Nicotine Pharmacokinetic Profile and Safety of the Tobacco Heating System 2.2 Menthol (THS 2.2 Menthol).: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nicotine Pharmacokinetic Profile and Safety of the Tobacco Heating System 2.2 Menthol (THS 2.2 Menthol). (NCT01967706), a randomized na study. The primary outcome is Maximum Concentration (Cmax) of Nicotine Following Single Use of mTHS, mCC and NRT.

2. Clinical Question

The study asks how nicotine exposure after a single use of Tobacco Heating System 2.2 Menthol (mTHS) compares with exposure after a single use of a menthol conventional cigarette (mCC) or nicotine replacement therapy gum (NRT). The primary pharmacokinetic endpoint is maximum blood nicotine concentration, or Cmax. This is a measure of the highest observed concentration during the blood-sampling period and addresses the rate and amount of nicotine absorbed.

This is a question about short-term nicotine pharmacokinetics under the study conditions. It is not a comparison of long-term use, smoking behavior, disease outcomes, or the health effects of continued exposure. The registry record does not report evidence that would answer those broader questions.

3. Trial Design

This was a randomized, single-center, open-label, controlled crossover study. The registry lists enrollment of 73 and status as completed. The phase is listed as NA. The study start is recorded as 2013-08 and primary completion as 2013-11.

In a crossover design, participants receive more than one study condition in different periods, so comparisons can be made within the same participant. Here, the sequences included mTHS followed by mCC, mCC followed by mTHS, mTHS followed by NRT, and NRT followed by mTHS. The arm descriptions specify a wash-out period before the first intervention and another wash-out between the first and second interventions. Each intervention was a single product use or, for NRT, a single administration.

The open-label design means masking was absent. The registry record does not report whether outcome assessors or laboratory personnel were masked. A crossover structure can reduce the influence of stable differences between participants on a treatment comparison, but it does not by itself remove possible effects of treatment order, period, or carryover. The record does not report the statistical handling of those effects.

The PK population was not simply every person enrolled. It consisted of randomized subjects who completed at least one of the single-use days and for whom at least one PK parameter could be derived. Subjects whose major protocol deviations affected evaluability were excluded from the PK populations. The registry record does not provide a complete accounting of the number included in each PK comparison or explain how incomplete sampling was handled.

The intervention sequences support comparisons involving all three products, but the posted inferential result is limited to the mTHS and mCC groups. No inferential comparison between mTHS and NRT is reported in the registry record.

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: Enrolled population = 73 subjects: 11 exposed to mTHS and NRT at Admission but not randomized and 62 randomized as described below: * Sequence "mTHS then mCC": 22 subjects * Sequence "mCC then mTHS": 22 subjects * Sequence "mTHS then NRT": 9 subjects * Sequence "NRT then mTHS": 9 subjects

Washout Period of 1 Day (Day 0)

First Intervention (Day 1)

Reasons for not completing this period:

Washout Period of 1 Day (Day 2)

Second Intervention (Day 3)

Analysis population for the primary outcome, as defined in the registry: PK populations consisted of all the randomized subjects who completed at least 1 of the single use days (Days 1 or 3), and for whom at least 1 PK parameter could be derived. Subjects with major protocol deviations that impacted the evaluability of the results were excluded from the PK populations.

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: PK population: all randomized subjects who completed at least 1 of the single-use days, with at least 1 derived PK parameter. Subjects with major protocol deviations impacting the evaluation of the results were excluded. 62 randomized subjects : 44 in Group 1, 18 in Group 2. 61 completers: 43 in Group 1 (1 withdrawn subject), 18 in Group 2.

6. Primary Endpoint

The registry lists the primary outcome as Maximum Concentration (Cmax) of Nicotine Following Single Use of mTHS, mCC and NRT, measured over Blood taken 15 minutes prior to T0, 2, 4, 6, 8, 10, 15, 30, 45 minutes, 1, 2, 4, 6, 9, 12, and 24 hours after T0.

The primary endpoint is maximum concentration of nicotine, Cmax, measured in ng/mL after single use of mTHS, mCC, and NRT. It is a continuous pharmacokinetic measure. The registry reports geometric least-squares means and 95% confidence intervals, rather than raw individual concentrations or an arithmetic mean.

