply the missing results. Likewise, the listed enrollment and safety population do not reveal the number of primary endpoint events. The statistical interpretation must remain limited to the data actually reported: there are descriptive adverse-event summaries, but no reported numerical primary endpoint comparison to interpret.
The record’s stated study aim includes smoking-cessation efficacy, but it does not provide an efficacy endpoint result in the registry record for this analysis. No conclusion about cessation outcomes follows from the safety summaries. More generally, an observed safety-event count would describe events during the defined observation period and in the analyzed population; it would not, by itself, establish causation or resolve risks outside that period.
9. Statistical Methods Explained
The registry describes the study as randomized, double-blind, parallel-group, multicenter, and controlled with active treatments and placebo. Those design features describe the intended comparison structure. Random allocation can help balance prognostic factors across groups on average, while masking can reduce some forms of bias in treatment delivery and outcome assessment. These are general explanations of design concepts; the record does not report the randomization method, masking procedures, or assessment safeguards in further detail.
What does the primary endpoint count?
The primary endpoint is a binary outcome at the participant level: a participant either experienced at least one qualifying treatment-emergent event or did not. The qualifying events and severity cutoffs are explicitly defined. This makes the endpoint more specific than a count of all reported adverse events, but it also means the result depends on how events were identified, classified, and assigned severity. Details of those procedures are not reported in the registry record.
A binary outcome can be summarized by the number of participants with an event and the number analyzed, or as a proportion. Comparing proportions across groups can be done using different statistical methods. The method matters, especially when event frequencies are low or groups differ in other ways. The statistical analysis method used for the primary endpoint is not reported in the registry record. No method should be inferred from the endpoint’s binary form alone.
How should uncertainty be understood?
A confidence interval describes uncertainty around an estimated quantity under the model and analysis used. Narrower intervals generally indicate more precise estimates, while wider intervals indicate greater uncertainty. Statistical significance and precision are related but not interchangeable: a result can be estimated imprecisely even when a test crosses a chosen threshold, and a small estimated difference can be precise. These are general concepts. The registry record does not report a confidence interval or test result for the primary endpoint, so neither precision nor statistical significance can be assessed for that outcome.
The posted planning assumptions describe an illustration using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They also state that the effect to detect is a specified fraction of the observed effect. Such assumptions define an illustrative calculation, not the trial’s observed result and not evidence that the trial had a particular probability of detecting an effect. The sample-size illustrations are planning aids, never observed power. The record does not report the trial’s own sample-size justification or enough detail to characterize its original design calculations.
Why can event rates be difficult to compare?
For a binary safety endpoint, the amount of information depends in part on how many qualifying events occur. Sparse events can make estimates unstable and intervals wide. When events are uncommon, even a modest number of additional or differently classified events can influence a group estimate. This is general statistical context, not a claim about the primary endpoint’s event frequency in this trial, which is not reported in the registry record.
For count outcomes, over-dispersion means the observed variability is greater than a simple model assumes. Models that fail to account for over-dispersion can understate uncertainty. That concept is not identified as relevant to this participant-level binary endpoint, and the record does not report a count model or a dispersion parameter. It should not be assumed that over-dispersion was present or that a particular correction was used.
What does the safety population represent?
The registry says safety analyses used participants who had received at least a partial dose of study medication, and gives N=8058 for this population. This is an exposure-based analysis population. It is not necessarily identical to every population used for efficacy or other analyses. The populations used for those analyses, and the handling of participants who did not receive study medication, are not reported in the registry record.
Using an exposed population is a recognizable approach for describing safety events, because it focuses on participants who took at least some study medication. It does not by itself resolve how events after discontinuation, missing observations, or differing exposure durations were handled. The primary endpoint definition specifies a treatment-emergent time window, but the record does not provide the detailed rules for missing data, follow-up, or analysis of participants with incomplete information.
What can be inferred from the posted adverse-event summaries?
