Evaluation of Systemic Exposure to VP-102 in Subjects With Molluscum Contagiosum.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Evaluation of Systemic Exposure to VP-102 in Subjects With Molluscum Contagiosum. (NCT03186378), a non-randomized phase 2 study. The primary outcome is The Presence or Absence of Systemic Exposure to Cantharidin by the Collection and Analysis of Plasma Samples From Patients With 21 or More Molluscum Lesions Following Treatment of VP-102..

2. Clinical Question

3. Trial Design

This completed Phase 2 study evaluated safety, efficacy, and systemic exposure associated with VP-102 topical film-forming solution containing 0.7% (w/v) cantharidin. The registry lists an enrollment of 33 participants and identifies the study as open label, non-randomized, and single group. It began on 2017-06-08, with primary completion on 2018-06-25.

The registry describes two groups according to lesion burden. The Exposure Group included participants with 21 or more molluscum lesions; its description says participants had to complete all blood draws or be replaced. The Standard Group included participants with 20 lesions or less. Both group descriptions specify treatment with VP-102, so these are not treatment and control groups. The registry does not report random assignment, masking, or a separate untreated comparison.

The primary objective focused on possible systemic cantharidin exposure following a single 24-hour dermal application in pediatric participants aged 2 years and older. The study summary says treatment would continue over 3 additional 21 day intervals to allow further evaluation of safety, efficacy, and quality of life. The registry lists measurement of complete clearance as a secondary outcome.

The safety record lists 17 participants at risk in the Exposure Group and 16 in the Standard Group. Those figures describe the safety listings; the record does not explain how they relate to the stated enrollment or provide a fuller account of the analysis populations. Detailed protocol procedures, including dose application beyond the description above, are not 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.

Overall Study

Reasons for not completing this period:

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: ITT Population

6. Primary Endpoint

The registry lists the primary outcome as The Presence or Absence of Systemic Exposure to Cantharidin by the Collection and Analysis of Plasma Samples From Patients With 21 or More Molluscum Lesions Following Treatment of VP-102., measured over 24 hours.

The primary endpoint asks whether systemic exposure to cantharidin was present or absent after VP-102 was applied to molluscum lesions. The registry describes collection and analysis of plasma samples from participants with 21 or more lesions, with a timeframe of 24 hours. It identifies the measure as a participant count and describes the broader objective as evaluating potential systemic exposure after a single 24-hour dermal application.

This endpoint is distinct from a clinical response such as complete clearance. It is a pharmacokinetic safety question: whether cantharidin was detected in the circulation after topical application. A presence-or-absence measure turns the laboratory assessment into a binary outcome for each participant. The count in each category, together with the number assessed, would be needed to describe the observed frequency and its precision.

The registry record does not report the primary endpoint result, the number of plasma samples analyzed, assay details, detection thresholds, or participant-level findings. It therefore does not establish from the posted primary outcome whether exposure was detected or absent. Nor does the absence of a posted endpoint result imply that no exposure occurred. Complete-clearance outcome results and their timing are also not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a non-randomized, open-label, single-group study. It does not report a detailed statistical analysis plan or analysis results. The methods concepts below are general explanations of how the stated outcome and design can be interpreted; they are not claims about analyses performed in this study.

What does a binary endpoint represent?

A presence-or-absence outcome is binary: each assessed participant is classified into one of two outcome categories. For the primary question, those categories concern whether systemic cantharidin exposure was detected in plasma. A participant count can describe how many assessed participants fall into each category. To interpret such counts, readers also need the number of participants assessed and a clear definition of how the laboratory result was classified.

For a binary endpoint, a proportion is often used to express the share of assessed participants in a category. A confidence interval can show the uncertainty around an estimated proportion: narrower intervals indicate greater precision, while wider intervals indicate less precision. These are general statistical concepts. The registry record does not report the primary counts, a proportion, a confidence interval, or the assay rule used to classify exposure. No such estimate can therefore be interpreted from the posted primary outcome.

What does the study design allow?

In a randomized comparison, allocation can help make groups comparable with respect to both measured and unmeasured characteristics, on average. This study was not randomized. Its groups were defined by lesion burden, with 21 or more lesions in the Exposure Group and 20 lesions or less in the Standard Group. Both groups received VP-102. As a result, these groups do not form a randomized treatment-versus-control contrast.

Comparisons between groups defined by baseline characteristics can be affected by differences related to those characteristics or by other imbalances. A raw difference in outcomes would be descriptive and would not, on its own, show that group membership or treatment caused the difference. The registry record does not report an adjusted comparative analysis, a causal analysis, or details about measured baseline characteristics.

How should a confidence interval be read?