Blood sampling began before product use and continued at multiple time points through 24 hours after T0, the start of single product use. Cmax captures the highest concentration observed across that sampling period. It is useful for describing the peak level reached, while the sampling schedule provides the observations from which the peak is identified. Cmax does not, by itself, describe the full concentration-time profile or total exposure over time.

The endpoint addresses the stated objective of comparing the rate and amount of nicotine absorbed after a single use. It does not measure repeated-use patterns, sustained exposure, dependence, clinical events, or long-term health outcomes. Nor does a peak concentration alone establish the experience or consequences of use outside the study conditions.

The PK population definition matters to interpretation: the estimates pertain to randomized subjects with at least one completed single-use day and at least one derivable PK parameter, after excluding major protocol deviations that affected evaluability. The registry record does not report individual-level concentration data or additional endpoint summaries such as time to peak concentration.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the geometric least-squares mean describe?

A least-squares mean is a model-based estimate of a group mean. It can account for terms included in the statistical model, so it need not be identical to a simple average of the observed measurements. The registry describes the reported Cmax estimates as geometric least-squares means. A geometric mean is suited to positive measurements that may be skewed, because it summarizes values on a multiplicative rather than additive scale. It is still a group-level summary and does not show the spread of every participant's result.

The registry identifies ANOVA as the method for the mTHS and mCC comparison and describes its result as a geometric least-squares mean ratio. ANOVA is a general framework for comparing group means while accounting for model terms. The record does not give the model specification, including which terms were included or how the crossover sequence and periods were handled. Those details are important for understanding precisely what the reported model adjusted for.

How should the confidence interval be read?

A confidence interval expresses uncertainty around an estimated quantity under the assumptions of the statistical procedure. A narrower interval generally indicates greater precision, while a wider interval indicates more uncertainty. It is not a range containing most individual observations, and it does not describe the full distribution of Cmax measurements. The reported intervals accompany the geometric least-squares means and the ratio, but the registry does not provide the underlying participant-level data needed to examine the distribution directly.

For the reported ratio, the confidence interval describes uncertainty in the model-based comparison. The point estimate alone does not convey that uncertainty. No p-value accompanies the reported ANOVA result, so the registry does not provide that additional summary of the comparison. A p-value, where reported, would address compatibility with a specified null hypothesis under model assumptions; it would not measure effect size or the probability that a hypothesis is true.

Why does the crossover structure matter?

In a crossover study, each participant can contribute measurements under different treatments. This can make within-participant comparisons informative because stable participant characteristics are shared across treatment periods. However, treatment order, period effects, and residual effects from a prior treatment can affect interpretation. Randomized sequence order can help address systematic ordering, but the design alone does not show whether those effects were tested or modeled. Their handling is not reported in the registry record.

The stated wash-out periods separate product-use periods in the described sequences. The record does not report the rationale for the wash-out duration or evidence about whether it was sufficient for the pharmacokinetic comparison. The analysis population also required completion of at least one single-use day and at least one derivable PK parameter, with exclusions for major protocol deviations affecting evaluability. These criteria define which observations contributed, but further details about incomplete profiles and missing time points are not reported.

What do the planning illustrations represent?

Planning illustrations based on the observed effect are not observed power and are not evidence that the study was designed around those assumptions. The described planning framework uses a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect to detect expressed as a stated fraction of the observed effect. Those are planning assumptions, not features that can be attributed to the trial's original design unless the registry says so. The registry record does not report the trial's sample-size justification.

Power is a prospective design quantity: it concerns the probability that a specified analysis would detect a specified effect under stated assumptions. It is not a measure of how likely the observed result is to be true. Recalculations from posted summary statistics, when labeled as recalculated, are unadjusted calculations and can differ from the trial's model-based analysis. No extra effect estimate or planning result should be inferred from the reported summaries alone.

Why does over-dispersion matter in general?

For outcomes that are counts, a simple model may assume that variability follows a particular relationship to the mean. Over-dispersion means the observed variability is greater than that assumption allows. If it is ignored, standard errors and confidence intervals can be misleading. This is a general statistical issue and does not describe the primary Cmax endpoint here, which is continuous. The registry record does not report a count-based primary analysis.

Overall, the posted summaries allow the reader to see geometric least-squares mean estimates, their confidence intervals, and one reported ANOVA ratio. The missing model specification, participant-level data, and additional comparison results limit independent reconstruction and fuller assessment of the analysis.

