Safety and Efficacy Study of Topical Cantharidin for the Treatment of Molluscum Contagiosum: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Safety and Efficacy Study of Topical Cantharidin for the Treatment of Molluscum Contagiosum (NCT02665260), a randomized phase 2 study. The primary outcome is Number of Subjects Who Achieve Complete Clearance at 6 Weeks.

2. Clinical Question

3. Trial Design

The registry record identifies NCT02665260 as a completed Phase 2 randomized pilot study sponsored by Montefiore Medical Center. The study is described as randomized, triple-masked, and parallel. Enrollment is listed as 94. The recorded start is 2012-07 and primary completion is 2015-11. The record does not report the identities of the parties who were masked, the randomization method, or the allocation ratio.

Four arm descriptions appear: cantharidin 0.7% topical with occlusion, cantharidin 0.7% topical without occlusion, placebo topical with occlusion, and placebo topical without occlusion. Gauze occlusion bandage is listed as a device. The registry also lists cantharidin and placebo as drug interventions. Further details about administration, adherence, treatment duration, or how the open-label phase related to the earlier study period are not reported in the registry record.

The primary outcome is the number of participants achieving complete clearance at 6 weeks, defined by a lesion count of zero at the end of the open-label phase. The secondary outcome is the number of participants who experienced an adverse event. Although the registry identifies two outcome measures, it reports no analyses. The primary outcome is not reduced to one comparison because it has several categories or time points, as noted in the record. This means the study design and intended outcome can be described, but a comparative efficacy result cannot be reconstructed from the posted information.

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: A total of 6 subjects met exclusion criteria for having greater than 50 molluscum contagiosum lesions at screening.

Overall Study

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 Number of Subjects Who Achieve Complete Clearance at 6 Weeks, measured over 6 weeks.

Complete clearance is defined as having a lesion count of zero at 6 weeks, at the end of the open-label phase. The registry describes the measure as a count of participants, rather than reporting an individual lesion-count change or a continuous score. At the participant level, the outcome distinguishes those who meet the zero-lesion definition from those who do not; the summary measure is the number meeting that definition.

General: A complete-clearance endpoint can be clinically interpretable because it uses a stated threshold rather than requiring a reader to judge the meaning of an average change in lesion count. It also makes the assessment time important: the outcome pertains to the specified 6-week visit, not to a different time point or to longer-term persistence. The registry record does not report additional details about how lesion counts were assessed, who assessed them, or whether assessments were independently confirmed.

The record does not include the number of participants achieving clearance in any arm, the number assessed at 6 weeks, or a comparison between arms. It therefore establishes what the primary endpoint was intended to measure, but not the observed clearance results or their precision.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the primary outcome count?

The primary outcome is a count of participants who achieve complete clearance at 6 weeks. Clearance is defined as a lesion count of zero at the end of the open-label phase. This is an endpoint measured at a specified follow-up time. It is not a report of the average number of lesions, the change from baseline, or the time taken to reach clearance. Those measures are not reported as the primary outcome in the registry record.

General: When an outcome records whether each participant meets a defined criterion, the individual outcome is binary: the criterion is either met or not met. Group summaries may then report the number meeting the criterion, and comparative analyses may use those counts with the relevant denominators. A count alone is not enough to determine a rate or compare groups; the number assessed in each group and the analysis method also matter. The registry record does not report primary-outcome counts or denominators by arm.

What does randomization contribute?

The record describes the study as randomized. General: Random assignment is intended to make treatment groups comparable, on average, with respect to measured and unmeasured characteristics at the point of assignment. It does not guarantee that every characteristic is balanced, particularly in a pilot study, and it does not replace reporting the actual outcome data. The randomization procedure, allocation ratio, and any stratification factors are not reported in the registry record.

The design is also listed as parallel, meaning the record classifies participants into treatment groups rather than identifying a crossover design. The trial is described as triple-masked, but the record does not identify which people or roles were masked or how masking was maintained. General: Masking can reduce the influence of expectations on care, assessment, or reporting, depending on who is masked and how the study is conducted. The designation alone does not establish which potential sources of bias were addressed in this trial.

How should an effect estimate and its precision be read?

General: A comparative effect estimate summarizes the difference or other contrast between treatment groups for a defined outcome. A confidence interval gives a range of values compatible with the data and the specified statistical procedure. Its width reflects precision: wider intervals indicate less precise estimates, while narrower intervals indicate greater precision. The interval is not a guarantee that the true effect lies within its limits.

