Botulinum Toxin A for Herpes Labialis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Botulinum Toxin A for Herpes Labialis (NCT01225341), a randomized na study. The primary outcome is Measurement of Recurrence and Duration of Herpes Labialis Lesions.

2. Clinical Question

3. Trial Design

The registry describes a randomized, double-blind, placebo-controlled crossover study, with onabotulinumtoxinA and bacteriostatic normal saline as the interventions. In a crossover design, participants are assigned to a sequence of treatments and may receive each treatment at different times. The listed sequences are onabotulinumtoxinA followed by saline, and saline followed by onabotulnimtoxinA. The registry entry does not explain the randomization procedure or how treatment periods and the switch between treatments were implemented.

The arm descriptions specify injections every 3 months for a period of 12 months, followed by the other injection at the 12 month visit. The record does not report whether there was a washout period, how long any treatment effect was expected to persist, or how outcomes from each treatment period were distinguished. Those details matter for interpreting a crossover comparison, because effects from an earlier period can potentially continue into a later period. They cannot be assumed for this study from the available description.

Double masking indicates that the registry classified the study as double-blind, but it does not identify which roles were masked or describe how masking was maintained. The registry lists enrollment as 20. It does not report how many participants were randomized, received each intervention, completed follow-up, or contributed data to an analysis. Study start is recorded as 2010-08 and primary completion as 2012-05. The status is TERMINATED.

The primary outcome was intended to measure recurrence and lesion duration over 12 months. Secondary outcomes listed in the record were lesion size, pain assessment, and symptom evaluation. Although the record lists four outcome measures, it contains no outcome data. The study team reported that the study was terminated, access to study data was no longer available, and the data had been destroyed after efforts to locate remaining data were unsuccessful. The registry record therefore does not support an assessment of the study’s comparative outcomes.

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 study was terminated and the PI/study team no longer has access to study data as it was destroyed. Efforts were exhausted to locate any remaining data, but were unsuccessful. No study data are available to report

Overall Study

Analysis population for the primary outcome, as defined in the registry: The study was terminated and the PI/study team no longer has access to study data as it was destroyed. Efforts were exhausted to locate any remaining data, but were unsuccessful. No study data are available to report

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 study was terminated and the PI/study team no longer has access to study data as it was destroyed. Efforts were exhausted to locate any remaining data, but were unsuccessful. No study data are available to report

6. Primary Endpoint

The registry lists the primary outcome as Measurement of Recurrence and Duration of Herpes Labialis Lesions, measured over 12 months.

The primary endpoint was titled “Measurement of Recurrence and Duration of Herpes Labialis Lesions.” Its description refers to days between the last injection and outbreak onset, and days between onset and recurrence, with a 12 months timeframe. These measures concern the timing of outbreaks and recurrence after an injection, rather than a single measure of lesion size or symptom intensity. The registry does not specify the unit field, a statistical parameter, or a dispersion measure for this outcome.

As a general statistical rationale, timing measures can describe how long it takes for an event to occur or how long an interval lasts. They may help characterize recurrence patterns in a way that a simple event count cannot. In a treatment comparison, the interpretation depends on a clear definition of the event, the start of follow-up, and how observations are handled when the event is not observed. Those operational details are not reported in the registry record. The phrasing also references both outbreak onset and recurrence, but does not explain how these were combined or whether they were analyzed as separate outcome components.

No observed endpoint values, group summaries, effect estimates, or uncertainty intervals are available. The registry states that no study data are available to report because the data were destroyed. Consequently, the endpoint’s intended clinical meaning can be described, but its observed distribution and any difference between treatment sequences cannot be evaluated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the study as randomized, double-blind, and crossover. It does not report the detailed statistical methods used or planned. The explanations below are general descriptions of concepts relevant to this type of design; they should not be read as a description of analyses actually performed in this trial.

What does randomization contribute?

In general, randomization assigns participants to treatment sequences using a chance-based procedure. Its purpose is to reduce systematic differences between assigned groups at the point of allocation. It does not guarantee that all characteristics will be balanced, especially in a small study, and it does not address problems arising after assignment, such as incomplete follow-up or unavailable outcomes. The registry does not describe the randomization sequence, allocation concealment, or any checks of the allocation process. Since no outcome data are available, the role randomization may have played in the observed results cannot be assessed.

How does a crossover design affect analysis?