10. Analyses Reported by the Sponsor

The registry reports an ANOVA analysis comparing mTHS and mCC, with a geometric least-squares mean ratio of 88.47 and a 95% confidence interval from 68.64 to 114.03. This is the sponsor's reported model-based comparison in the record. It is distinct in form from the separate group-specific geometric least-squares mean estimates.

The record does not give a p-value for the ANOVA result or enough model detail to reproduce it. It also does not report a recalculated comparison alongside the sponsor analysis. Consequently, there is no posted recalculated estimate to set against the sponsor's result. The arm summaries alone do not specify the model used for the reported ratio, and a reconstruction from summary statistics would not necessarily reproduce an analysis that accounts for the crossover design.

The registry record does not flag a discrepancy between the sponsor analysis and a recalculation. The reported analysis should therefore be read as the registry's stated inferential result, with its uncertainty and documentation limits. It should not be supplemented with an independently inferred p-value or an unreported comparison with NRT.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures and two analyses, but reports no secondary outcome results. The available material identifies Cmax as the primary endpoint and includes one reported inferential comparison, between mTHS and mCC. A corresponding inferential result for mTHS versus NRT is not reported in the registry record.

Multiplicity arises when multiple hypotheses or outcomes are examined. Without a reported analysis plan, it is not possible to determine whether the reported comparison was the only planned primary contrast, whether other comparisons were prespecified, or whether any adjustment for multiple testing was planned or used. The record does not report a multiplicity adjustment. That absence should not be interpreted as proof that no adjustment was made outside the information recorded.

The PK population definition is stated: randomized subjects had to complete at least one single-use day and have at least one derivable PK parameter, and subjects with major protocol deviations affecting evaluability were excluded. The registry does not report the number excluded for each reason or a complete flow from enrollment through each analysis population. It also does not describe how missing blood samples, incomplete concentration-time profiles, or unavailable PK parameters were handled.

The record does not report an intention-to-treat analysis, an imputation method, sensitivity analyses for missing data, or a comparison of included and excluded subjects. The eligibility rule for the PK analysis should therefore be treated as the available description, not as a complete account of missing-data handling. The registry also does not report an interim analysis plan, a stopping rule, or the trial's sample-size justification.

These omissions limit assessment of the prespecification and robustness of the findings. They do not establish that the analyses were inappropriate; they mean the registry record does not document enough detail to evaluate those aspects.

12. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety record reports no serious adverse events among the 44 participants at risk in Group 1, and none among the 18 participants at risk in Group 2. It also reports no serious adverse events among the 11 enrolled but not randomized participants. These are the recorded serious-event counts and their corresponding at-risk denominators.

For other adverse events, the record reports none among the 44 participants at risk in Group 1, one among the 18 at risk in Group 2, and none among the 11 enrolled but not randomized participants. The record does not identify a top serious adverse-event term. A deaths value is not reported in the registry record; a missing value should not be read as a recorded count of zero.

These safety figures are descriptive. They do not establish the absence of risk, especially in a study of this size and with single-use exposure. The registry record does not provide detailed event descriptions, timing, severity, relatedness assessments, or confidence intervals for the event counts. Nor does it provide a comparative statistical analysis of safety between products.

The groups refer to the reported safety categories and should not be combined or treated as equivalent to the PK analysis populations. The safety counts are useful for describing what the registry recorded, but they do not support broad conclusions about uncommon events or safety with repeated use.

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

The posted results describe peak nicotine concentration after single use of mTHS, mCC, and NRT in the study's PK populations. They include geometric least-squares mean estimates with 95% confidence intervals and a reported ANOVA ratio for mTHS compared with mCC. The results provide a short-term pharmacokinetic description under the study conditions.

They do not establish what happens with repeated or long-term use. Cmax is a peak concentration measure, not a complete account of exposure over time, and it is not a clinical outcome. The record does not report long-term health outcomes, changes in smoking behavior, or evidence about disease risk. The product's description as a candidate Modified Risk Tobacco Product is not itself evidence of reduced risk.

The reported comparison should not be extended to NRT: although NRT estimates are posted, an inferential comparison with mTHS is not reported. Nor should the results be generalized beyond the smoking, healthy subjects described in the study without evidence about other populations or settings. The single-center, open-label design and the eligibility rules for the PK population are relevant to the scope of interpretation.

