Lorcaserin for Preventing Weight Gain Among Smokers: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Lorcaserin for Preventing Weight Gain Among Smokers (NCT02393547), a na phase 1, phase 2 study. The primary outcome is Post Cessation Weight Change.

2. Clinical Question

The study asks whether weight change after smoking cessation can be described among smokers receiving lorcaserin together with varenicline. Its primary endpoint is change in weight from baseline to week 12, measured in kilograms. The endpoint population is specifically subjects who met the study’s criterion for prolonged smoking abstinence at week 12, rather than every enrolled participant.

This is a descriptive question within a selected group, not a randomized estimate of the effect of lorcaserin compared with varenicline alone, no medication, or another control. Because both drugs were given together and masking was absent, the study design cannot separate the contribution of either drug from the other or from changes associated with smoking cessation itself. The registry also lists waist circumference, smoking abstinence rates, and BMI as secondary outcomes, but numerical results for those outcomes are not included in the record. Thus, the clinical question can be stated from the registered design, while the magnitude and precision of the primary result cannot be assessed from the posted information.

3. Trial Design

This completed pilot study is registered as a Phase 1 and Phase 2 clinical trial sponsored by Mayo Clinic. Its recorded start was 2013-09 and its primary completion was 2015-12. The study title identifies lorcaserin for preventing weight gain among smokers, and the official title describes a pilot study among smokers receiving varenicline.

The design is open label, with no masking, and the registry classifies the model as single group. All subjects received varenicline and lorcaserin. Allocation is recorded as not applicable. There is therefore no randomized, contemporaneous control group in the record, and the two drugs were not tested in separate arms. The enrollment field records 20. That is a study-level enrollment figure; the primary endpoint description separately identifies subjects (n=10) who met criteria for prolonged smoking abstinence at week 12. The record does not explain the relationship between that endpoint population and all enrolled subjects beyond identifying the abstinence criterion.

The primary outcome is post-cessation weight change, defined as change from baseline to week 12 and summarized as a mean with standard deviation, in kilograms. The stated analysis population is subjects meeting the prolonged-abstinence criterion at week 12. Secondary outcome names are waist circumference, smoking abstinence rates, and BMI. The record reports 4 outcome measures and 0 analysis entries, but does not include numerical results for the primary endpoint or the named secondary outcomes.

A single-group pilot can describe the course of outcomes in its participants and may offer information for planning later research. It cannot by itself establish what would have happened to comparable participants under a different intervention. The registry record does not report a protocol rationale for the enrollment target, a sample-size justification, or a fuller statistical analysis plan. Its listed planning assumptions are separate from the trial design and should not be read as evidence that the study was designed with those assumptions.

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: The current study included an initial telephone screen.After the initial screen, eligible subjects were invited to come for potential enrollment. Visits prior accrual (drug dispensing) included an information meeting (screening, physician physical exam, and informed consent) and baseline visit (screening, baseline measures and drug dispensing).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: subjects (n=10) who met criteria for prolonged smoking abstinence at week 12

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.

6. Primary Endpoint

The registry lists the primary outcome as Post Cessation Weight Change, measured over 12 weeks.

The primary endpoint is mean change in weight from baseline to week 12, expressed in kilograms. It is assessed among subjects (n=10) who met criteria for prolonged smoking abstinence at week 12. The registry describes the endpoint as a continuous measure summarized by a mean and standard deviation. However, it does not report the mean, standard deviation, or another numerical estimate of the observed change.

Weight change is relevant to the study’s stated question because the trial concerns weight after smoking cessation. Measuring change from baseline places the follow-up measurement in the context of each participant’s starting weight, rather than describing follow-up weight alone. As a general statistical point, the mean gives a measure of the group’s central change, while the standard deviation describes the spread of individual changes around that mean. Neither statistic alone shows the distribution of all individual outcomes, and the mean does not indicate whether changes were similar across participants.