Generally, a confidence interval expresses sampling uncertainty under the assumptions of the statistical method used. It is not a guarantee that the true value lies within a particular interval, and it does not address every source of bias or measurement error. For this endpoint, uncertainty would depend in part on how many participants had evaluable plasma samples and how exposure was defined. Neither the primary outcome counts nor an interval estimate is reported in the registry record.

When a study reports a count without an interval, the count can still be described, but the precision of an estimated frequency is less apparent. A result based on a small number of observations can be uncertain even when the observed count appears straightforward. That is general guidance, not a numerical conclusion about this trial; no primary result is posted from which to evaluate precision.

Why do denominators and missing measurements matter?

A denominator identifies how many participants contributed to an outcome. For a plasma assessment, the enrolled population, participants who received the application, participants who completed blood draws, and participants with analyzable samples could differ. The Exposure Group description says participants had to complete all blood draws or be replaced, but the registry does not report the number replaced, the number with samples analyzed, or how missing or unusable samples were handled. Without those details, a count cannot be interpreted as a complete accounting of all enrolled participants.

Missing outcome data can affect interpretation when participants with missing measurements differ from those with observed measurements. General approaches include reporting the amount and reasons for missingness and explaining how the primary analysis handled it. No such handling is reported in the registry record. The record also does not state a primary analysis population such as all enrolled participants or all participants with evaluable samples.

What do the listed safety counts describe?

The serious adverse event figures are participant counts, not estimates of the primary plasma endpoint. The record lists the number at risk and the number affected for each group. General interpretation of an event count depends on the definition of the event, the observation period, ascertainment procedures, and the denominator. The available record does not provide detailed definitions or event-level descriptions for the other adverse-event counts. It lists no serious adverse event terms.

The study summary mentions further treatment over 3 additional 21 day intervals, while the primary endpoint timeframe is 24 hours after a single application. These refer to different aspects of the study: the stated primary exposure assessment and the broader planned evaluation period. The registry does not report the timing of the safety events or detailed outcome-specific analysis windows beyond the primary timeframe.

Finally, the registry lists 7 outcome measures and 0 analyses. It does not describe whether there were interim analyses, how multiple outcomes were handled, what statistical models were prespecified, or how sample size was justified. Those matters are not reported in the registry record, so no particular analysis method or multiplicity adjustment should be attributed to the study.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures, including the primary systemic exposure measure and the secondary measure of complete clearance. It also lists 0 analyses. The record does not report a multiplicity strategy, such as a hierarchy of outcomes or an adjustment for testing multiple outcomes. Without that information and without posted outcome results, the role of any statistical testing across outcomes cannot be assessed.

Missing-data handling is also not reported in the registry record. The Exposure Group description says participants had to complete all blood draws or be replaced, but it does not state how many participants were replaced, whether samples were missing or unevaluable, or how such cases were handled in the primary analysis. The record does not report the number of participants included in each outcome analysis.

The analysis populations are not reported in the registry record. In particular, the record does not clarify whether the primary endpoint was evaluated among all enrolled participants, only those who completed blood draws, or only those with analyzable plasma samples. It also does not state whether secondary outcomes used the same participants or population. These details matter because the group initially enrolled, the group observed, and the group included in an analysis need not be identical.

No interim analysis plan, stopping rule, or detailed statistical plan is reported in the registry record. These omissions should be treated as unknowns, rather than evidence that a particular method was or was not used.

11. 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 5% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse event listing reports 0 affected participants in the Exposure Group, with 17 at risk, and 0 affected participants in the Standard Group, with 16 at risk. It also records 0 deaths in each group and lists no serious adverse event terms. These are the registry's posted safety counts; they do not answer whether cantharidin was detected in plasma.

The registry separately reports other adverse-event counts: 16 affected participants among 17 at risk in the Exposure Group and 13 among 16 at risk in the Standard Group. The record does not give the terms, severity, timing, or treatment relationship for these other events in the information. The counts should therefore be read as summary participant counts, not as a description of specific symptoms or a causal assessment.

A count of zero serious adverse events in the posted record is not proof that an intervention has no risks. Interpretation depends on the number observed, the observation period, event definitions, and completeness of reporting. The registry does not report detailed event-level information or the methods used to collect and classify adverse events. The groups are non-randomized and differ by lesion-count criteria, so their safety counts are not a like-for-like comparative estimate.

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

The record establishes that a Phase 2, open-label, non-randomized study of VP-102 was completed and that its primary question concerned systemic cantharidin exposure in plasma after a single 24-hour dermal application. It also reports selected participant counts for serious and other adverse events. These registry entries describe the study and the posted safety summary, but they do not supply the primary exposure result.