The registry lists group-specific counts for serious adverse events and other adverse events, with the corresponding at-risk counts. These are descriptive data. They should be read according to their stated categories and not confused with the primary endpoint. No statistical comparison, adjusted estimate, or uncertainty interval for these summaries is reported in the registry record. The listed percentages for selected serious-event terms are descriptive as well; they do not provide a treatment comparison or establish attribution to a study drug.
The record lists 25 outcome measures and 25 analyses. Those counts indicate that multiple outcomes or analyses are part of the record, but do not describe the analysis hierarchy or how findings were selected for emphasis. The registry does not report a statistical analysis plan, model specifications, covariate adjustments, interim analyses, or multiplicity procedure. Those details cannot be reconstructed from the design label or endpoint description.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 25 outcome measures and 25 analyses, including secondary outcomes that assess components of the neuropsychiatric adverse-event endpoint, severe-only events, and a Hospital Anxiety and Depression Scale total score. When several outcomes, groups, or analyses are examined, the chance of a false-positive finding across all tests can increase. Common approaches to address this include prespecifying a hierarchy or adjusting the testing threshold. These are general statistical considerations, not methods that can be attributed to this trial.
The statistical analysis plan and any multiplicity procedure are not reported in the registry record. The record does not indicate which secondary outcomes were confirmatory, whether tests were adjusted, or how analyses were prioritized. Consequently, a result from an individual analysis, if reported elsewhere, could not be placed in a formal testing hierarchy from this record alone.
The record identifies the safety population as participants who received at least a partial dose of study medication, with N=8058, and says that it was used for all safety endpoints. It does not report the analysis populations for efficacy outcomes or other non-safety outcomes. Missing-data rules, exclusions after randomization, and methods for handling incomplete endpoint information are not reported in the registry record.
The primary endpoint’s treatment-emergent period is defined, but the record does not explain how incomplete follow-up or events with uncertain timing were handled. It also does not report imputation, sensitivity analyses, or procedures for evaluating robustness to missing data. These omissions limit assessment of whether the reported safety summaries, and any unreported comparisons, could be affected by missing information.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Varenicline 1.0 mg BID | 39 | 2016 | 1.9% |
| Bupropion | 48 | 2006 | 2.4% |
| NRT Patch | 45 | 2022 | 2.2% |
| Placebo | 41 | 2014 | 2.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Varenicline 1.0 mg BID | 1158 of 2016 |
| Bupropion | 1033 of 2006 |
| NRT Patch | 1003 of 2022 |
| Placebo | 884 of 2014 |
Most frequent serious adverse event terms
| Event term | Organ system | Varenicline 1.0 mg BID | Bupropion | NRT Patch | Placebo |
|---|---|---|---|---|---|
| Chest pain | General disorders | 1 of 2016 | 0 of 2006 | 4 of 2022 | 2 of 2014 |
| Suicidal ideation | Psychiatric disorders | 2 of 2016 | 1 of 2006 | 0 of 2022 | 3 of 2014 |
| Atrial fibrillation | Cardiac disorders | 0 of 2016 | 1 of 2006 | 4 of 2022 | 0 of 2014 |
| Suicide attempt | Psychiatric disorders | 0 of 2016 | 2 of 2006 | 1 of 2022 | 1 of 2014 |
| Non-cardiac chest pain | General disorders | 0 of 2016 | 2 of 2006 | 1 of 2022 | 1 of 2014 |
| Alcoholism | Psychiatric disorders | 0 of 2016 | 3 of 2006 | 1 of 2022 | 0 of 2014 |
| Myocardial infarction | Cardiac disorders | 1 of 2016 | 0 of 2006 | 1 of 2022 | 1 of 2014 |