In general, a crossover study compares treatments across periods in which participants receive different interventions. Because participants may contribute observations under more than one treatment, an analysis may need to account for the relationship between observations from the same participant. The sequence of treatments and the period in which an outcome occurs can also matter. Carryover is a general concern when an effect from an earlier treatment could persist into a later period. Appropriate handling depends on the study’s clinical and statistical plan, which is not reported in the registry record. The record also does not describe a washout period or a method for assessing period or carryover effects.

The listed sequences place onabotulinumtoxinA and saline in different orders. But the registry descriptions alone do not establish how the treatment switch was handled analytically, whether outcomes were summarized separately by period, or whether the primary comparison was based on within-participant information. Those details are not reported in the registry record. No analysis can be reconstructed from the arm descriptions alone.

What does masking mean for interpretation?

In general, masking is intended to limit the influence of knowledge about assigned treatment on participant responses, clinical assessments, or other study procedures. The entry calls the study double-blind, but does not specify which people were masked or how the injections were made indistinguishable. It also does not report whether masking was assessed. The label therefore describes the registry’s design classification, not evidence that masking was maintained throughout the study.

How should the timing outcome be understood?

The primary outcome refers to days between the last injection and outbreak onset, and days between onset and recurrence. In general, time-to-event methods can be useful when the outcome is the time until an event. Such methods may account for participants whose event is not observed during follow-up, depending on the analysis and the censoring process. That general framework cannot be attributed to this trial: the registry does not name a time-to-event method, define censoring, specify how repeated outbreaks were handled, or state whether the outcome components were analyzed separately. The registry record contains no event-time observations to analyze.

For other outcome types, general analyses might compare group summaries or model repeated measurements, depending on how observations were collected and the assumptions appropriate to the data. The record does not provide the measurement schedule for lesion size, pain, or symptoms beyond their listing as secondary outcomes. Nor does it identify a summary measure or model for these outcomes. Choosing a method without those details would require assumptions that cannot be verified.

What do the planning assumptions represent?

The sample-size planning framework described for the statistical illustrations uses a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It describes the effect to detect as a stated fraction of the observed effect. These are planning assumptions for illustrations, not a report of the trial’s own design justification. The record does not report the trial’s sample-size rationale or its target power. It also does not provide observed effects from which a reader could verify the basis of an illustration. Any planning value should therefore be understood as hypothetical, not as an observed property of the trial or its participants.

The planning notes distinguish time-to-event illustrations, which use total events under the Schoenfeld approach, from other illustrations, which use participants per arm. In general, this distinction reflects that time-to-event precision often depends on the number of observed events, while other designs may be planned around the number of participants. These conventions do not establish that the trial used either method. They also do not amount to observed power. Since the registry reports no outcome data, no trial-specific observed effect or event count can be evaluated from the record.

Overall, statistical concepts can explain what the design and intended endpoint might require, but the missing study data and absent analysis description prevent a reconstruction of the actual analysis. The statistical plan, model specification, handling of missing observations, and interpretation of uncertainty are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary outcome concerning recurrence and duration, as well as secondary outcomes for lesion size, pain assessment, and symptom evaluation. It also reports four outcome measures, but does not explain how those measures relate to each other or how the primary outcome’s two timing descriptions were operationalized. The record does not report a multiplicity strategy, such as whether testing was prioritized, adjusted, or treated as exploratory. It is therefore not possible to determine how the study intended to manage the chance of false-positive findings across multiple outcome assessments.

Missing outcome information is not described as a participant-level pattern of missed visits or incomplete measurements. Instead, the registry states that the study was terminated and the data were destroyed, leaving no study data available to report. It does not provide reasons for termination beyond the data-access and destruction account, nor does it report how many participants had missing measurements, whether any data had been analyzed before destruction, or whether any sensitivity analyses were conducted. These details are not reported in the registry record.

The analysis populations are also not described. The record does not state which participants were randomized, treated, followed, or included in any analysis. It does not report an intention-to-treat population, a per-protocol population, or rules for including participants who did not complete the crossover. Although enrollment is listed as 20, this does not establish the size or composition of an analysis population. The registry reports 0 analyses and contains no outcome data from which an analysis set could be reconstructed.

Consequently, neither multiplicity control nor the handling of missing observations can be evaluated. The absence of these details, combined with the lack of outcome data, prevents assessment of the robustness of any treatment comparison.

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

The registry establishes that a randomized, double-blind crossover study was planned to assess onabotulinumtoxinA as a preventative measure for herpes labialis, with bacteriostatic normal saline as the comparator. It also records the intended primary endpoint and the treatment sequences. These registry entries describe the research question and design, not the findings.