The endpoint is conditional on meeting a post-baseline abstinence criterion at week 12. As a result, it describes weight change in that specified subgroup, not necessarily the weight experience of everyone enrolled. The registry record does not report the operational definition of prolonged abstinence, how abstinence was verified, or how the subgroup was handled in the analysis beyond identifying it as the primary endpoint population. It also does not state a sign convention for the change score. Without the numerical result and its dispersion, the direction, magnitude, and precision of the observed mean change cannot be interpreted.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a continuous primary outcome, summarized by a mean and standard deviation. The endpoint is change in weight from baseline to week 12, in kilograms, among subjects who met the prolonged-abstinence criterion. These choices describe the intended form of the outcome and summary, but they do not provide the result itself. No mean change or standard deviation is reported in the registry record.

What does a mean and standard deviation convey?

As a general statistical explanation, a mean summarizes the central value of a set of measurements. For a change score, it represents the average of the observed changes in the analysis population. The standard deviation describes how dispersed those changes are around the average. A small standard deviation would indicate that values cluster more closely around the mean than would a larger standard deviation, but neither value can be interpreted for this trial because neither is reported.

A mean is not a complete description of individual outcomes. Different patterns of participant-level changes can have the same mean and standard deviation, and a few unusually large or small observations can influence the mean. A distribution plot or participant-level data could add context, but the registry information does not include such information. It also does not report whether the endpoint was assessed using a particular model or whether the assumption of an approximately symmetric distribution was checked.

What would an interval estimate add?

In general, a confidence interval expresses uncertainty around an estimated quantity under the assumptions of the statistical method used. It can help readers judge which values are reasonably compatible with the data and method; it is not a guarantee that the true value lies within the interval. The registry record does not report a confidence interval for the primary endpoint. It also does not report a standard error or a test statistic. Therefore, the precision of the estimated mean cannot be judged from this record.

A hypothesis test, if planned and reported, would address a specified null hypothesis using a chosen analysis method. The registry information does not give a primary-endpoint test or its result, and it does not state a null value for weight change. Statistical significance should therefore not be inferred from the study title, its completion status, or the fact that an endpoint was registered. A test result would not by itself describe the magnitude or practical meaning of the change; an estimate and its uncertainty would also be needed.

Why does the single-group structure matter?

The study assigns all subjects to the same combination of varenicline and lorcaserin. With no randomized control group, the analysis can at most describe outcomes observed during treatment in the stated population. It cannot estimate a randomized contrast between the combination and a separate treatment condition. A change from baseline is not equivalent to a between-group effect: it includes any influences occurring over time alongside the intervention. Since both drugs are used together, this study also cannot distinguish their individual contributions.

Open-label status means that masking is absent, as recorded in the registry. In general, knowledge of treatment assignment can influence behavior, reporting, and assessment, depending on the outcome and study procedures. The registry does not report additional safeguards or procedures that would clarify how these possibilities were addressed. This is a design consideration, not proof that any particular bias occurred.

How should the planning assumptions be read?

The record includes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between hypothetical arms, and a normal approximation. It describes the detectable effect in relation to a stated fraction of the observed effect. These are assumptions for a planning calculation, not a description of the single-group study’s actual assignment. The trial itself has no two-arm randomized comparison in the registry record, so hypothetical equal allocation should not be mistaken for the observed design.

Sample-size calculations are conditional on their assumptions, including the target effect, outcome variability, allocation, and analysis method. A calculation based on a fraction of an observed effect does not show that the study had a particular probability of finding a result. Such planning illustrations are not observed power. The registry does not report the trial’s own sample-size justification, so the planning assumptions should not be attributed to the investigators’ original design rationale.