No primary-outcome estimate or confidence interval is reported in this registry record. The record also lists zero analyses, so no reported test statistic or p-value is available for the primary comparison. It is not possible to judge whether a result is statistically distinguishable from a null value, or whether the range of plausible effects is narrow or wide. A trial’s phase, masking, or enrollment figure cannot substitute for these estimates.

What can the sample-size assumptions tell us?

The registry’s sample-size description characterizes its calculations as planning illustrations based on an observed effect, not as the trial’s own design. It specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. The record does not report the trial’s own sample-size justification or provide the efficacy result needed to assess an observed effect in this analysis.

General: A sample-size calculation asks how many participants might be needed under stated assumptions to detect an effect of a chosen size with a specified probability, if those assumptions hold. Such calculations are planning illustrations, not observed power. They do not show that an effect occurred, and they do not recover a missing outcome analysis. Because the registry record does not report the observed primary effect or the calculated participant figures in the registry record for this interpretation, no numeric planning result can be stated.

Why is the outcome structure important?

The record states that the primary outcome has several categories or time points and was not reduced to one comparison. General: When studies report multiple outcomes, time points, or treatment contrasts, the chosen analysis affects which question a result answers. Selecting one result after seeing many can increase the chance of a misleading finding. A prespecified analysis plan can clarify which comparison is primary and how other analyses are treated. The registry record does not report such a plan, a multiplicity adjustment, or an analysis corresponding to a single primary comparison.

These statistical concepts help explain what would be needed to interpret the trial’s efficacy evidence. They do not supply an estimate where the registry reports none. The central limitation is the absence of reported primary outcome results and analyses, not the inability to apply a statistical method to the information that is present.

10. Multiplicity, Missing Data and Analysis Populations

The registry identifies two outcome measures: complete clearance at 6 weeks and the number of participants who experienced an adverse event. It also notes that the primary outcome has several categories or time points and was not reduced to one comparison. The registry record does not report a prespecified hierarchy among comparisons, a multiplicity adjustment, or an analysis plan explaining how multiple outcomes, time points, or treatment contrasts were handled.

General: When several hypotheses are tested, the chance of at least one apparently unusual result can increase if the results are interpreted without accounting for the number of comparisons. An analysis plan can state which comparison is primary and whether or how other tests are adjusted. Because no analyses are reported, the effects of multiplicity on any efficacy conclusion cannot be assessed.

Missing-data methods and analysis populations are not reported in the registry record. It does not state how participants without a 6-week assessment were handled, whether all randomized participants were included in the primary analysis, or whether any per-protocol or other analysis population was used. The at-risk counts in the adverse-event entries do not establish the number with an observed primary outcome.

General: Missing outcomes can affect both the denominator and the interpretation of a group comparison. A transparent report commonly explains how much outcome data are missing and what assumptions or methods were used to address that missingness. Without those details and the primary results, neither the potential influence of missing data nor the robustness of an efficacy estimate can be evaluated from this registry record.

11. 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 0% reporting threshold.

The adverse-event entries list four groups. For Cantharidin, 23 participants were at risk for serious adverse events and 0 were affected; 23 were at risk for other adverse events and 0 were affected. For Cantharidin With Occlusion, the corresponding counts are 24 at risk and 0 affected for serious adverse events, and 24 at risk and 0 affected for other adverse events. For Placebo, the counts are 22 at risk and 0 affected for each category. For Placebo With Occlusion, the counts are 25 at risk and 0 affected for each category.

These are group-level registry entries, not a detailed description of event types, severity, timing, or duration. No serious adverse-event terms are listed. Deaths are not reported in the registry record; a missing death entry should not be read as a reported zero. The record does not provide a comparative safety analysis or further information about how adverse events were collected. General: Zero reported events in these entries describes the posted counts, but it does not prove that a treatment is free of risk or that all possible events were captured.

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

The record establishes that NCT02665260 was a completed randomized, triple-masked Phase 2 pilot study of topical cantharidin and placebo conditions, with and without occlusion, for molluscum contagiosum. It specifies complete clearance at 6 weeks as the primary outcome and describes clearance as a lesion count of zero at the end of the open-label phase. It also reports group-level adverse-event counts.