The posted record does not report primary or secondary outcome results. It therefore does not show whether recurrence timing, lesion duration, lesion size, pain, or symptoms differed between the treatment sequences. It cannot establish the size or direction of an effect, or the precision of an estimate. The absence of results must not be interpreted as evidence of no difference or as proof that either intervention did or did not have an effect.

The adverse-event fields are similarly insufficient to establish a safety result. The registry lists 0 at risk and 0 affected for each intervention, and deaths are null. Since the record also says the study data were destroyed and no data are available to report, these entries should not be treated as a complete account of adverse events or deaths. They do not provide an interpretable safety comparison.

The enrollment figure is registry information, not a measure of the amount of analyzable evidence. The record does not report participant flow, completion, outcome availability, or analysis populations. It is also silent about the statistical analysis plan and the justification for the study’s size. These gaps limit what can be learned about the study’s conduct as well as its outcomes.

In short, the record documents an intended clinical comparison but does not provide evidence with which to answer it. It supports a description of the trial design and intended measurements only. Any interpretation beyond that would require study data or methodological details that are not reported in the registry record.

12. Why This Trial Matters Statistically

This study is statistically notable because its intended design and outcome question are recorded, while the data needed to evaluate the comparison are unavailable. That distinction matters: registration information can clarify what investigators set out to study, but it cannot substitute for observed results. Readers need outcome estimates and their uncertainty to assess what the data indicate. Neither is present in the registry record.

The crossover structure also makes the missing methods important. In general, crossover comparisons can use information from treatment periods within participants, but their interpretation depends on period effects, carryover, and the relationship between repeated observations. The registry identifies the treatment sequences but does not report how those features were handled. Without the data and analysis plan, it is not possible to assess whether the intended comparison was statistically appropriate or how precise it might have been.

The planned endpoint adds another interpretive challenge. It refers to elapsed days for outbreak onset and recurrence, but the record does not explain how these components were defined or combined. General statistical methods for event timing depend on details such as follow-up and how unobserved events are treated. No such analysis details or event observations are available.

The record also illustrates why a registry entry should be read with care when outcome fields are empty or adverse-event fields contain zeros alongside an explicit statement that data were destroyed. Those entries do not amount to evidence of no events. The status and data-availability statement are central to understanding what can be concluded.

The trial matters statistically as a documented research question without reportable outcome evidence. Its record can inform readers about the intended comparison and the limits of what is known, but cannot support an estimate of treatment effect or a safety assessment.

13. 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 that the registry reports no study data for analysis. It states that the study was terminated, that the study team no longer had access to the data because the data were destroyed, and that efforts to locate remaining data were unsuccessful. As a result, the primary endpoint and listed secondary outcomes have no reported results.

The registry does not describe participant flow or the availability of measurements during the planned follow-up. Although enrollment is listed as 20, the number randomized, treated, completing follow-up, and included in any analysis is not reported in the registry record. The record also does not provide participant characteristics, eligibility criteria, or reasons for termination beyond the loss of study data.

Important design and analysis details are absent. The registry does not specify treatment doses, injection locations, washout procedures, the roles masked, endpoint definitions, or the statistical analysis plan. It does not explain how the crossover periods or the two timing components of the primary outcome were handled. The sample-size justification, analysis populations, missing-data methods, and multiplicity approach are also not reported in the registry record.

Finally, the adverse-event entries list 0 at risk and 0 affected for both interventions, with deaths recorded as null, but do not provide an interpretable safety dataset in the context of the stated data destruction. These limitations prevent assessment of both efficacy-related outcomes and safety. They are not evidence that outcomes or harms were absent; they describe what the registry record cannot establish.

14. Related Tutorials

15. Related Statistical Calculators

16. Sources

• ClinicalTrials.gov: Botulinum Toxin A for Herpes Labialis — NCT01225341.
• Registry record last updated 2020-12-21; status last verified 2020-11.
• Results first posted 2020-12-21.
• 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.

17. Record Summary

The registry entry concerns NCT01225341, “Botulinum Toxin A for Herpes Labialis,” sponsored by DeNova Research. It describes a randomized, double-blind, placebo-controlled crossover study of onabotulinumtoxinA and bacteriostatic normal saline. Enrollment is listed as 20; study start is recorded as 2010-08, primary completion as 2012-05, and status as TERMINATED.

The primary outcome concerned recurrence and duration of herpes labialis lesions over 12 months. Secondary outcomes included lesion size, pain assessment, and symptom evaluation. The registry states that the study team no longer had access to the study data because the data were destroyed, and that efforts to locate remaining data were unsuccessful. No study data are available to report. The record therefore describes the intended study but does not provide results for evaluating its primary or secondary outcomes.