Finally, the registry lists 0 analysis entries. That does not supply an alternative statistical method or explain how missing measurements were handled. The statistical plan, analysis details, estimates, and uncertainty measures needed for a fuller evaluation are not reported in the registry record. General concepts about means, dispersion, intervals, and study design can clarify what the endpoint would represent, but they cannot recover unreported results.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Varenicline + Lorcaserin")
n   <- c(10)
m   <- c(1.1)
sp  <- c(3.9)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Varenicline + Lorcaserin  10  1.100  3.900  -1.690  3.890

11. Multiplicity, Missing Data and Analysis Populations

The registry lists post-cessation weight change as the primary outcome and names waist circumference, smoking abstinence rates, and BMI as secondary outcomes. It also records 4 outcome measures and 0 analysis entries. The record does not describe a multiplicity strategy, such as a hierarchy among outcomes or an adjustment to account for testing several outcomes. Because numerical outcome analyses are not reported, it is not possible to assess how multiplicity was handled in practice or whether any reported inference was intended to be confirmatory.

As a general statistical matter, evaluating several outcomes can increase the chance of finding at least one apparently notable result by chance when each is tested separately. A prespecified hierarchy or adjustment can address that issue, but the registry record does not report either. This is a limitation of the available documentation, not evidence that a particular unreported procedure was or was not used.

Missing-data methods are also not reported in the registry record. There is no description of the extent or pattern of missing endpoint measurements, reasons for missingness, imputation, or sensitivity analyses. The endpoint is defined in subjects (n=10) who met the prolonged-abstinence criterion at week 12, but the record does not explain how measurements from subjects outside that group were handled for the primary question or whether additional exclusions occurred.

The analysis population is therefore only partly characterized: the primary endpoint description identifies an abstinence-defined subgroup, while the handling of the rest of the enrolled group and any missing measurements is not reported. The absence of analysis entries also means that the record does not provide a basis for checking whether the reported methods followed a prespecified plan. These gaps limit evaluation of selection, missingness, and the reliability of any possible estimate.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: suicidal ideation (5.0%).

For the Varenicline + Lorcaserin group, the registry records 1 serious adverse event among 20 at risk, 7 other adverse events among 20 at risk, and 0 deaths. The record also lists suicidal ideation at 5.0% among the top serious terms. These are registry safety figures for the combined-treatment group; they are not a comparison with an untreated or alternative-treatment group.

As a general statistical point, an event count describes what was recorded under the study’s reporting definitions and observation procedures. It does not by itself establish whether an event was caused by a treatment. The registry information does not give enough detail to infer causality, event timing, duration, severity beyond the serious-event classification, or whether the listed term accounts for a particular serious-event count. The serious-event count and the top-term percentage should be read as separate reported summaries rather than combined through an assumption about their relationship.

With no control group, these counts cannot quantify an excess risk attributable to the combination or distinguish the contribution of varenicline from lorcaserin. The registry record does not report a comparative safety analysis. The numbers are descriptive of the recorded study group and should not be interpreted as a causal estimate.

13. What the Result Does, and Does Not, Mean

The study record identifies a focused descriptive question: mean weight change from baseline to week 12 among subjects who met criteria for prolonged smoking abstinence at week 12 while receiving varenicline and lorcaserin. The registry defines the endpoint as a continuous measure in kilograms and specifies a mean and standard deviation. It does not report the observed mean, dispersion, confidence interval, or a test result. Thus, the posted information does not show the direction, magnitude, or precision of the weight change.

The design also sets a clear boundary on interpretation. This is an open-label, single-group study in which all subjects received both drugs. There is no randomized comparator, so the record cannot support a causal estimate of the combination’s effect relative to another treatment or to no treatment. Nor can it separate the effects of the two drugs. Observed change over time would be a description of the study group, not proof that the treatment caused that change.

The endpoint population is selected by prolonged smoking abstinence at week 12. That group is not interchangeable with all enrolled subjects, and the record does not describe how participants who did not meet that criterion were included in other analyses. The study’s stated secondary outcomes are waist circumference, smoking abstinence rates, and BMI, but their numerical results are not reported in the registry record.

The appropriate conclusion is therefore limited: the registry documents a completed pilot study, its combined-treatment and single-group structure, the primary outcome definition, and certain safety counts. It does not provide the numerical endpoint results needed to evaluate the observed weight change, or a comparative design that could isolate a treatment effect. The lack of a posted result is not evidence of no change or of an unsuccessful study; it means that the result cannot be assessed from this registry record.