| Bronchitis | Infections and infestations | 0 of 2016 | 1 of 2006 | 1 of 2022 | 1 of 2014 |
| Pneumonia | Infections and infestations | 1 of 2016 | 0 of 2006 | 2 of 2022 | 0 of 2014 |
| Prostate cancer | Neoplasms benign, malignant and unspecified (incl cysts and polyps) | 0 of 2016 | 1 of 2006 | 1 of 2022 | 1 of 2014 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Varenicline 1.0 mg BID | Bupropion | NRT Patch | Placebo |
|---|---|---|---|---|---|
| Nausea | Gastrointestinal disorders | 511 of 2016 | 201 of 2006 | 199 of 2022 | 137 of 2014 |
| Headache | Nervous system disorders | 245 of 2016 | 186 of 2006 | 233 of 2022 | 199 of 2014 |
| Insomnia | Psychiatric disorders | 189 of 2016 | 245 of 2006 | 195 of 2022 | 139 of 2014 |
| Abnormal dreams | Psychiatric disorders | 201 of 2016 | 131 of 2006 | 251 of 2022 | 92 of 2014 |
| Nasopharyngitis | Infections and infestations | 174 of 2016 | 156 of 2006 | 126 of 2022 | 135 of 2014 |
| Anxiety | Psychiatric disorders | 132 of 2016 | 169 of 2006 | 137 of 2022 | 120 of 2014 |
| Upper respiratory tract infection | Infections and infestations | 109 of 2016 | 104 of 2006 | 97 of 2022 | 115 of 2014 |
| Irritability | Psychiatric disorders | 82 of 2016 | 71 of 2006 | 108 of 2022 | 104 of 2014 |
| Fatigue | General disorders | 124 of 2016 | 57 of 2006 | 75 of 2022 | 83 of 2014 |
| Dry mouth | Gastrointestinal disorders | 66 of 2016 | 146 of 2006 | 59 of 2022 | 64 of 2014 |
Serious events with the highest arm-level rate: atrial fibrillation (0.2%), chest pain (0.2%), alcoholism (0.1%), suicidal ideation (0.1%), suicide attempt (0.1%).
The serious-adverse-event summary reports affected-participant counts and at-risk counts by group. Varenicline 1.0 mg BID lists 39 affected among 2016 at risk; Bupropion lists 48 among 2006; NRT Patch lists 45 among 2022; and Placebo lists 41 among 2014. The registry also lists counts for other adverse events: 1158 among 2016 for Varenicline 1.0 mg BID, 1033 among 2006 for Bupropion, 1003 among 2022 for NRT Patch, and 884 among 2014 for Placebo.
These are descriptive group summaries. They are not adjusted comparisons, and the record does not provide confidence intervals or statistical tests for them. The counts should not be interpreted as the primary neuropsychiatric endpoint: that endpoint has its own event list, severity criteria, and treatment-emergent window, while the serious-event summary is reported separately.
The registry identifies atrial fibrillation and chest pain at 0.2% each among the listed serious-event terms. Alcoholism, suicidal ideation, suicide attempt, and non-cardiac chest pain are listed at 0.1% each. These percentages are descriptive and do not establish that a treatment caused an event or indicate a between-group difference. Death counts are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a large randomized, double-blind study examined smoking-cessation treatments and neuropsychiatric safety in participants with and without a history of psychiatric disorders. It describes the intended treatments, the primary safety endpoint, its event window, and the population used for safety analyses. It also reports descriptive adverse-event summaries by treatment group.
Those details are useful for understanding the scope of the study, but they do not answer the primary comparative question. The registry record does not report the number or proportion of participants meeting the primary endpoint by group, nor an effect estimate, confidence interval, or test result. It is therefore not possible to determine from these data how often the endpoint occurred in each group or how precisely the groups differed.
The serious-adverse-event counts and selected event-term percentages should not be substituted for the primary endpoint result. They describe different reported categories and do not provide a randomized comparison adjusted for uncertainty. They also do not show whether an individual event was caused by treatment.