The intervals communicate uncertainty in the estimated quantities, while the absence of a reported p-value and incomplete model details limit further statistical interpretation. The registry also does not document multiplicity handling, missing-data procedures, or the full analysis plan. These gaps make it important to distinguish the values that are posted from broader conclusions that the record cannot support.

In short, the record offers estimates of Cmax and one model-based mTHS-to-mCC comparison after single use. It does not answer questions about sustained exposure, repeated use, comparative clinical benefit, or long-term safety.

14. Why This Trial Matters Statistically

This study is statistically interesting because a randomized crossover design can compare product conditions within participants. Such designs can be efficient for pharmacokinetic outcomes when measurements under different conditions are available for the same participants. The sequence descriptions show that treatment order varied, while the wash-out periods separated single-use interventions.

The results also illustrate why an endpoint estimate and a comparative analysis should be kept distinct. The group-specific geometric least-squares means describe estimated Cmax levels, whereas the ANOVA ratio summarizes a model-based comparison. Confidence intervals add information about precision that a point estimate alone does not convey. The registry's limited model description means readers cannot determine exactly how the crossover features entered that comparison.

Another important statistical distinction is between a posted result and an unreported contrast. The registry includes estimates for NRT, but the reported ANOVA comparison is between mTHS and mCC. Similar-looking estimates do not substitute for a formal comparison, and the record does not report one for mTHS versus NRT.

The study also demonstrates the boundary between pharmacokinetic measures and clinical outcomes. Cmax is relevant to the profile of nicotine absorption, but it is not itself a measure of long-term health or behavioral effects. Safety counts from a single-use study likewise offer descriptive information, not a complete account of uncommon or longer-term events.

Finally, the registry's stated PK population and absent details on missing data, multiplicity, and model specification show why transparency about analysis decisions matters. These features determine how confidently readers can assess the reported comparison and how far it can be generalized.

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 registry record describes a single-center, open-label study of single-use product exposures. Masking is listed as none, and the record does not report masking of laboratory or outcome assessment. The study therefore does not address longer-term product use or outcomes beyond the stated pharmacokinetic and safety measures.

The main inferential result reported is the ANOVA comparison between mTHS and mCC. Although group-specific NRT estimates are included, an inferential mTHS-to-NRT comparison is not reported. The model specification, treatment of period and sequence, and handling of possible carryover are not reported in the registry record. This limits independent assessment of the crossover analysis.

The PK population excludes subjects with major protocol deviations that affected evaluability and requires at least one completed single-use day and at least one derivable PK parameter. The registry does not report how many subjects were excluded for each reason, how incomplete sampling was handled, or whether sensitivity analyses were performed. The number enrolled should not be treated as the number contributing to each endpoint estimate.

The record does not report a sample-size justification, a complete statistical analysis plan, multiplicity procedures, an interim analysis plan, or a p-value for the reported ANOVA result. It also does not provide individual-level data or detailed safety-event descriptions. The safety record's missing deaths value is not equivalent to a reported zero.

These limitations concern what can be assessed from the registry record. They do not establish that unreported procedures were not conducted; they mean those procedures cannot be evaluated from the recorded information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Nicotine Pharmacokinetic Profile and Safety of the Tobacco Heating System 2.2 Menthol (THS 2.2 Menthol). — NCT01967706.
• Registry record last updated 2020-03-18; status last verified 2020-03.
• Results first posted 2016-02-02.
• 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.

19. Record Summary

NCT01967706 is a completed, randomized, open-label, single-center crossover study of single-use mTHS, mCC, and NRT in smoking, healthy subjects. Enrollment was 73. The registry reports geometric least-squares mean Cmax estimates with 95% confidence intervals for the product groups and an ANOVA-based mTHS-to-mCC ratio of 88.47, with a 95% confidence interval from 68.64 to 114.03.

The record also reports descriptive adverse-event counts. It does not report a corresponding inferential comparison between mTHS and NRT, a p-value for the posted ANOVA result, full model details, or complete missing-data and multiplicity procedures. The findings concern single-use nicotine pharmacokinetics and the safety counts recorded under the study conditions; they do not establish long-term effects.