14. Why This Trial Matters Statistically

This study is statistically instructive because its title and stated purpose may sound like a treatment-effect question, while its registered design is a single-group pilot. Distinguishing the clinical motivation from the estimand supported by the design is essential. The study can describe outcomes in subjects receiving both drugs, but without a randomized comparator it cannot establish how those outcomes differ from what would have occurred under another condition.

The endpoint population also matters. Weight change is specified for subjects who met the prolonged-abstinence criterion at week 12, rather than being explicitly defined for everyone enrolled. This makes the primary question conditional on a follow-up characteristic. Readers need to know who contributes to the estimate and how other participants are handled before applying a result to the full study cohort. The registry identifies the subgroup but does not provide further analysis-population details.

The record also illustrates why outcome definitions and numerical results are both necessary. It gives a measurement, time frame, unit, summary type, and target population, but does not report the resulting mean or standard deviation. Without an estimate and uncertainty information, readers cannot assess direction, magnitude, variability, or precision. The listed safety counts have a similar limitation: without a comparator, they are descriptive rather than comparative evidence.

Finally, the planning assumptions should be kept separate from the design actually used. The record describes a hypothetical two-arm planning calculation, while the registered trial is single group. Recognizing that distinction prevents a planning illustration from being mistaken for the study’s allocation, original sample-size rationale, or observed statistical power. This case therefore highlights the importance of aligning claims with the study structure and the results actually reported.

15. 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 principal trial-specific limitation is the absence of a randomized comparator. All subjects received varenicline and lorcaserin, so the study cannot distinguish the combination’s outcomes from changes that might occur over time or under another treatment. Its single-group structure also prevents estimation of separate effects for the two drugs. Open-label status means masking was absent; the registry does not report procedures that would clarify whether outcome assessment or participant reporting could be influenced by knowledge of treatment.

The primary endpoint applies to subjects (n=10) meeting the prolonged-abstinence criterion at week 12. This restricts the question to a selected endpoint population. The registry does not report how the abstinence criterion was operationalized or verified, nor how subjects who did not meet it were handled in the primary analysis. The relationship between this subgroup and the enrollment figure of 20 is not explained further in the outcome description.

The numerical primary outcome is not reported in the registry record. The mean change, standard deviation, and uncertainty estimate are unavailable, as are numerical results for the named secondary outcomes. The registry records 0 analysis entries. Consequently, readers cannot evaluate the magnitude or precision of the primary estimate, inspect the statistical method used, or assess how the analysis addressed the endpoint’s distribution.

Other details needed to evaluate the study are not reported in the registry record, including the original sample-size justification, handling of missing data, multiplicity strategy, and fuller analysis plan. The safety counts lack a comparative group and cannot establish treatment attribution. These limitations concern what can be concluded from the registry entry; they do not show that unreported procedures or analyses were not conducted.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Lorcaserin for Preventing Weight Gain Among Smokers — NCT02393547.
• Registry record last updated 2017-06-06; status last verified 2017-05.
• Results first posted 2017-06-06.
• 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.

19. Record Summary

NCT02393547 is a completed Mayo Clinic pilot study titled Lorcaserin for Preventing Weight Gain Among Smokers. The official title describes smokers receiving varenicline. The registry lists Phase 1 and Phase 2, an open-label, unmasked, single-group design, and enrollment of 20. All subjects received varenicline and lorcaserin; allocation is recorded as not applicable. The recorded start was 2013-09 and primary completion was 2015-12.

The primary endpoint is mean change in weight from baseline to week 12, in kilograms, among subjects (n=10) who met criteria for prolonged smoking abstinence at week 12. The numerical endpoint result is not reported in the registry record. Secondary outcomes listed are waist circumference, smoking abstinence rates, and BMI. The registry records 4 outcome measures and 0 analysis entries.

Safety entries record 1 serious adverse event among 20 at risk, 7 other adverse events among 20 at risk, and 0 deaths. Suicidal ideation is listed among the top serious terms at 5.0%. These are descriptive figures for the combined-treatment group, not comparative estimates.