Those design details do not establish whether cantharidin produced more, fewer, or the same number of complete clearances than placebo. The registry record does not report arm-level clearance counts, a comparative effect estimate, a confidence interval, or a statistical test. It therefore cannot support a conclusion about the direction, magnitude, or precision of an efficacy difference. No primary analysis is reported.

The adverse-event entries show zero affected participants for both serious and other adverse events in each listed group. That is a description of the entries, not a complete assessment of safety. The record does not provide adverse-event terms, deaths, collection details, or a comparative analysis. The deaths field is not reported in the registry record.

General: A study’s design describes how evidence was intended to be generated; results are needed to determine what the observed data show. Randomization and masking are relevant design features, but neither can replace outcome reporting. The available record permits a description of the study question and design, but not a conclusion that a treatment works or does not work. It also does not establish how applicable the results might be to people or settings beyond those actually studied, which are not fully characterized in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically noteworthy because its registry record combines a defined randomized design with an outcome question that is not accompanied by a reported efficacy analysis. The primary endpoint is concrete: complete clearance at 6 weeks, defined as a lesion count of zero. Yet the record does not state how many participants met that definition in any arm, or provide a comparison. This distinction between a clearly described endpoint and an available result is essential when reading trial registries.

The four treatment descriptions also illustrate why a question about treatment effects needs a clearly reported comparison. Cantharidin and placebo are each described with and without occlusion, but the statistical plan for comparing these conditions is not reported in the registry record. Without specified contrasts and results, readers cannot determine which treatment question an analysis would answer or assess possible differences associated with occlusion.

The record also makes visible the limits of safety counts without event detail or analysis. Zero affected participants are recorded in the serious and other adverse-event entries, but the record does not report deaths, event terms, or a comparative safety assessment. A count should be read within the scope and detail of the report rather than treated as a complete account of risk.

General: Statistical interpretation depends not only on study design but also on transparent outcome definitions, denominators, estimates, uncertainty, and analysis methods. This record is a useful example of why readers should distinguish a study’s intended question from evidence that can answer it. Where results or methods are absent, those gaps limit inference; they should not be filled by assumptions about the protocol or by calculations that the record does not support.

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 trial-specific limitation for interpretation is that the registry record does not report the primary outcome results or any analyses. Although complete clearance at 6 weeks is defined, the record gives no arm-level clearance counts, denominators, effect estimate, confidence interval, or test. It also states that the primary outcome has several categories or time points and was not reduced to one comparison. A comparative efficacy conclusion therefore cannot be drawn from the posted information.

The record does not report participant eligibility criteria, age range, baseline lesion burden, or other characteristics needed to describe the enrolled population in detail. Its brief summary refers to kids, but further demographic and clinical information is not reported in the registry record. Details of the application schedule, treatment duration, outcome-assessment procedures, and the relationship of the open-label phase to other study periods are also not reported.

Several design and analysis details are unavailable: the randomization method and allocation ratio, the identities of those masked, the analysis populations, missing-data handling, and the statistical plan. The record does not explain how multiple categories, time points, or treatment contrasts were handled. The adverse-event entries provide counts but not event terms or collection details, and deaths are not reported in the registry record.

These gaps do not show that the study was conducted improperly; they identify what cannot be evaluated from this registry record. General: Complete reporting allows readers to assess both the result and the assumptions behind its analysis. In its absence, interpretations should remain limited to the study features and counts that are actually recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Safety and Efficacy Study of Topical Cantharidin for the Treatment of Molluscum Contagiosum — NCT02665260.
• Registry record last updated 2017-05-05; status last verified 2017-03.
• Results first posted 2017-05-05.
• 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.

18. Record Summary

NCT02665260 is listed as a completed Phase 2 randomized, triple-masked, parallel pilot study sponsored by Montefiore Medical Center. Enrollment was 94. The record lists cantharidin 0.7% topical and placebo, each with and without occlusion, and identifies gauze occlusion bandage as a device. The primary outcome is the number of participants achieving complete clearance at 6 weeks, defined as a lesion count of zero at the end of the open-label phase.

The registry record reports no analyses and does not provide primary outcome counts or an efficacy comparison. Its adverse-event entries list zero affected participants for serious and other adverse events in each group; deaths are not reported in the registry record. Randomization details, analysis populations, missing-data methods, and the statistical plan are also not reported. The record therefore describes the study question and design but does not provide enough outcome evidence to interpret comparative efficacy.