The stated study aim includes smoking-cessation efficacy, but efficacy results are not reported in the registry record. No conclusion about cessation outcomes can be drawn from the safety information. Similarly, the inclusion of participants with and without psychiatric history does not by itself establish whether treatment effects or safety outcomes were similar across those cohorts; the relevant primary endpoint results by cohort are not reported.
In general, trial findings apply most directly to the population, treatments, outcome definitions, and observation period actually studied. The registry identifies the participant groups and the safety-event window, but does not provide enough results to evaluate treatment effects or their precision. The record can describe what the trial set out to assess and some adverse-event counts, but it cannot support a conclusion about comparative efficacy or the primary safety endpoint.
13. Why This Trial Matters Statistically
This trial is statistically notable for addressing safety in participants with and without a history of psychiatric disorders while comparing active smoking-cessation treatments with placebo. Its randomized, double-blind, parallel-group design provides a structure for comparing groups, and the registry makes the primary endpoint’s event types and severity thresholds explicit. Clear outcome definitions are important because different event sets or thresholds can produce different safety summaries.
The cohort distinction is also important to interpretation. An overall estimate can conceal variation between populations, while separate cohort estimates can be less precise when events are limited. These are general considerations. The registry lists cohort-related secondary outcomes, but does not report the primary endpoint results by cohort, so the extent to which this issue affected the study’s findings cannot be assessed from this record.
The record also illustrates the difference between a trial’s intended question and the results available for statistical interpretation. Design information and adverse-event counts do not replace an endpoint-specific comparison with an uncertainty estimate. Without those primary results, readers cannot assess the size or precision of the treatment-group differences for the outcome that anchored the safety question.
Finally, the distinction between the listed enrollment and the defined safety population matters. The record specifies that safety analyses included participants who received at least a partial dose, but does not provide a full account of other analysis populations or missing-data handling. Clear reporting of populations, endpoint results, uncertainty, and analysis methods is necessary to judge how well statistical conclusions follow from the trial design.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The main limitation for interpretation is that the registry record does not report treatment-group results for the primary neuropsychiatric safety endpoint. It gives the endpoint definition and observation window, but not the group-specific event counts or proportions, a comparative estimate, uncertainty intervals, or a test result. This prevents assessment of the primary safety comparison’s size and precision.
Although the trial included participants with and without a history of psychiatric disorders, the primary endpoint results by cohort are not reported in the registry record. The listed secondary outcomes indicate that cohort-specific and component outcomes were considered, but their results are not included in the registry record for this analysis.
The record’s serious and other adverse-event summaries are descriptive and do not supply the missing primary endpoint comparison. Selected serious-event terms are listed with percentages, but no treatment attribution or comparative analysis is reported. The death entries are not reported in the registry record.
Further limitations are the lack of reported detail on randomization procedures, the statistical analysis plan, multiplicity, missing-data handling, and analysis populations outside safety. The available arm-description text is incomplete. The stated study aim includes smoking-cessation efficacy, but efficacy results are not reported in the registry record. These gaps restrict conclusions about both treatment comparisons and the robustness of any analyses.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study Evaluating The Safety And Efficacy Of Varenicline and Bupropion For Smoking Cessation In Subjects With And Without A History Of Psychiatric Disorders — NCT01456936.
- Registry record last updated 2016-06-10; status last verified 2016-05.
- Results first posted 2016-05-02.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry lists NCT01456936 as a completed phase 4 randomized, double-blind, parallel-group, multicenter study of varenicline, bupropion, nicotine replacement therapy patch, and placebo for smoking cessation. It enrolled 8144 participants, with a safety population of N=8058 defined by receipt of at least a partial dose. The study included participants with and without a history of psychiatric disorders.
The primary endpoint was the occurrence of specified treatment-emergent neuropsychiatric adverse events meeting event-specific severity criteria. Its window extended from first dose to last dose, up to 12 weeks, and through 30 days afterward. The registry record reports serious and other adverse-event counts by group, but does not report the primary endpoint’s group results or a comparative estimate. Efficacy results and several analysis details are also not reported in the registry record.