Because the primary endpoint count and its denominator are not reported in the registry record, the posted information does not establish whether exposure was detected or absent. It also does not permit an assessment of how precise an estimated exposure frequency would be. The registry lists complete clearance as a secondary outcome, but does not report that result either. No conclusion about efficacy follows from the information reported.

The absence of serious adverse events in the listed counts should be interpreted narrowly. It describes what the registry reports for the safety groups, not a guarantee about all possible risks or a definitive estimate for a broader population. The other adverse-event counts are not accompanied by event descriptions in the available record, limiting interpretation of their clinical meaning.

Both groups received VP-102, and group assignment was non-randomized according to lesion-count categories. The study therefore does not provide a randomized control comparison from which to attribute differences between groups to treatment. The registry record also does not report enough information about analysis populations, missing samples, or methods to reconstruct a detailed statistical analysis.

In short, the posted record supports an account of the trial's design, intended primary measure, and selected safety counts. It does not report the main endpoint result or the secondary clearance result, and it does not support a conclusion about systemic exposure or efficacy.

13. Why This Trial Matters Statistically

This trial raises a statistical question that differs from a conventional comparison of clinical outcomes: whether cantharidin was detectable in plasma after topical application. The endpoint is framed as presence or absence, making the number of participants assessed and the classification of each plasma result central to interpretation. Without those outcome counts, readers cannot determine what the primary assessment observed or how precisely it was estimated.

The design also illustrates why group labels should be read carefully. Although the registry names an Exposure Group and a Standard Group, both groups received VP-102; the distinction is lesion burden. Because the study is non-randomized, the groups are not an untreated control and a treatment arm. Their counts can be described separately, but a contrast between them would not, by itself, isolate a treatment effect.

For clinical researchers, the record highlights the importance of reporting denominators and the flow of participants through outcome assessment. The Exposure Group description makes completion of blood draws a condition, but the registry does not report the number with analyzable plasma samples or the handling of missing measurements. Those details are especially relevant when the primary outcome depends on laboratory testing.

The record also lists multiple outcomes while providing no analysis results or stated multiplicity approach. This makes it difficult to understand the prespecified inferential framework. More complete reporting of endpoint counts, assay interpretation, analysis populations, missing data, and methods would allow a clearer assessment of the evidence and its uncertainty.

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 is the absence of the primary endpoint result in the registry record. There is no reported count for plasma exposure, no evaluable-sample denominator, and no measure of precision. The assay method, detection threshold, and rule for classifying exposure are also not reported, so the endpoint cannot be independently interpreted from the record.

The study is non-randomized and open label. Its two groups are defined by lesion burden and both receive VP-102, so they do not provide a like-for-like control comparison. The registry does not report detailed baseline characteristics that could help describe how the groups differ beyond their lesion-count criteria. Nor does it report adjusted analyses.

Although the Exposure Group description refers to completing all blood draws or being replaced, the record does not state how many participants were replaced, whether samples were missing or unevaluable, or how these cases were handled. The analysis populations are not reported. This limits assessment of the relationship between enrollment, observed outcomes, and the participants included in any analysis.

The registry lists a secondary complete-clearance outcome but does not report its result. It lists 7 outcome measures and 0 analyses, without a reported statistical plan, multiplicity approach, sample-size justification, or interim analysis details. These items are not reported in the registry record; their absence should not be interpreted as evidence about what procedures may have been used outside the posted record.

Safety information is also limited to summary counts. The record does not provide the terms and details for other adverse events, their timing, or their relationship to treatment. These limitations restrict both the clinical interpretation of the safety counts and the ability to assess the overall findings.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Evaluation of Systemic Exposure to VP-102 in Subjects With Molluscum Contagiosum. — NCT03186378.
• Registry record last updated 2021-08-11; status last verified 2021-08.
• Results first posted 2021-08-09.
• 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

NCT03186378 is a completed Phase 2, open-label, non-randomized, single-group study sponsored by Verrica Pharmaceuticals Inc. It enrolled 33 participants and evaluated VP-102, a topical film-forming solution containing 0.7% (w/v) cantharidin, in participants aged 2 years and older with molluscum contagiosum. The study began on 2017-06-08 and reached primary completion on 2018-06-25.

The primary endpoint asked whether systemic cantharidin exposure was present or absent in plasma within 24 hours after application to participants with 21 or more lesions. The primary result is not reported in the registry record. Complete clearance is listed as a secondary outcome, but its result is also not reported. Safety listings record zero serious adverse events and zero deaths in each group; other adverse-event counts are 16 of 17 and 13 of 16. The record does not provide further details for those other events.