A Placebo-Controlled Study Using VP-102 in the Treatment of External Genital Warts: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Placebo-Controlled Study Using VP-102 in the Treatment of External Genital Warts (NCT03981822), a randomized phase 2 study. The primary outcome is Proportion of Subjects Exhibiting Complete Clearance of All Treatable Warts at the Study Day 84 (End of Treatment) Visit..

2. Clinical Question

The design puts the outcome question in context. The study was randomized, double-blind, placebo-controlled, and parallel, with quadruple masking recorded. Its stated purpose was to evaluate dose regimen, efficacy, safety, and tolerability. Part A assessed different exposure durations before progression to Part B, while Part B used selected durations. The record does not state how the dose regimens were selected for Part B.

The primary outcome is limited to a particular assessment: Day 84, identified as end of treatment. Other registry outcomes cover clearance thresholds, wart counts, and additional visits. Those are related measures, but they do not answer exactly the same question as complete clearance at Day 84. In particular, a partial-clearance measure is not interchangeable with the complete-clearance outcome.

The registry record reports enrollment of 105. Its brief summary describes approximately 108 subjects for Parts A and B. Those are different descriptions in the record, and the available information does not explain the difference. The posted primary outcome population is specified as intent-to-treat, with Part B pooled with its respective Part A treatments. Details of the analysis population for each other outcome are not reported in the registry record.

3. Trial Design

This was a randomized, parallel-group Phase 2 study comparing VP-102 regimens with placebo in people with external genital warts. The record describes the study as double-blind and records quadruple masking. It was organized in Part A and Part B. The registry reports enrollment of 105 and status as completed. The recorded study start was 2019-06-25, and primary completion was 2020-05-21.

Part A evaluated VP-102 with exposure durations of 2 hours, 6 hours, and 24 hours, alongside placebo schedules. Part B included VP-102 and placebo regimens with 6-hour or 24-hour exposure. In both parts, the active regimen was applied every 21 days for 4 treatments. The record describes Part A as evaluating increasing durations of skin exposure before progressing to Part B. It does not report the selection procedure or criteria used to determine which regimens progressed.

The follow-up schedule in the brief summary includes assessments at Day 84, Day 112, and Day 147. Day 84 is identified as end of treatment for the primary outcome; Day 147 is identified as end of study in the secondary-outcome descriptions. Secondary outcomes also include assessments at treatment visits. The registry record does not provide a detailed visit-by-visit schedule for every outcome beyond those descriptions.

The primary outcome population is Part B and Part A: intent-to-treat, with Part B pooled with its respective treatments from Part A. This pooling is important when reading the comparison: the posted record describes combining corresponding treatment information across parts, not a single undifferentiated comparison across all exposure schedules. It does not report the allocation ratio, the number assigned to each regimen for the primary analysis, or the detailed rules defining the pooled groups.

The record lists 10 outcome measures and 88 analyses. Those counts indicate that the registry contains multiple outcome and analysis entries, but they do not by themselves identify which results should be treated as confirmatory or how comparisons were prioritized. The registry record does not report a statistical analysis plan, the rationale for the enrollment target, or details of interim analyses. The brief summary refers to approximately 108 subjects, whereas the enrollment field records 105; the registry does not explain that difference.

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: All subject numbers are based on ITT population. Participants in Part A 6-hour and 24-hour group were also included in Part B subject populations.

Only the first 6 of 8 groups are shown.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Part B and A: Intent-to-Treat Population. Part B summary is pooled with its respective treatments from Part A.

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

Only the first 6 of 9 groups are shown.

6. Primary Endpoint

The registry lists the primary outcome as Proportion of Subjects Exhibiting Complete Clearance of All Treatable Warts at the Study Day 84 (End of Treatment) Visit., measured over Compares baseline wart count to Day 84, end of treatment..

The primary endpoint is the proportion of subjects exhibiting complete clearance of all treatable warts at the Study Day 84 end-of-treatment visit. The description explicitly includes baseline and new warts. The timeframe compares the baseline wart count with the Day 84 assessment. The stated analysis population is the Part B and Part A intent-to-treat population, with Part B pooled with its respective treatments from Part A.

Statistically, complete clearance is a binary participant-level outcome. Each participant is classified according to whether all treatable warts meet the endpoint definition at the specified assessment. A proportion expresses the frequency of participants meeting that definition relative to the participants included in the analysis. The registry record identifies the outcome parameter as a participant count, but the comparative results needed to interpret the primary question are not reported in the available record information.

General statistical context: a complete-clearance endpoint can be useful because it represents an all-or-none status at a defined time, rather than a degree of change in wart count. It is also easy to distinguish conceptually from outcomes such as 75% or 90% clearance, which allow residual warts. The choice of a particular threshold determines what event is counted; results for different thresholds should therefore be interpreted as different outcomes, not as alternate presentations of the same endpoint.

The endpoint is tied to Day 84. It does not, on its own, describe what happened at every treatment visit or whether clearance was maintained at later follow-up. The registry lists additional complete-clearance assessments at later visits among secondary outcomes, but their numerical results are not reported in the information available for this analysis. The registry record also does not report the operational criteria used to determine whether every wart was treatable or how missing Day 84 assessments were handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is binary at the participant level: complete clearance at Day 84 is the event of interest, and the outcome is recorded as a participant count. In general, binary outcomes are commonly summarized by the number meeting the endpoint and the number assessed in each group, along with a proportion and a treatment contrast. The contrast may be expressed in more than one way, and each measure has a different interpretation. The registry information does not report the primary group counts, comparative effect estimate, or its uncertainty, so no particular contrast can be interpreted.

What does a confidence interval communicate?

General statistical explanation: a confidence interval represents uncertainty around an estimate. Its width reflects precision under the assumptions of the method used: a wider interval conveys less precision than a narrower one. It is not a guarantee that the true effect lies within the interval, nor does an interval alone establish whether an effect is important. To interpret one, readers need the estimate, the interval, the outcome definition, and the analysis population. The registry record does not report a confidence interval for the primary comparison in the information.

Why distinguish the outcome thresholds?

The registry describes complete clearance and, among secondary outcomes, 90% clearance and 75% clearance. General statistical explanation: thresholds define which participants count as having an event. A less stringent threshold can classify a different set of participants than complete clearance, so the resulting proportions answer different questions. These threshold outcomes should not be combined or treated as substitutes for one another. The record also lists changes in wart counts and percent changes from baseline. Those are count-based or change outcomes, not the same binary classification as complete clearance.

What is over-dispersion, and does it apply?

General statistical explanation: over-dispersion occurs when count data vary more than expected under a model’s assumptions. It can matter when modelling counts because standard errors may be too small if that extra variation is ignored. The registry lists wart-count outcomes, but the statistical model used for them is not reported in the registry record. The primary endpoint is described as a participant count for a binary outcome, so the record does not establish that an over-dispersion adjustment was used or was needed for that endpoint.

What does the intent-to-treat label tell readers?

The registry identifies the primary analysis population as Part B and Part A: intent-to-treat, with Part B pooled with its respective treatments from Part A. General statistical explanation: an intent-to-treat approach usually aims to retain participants in the groups to which they were assigned, which can preserve the benefits of randomization. The label alone does not specify how missing assessments, treatment changes, or other deviations were handled. Those operational rules are not reported in the registry record.

How should planning calculations be read?

The stated planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. General statistical explanation: planning calculations use assumptions about the effect and design to illustrate the sample size that might be needed for a future study. They are not evidence that the completed trial had a particular probability of detecting an effect, and they do not describe the trial’s observed result. The planning figures are illustrations based on the observed effect, not the trial’s own design justification. The registry record does not report the trial’s sample-size justification.

The record states that the planning calculation uses participants per arm for non-time-to-event outcomes and total events for time-to-event outcomes. The primary endpoint is binary rather than time-to-event. No sample-size illustration values are reported in the registry information. General statistical explanation: the normal approximation is a simplifying method for estimating uncertainty or planning under specified conditions; its suitability depends on the data and analysis. The record does not provide enough information to assess the calculation details or reproduce the planning values.

What can the analysis count establish?

The record lists 10 outcome measures and 88 analyses. General statistical explanation: a larger set of outcome and analysis entries can raise questions about multiplicity, because repeated statistical testing can increase the chance of at least one apparently unusual result under a null model. Appropriate interpretation depends on which comparisons were prespecified, which were primary, and whether an adjustment or hierarchical procedure was used. The registry record does not report those details. The number of analyses alone does not show that a particular correction was used or that any reported finding is false.

For safety, the registry reports counts of participants with serious adverse events and the number at risk within each listed group. These are descriptive counts. General statistical explanation: rare-event estimates can be imprecise, especially when group sizes and event counts are limited; a zero count does not establish that the underlying risk is zero. The registry record does not report the event definitions, event-collection window, or inferential method needed to assess a comparative safety effect. No causal conclusion follows from the group counts alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 88 analyses. Its outcome descriptions include different clearance thresholds, changes in wart counts, and assessments at treatment and follow-up visits. When many outcomes or comparisons are examined, multiplicity is a statistical concern: repeated testing can make chance findings more likely. General statistical explanation: prespecifying a primary comparison and using an appropriate adjustment or testing hierarchy can help control that concern. The registry record does not report whether a multiplicity adjustment, hierarchy, or other strategy was used. The number of analyses alone does not reveal the statistical plan.

The primary outcome population is stated as the Part B and Part A intent-to-treat population, with Part B pooled with its respective treatments from Part A. This describes the population label and pooling approach, but not every analysis detail. The registry record does not report the number of participants included in each primary group, the handling of participants without a Day 84 assessment, or whether any sensitivity analyses were conducted.

Missing-data methods are not reported in the registry record. This matters because the interpretation of a proportion depends on who contributes to its denominator and on how unavailable assessments are handled. General statistical explanation: excluding participants with missing outcomes, assigning an outcome status, or using a model-based method can lead to different estimates under different assumptions. The record does not state which approach was used, so the effect of missing data on the primary estimate cannot be assessed.

The record also does not report the statistical analysis plan, a sample-size justification, or interim-analysis procedures. The brief summary describes approximately 108 subjects, while the enrollment field records 105; no explanation for that difference is reported in the registry record. These gaps limit evaluation of prespecification and analysis decisions, but they do not by themselves establish that any 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pneumonia (5.0%), bipolar disorder (4.5%), musculoskeletal chest pain (3.4%).

The registry reports serious adverse event counts by treatment group. In the Part B pooled with Part A 6-hour VP-102 group, 1 participant with a serious adverse event is listed among 29 at risk; in the corresponding 6-hour placebo group, 1 is listed among 22 at risk. In the pooled 24-hour VP-102 group, 0 are listed among 28 at risk; in the corresponding 24-hour placebo group, 1 is listed among 20 at risk. For Part A’s 2-hour groups, 0 are listed among 5 at risk for VP-102 and 0 among 1 at risk for placebo. No group totals are calculated.

The record lists 0 deaths in each of the six groups. It also lists Pneumonia at 5.0%, Bipolar disorder at 4.5%, and Musculoskeletal chest pain at 3.4% as the top serious terms. The denominator for those percentages and their group attribution are not reported in the registry record.

These figures are counts, not proof that treatment caused or prevented an event. General statistical explanation: safety counts are easier to interpret when the event definition, observation period, denominator, and method of collection are known. Those details are not reported. A zero count in a group does not demonstrate zero underlying risk, and counts across groups should not be compared as if they were adjusted estimates. The registry record does not provide a formal comparative safety analysis in the information available for this interpretation.

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

The record describes a randomized, placebo-controlled Phase 2 study of VP-102 regimens for external genital warts. Its primary question concerns complete clearance of all treatable warts, including baseline and new warts, at the Day 84 end-of-treatment visit. The endpoint definition and the stated analysis population are available, as are descriptive serious adverse event counts for the listed groups.

The primary comparative result is not reported in the registry information available for this analysis. Without group-specific primary outcome results and an uncertainty measure, the magnitude and precision of any difference cannot be assessed. The endpoint description alone does not show how many participants achieved complete clearance or whether the groups differed. This absence of a reported result should not be read as evidence of either benefit or no benefit.

The safety counts also have limits. They describe participants with serious adverse events in each listed group, but the record does not provide the event definitions, observation window, or a comparative statistical analysis. The listed serious-event terms and percentages cannot be assigned to particular groups from the available information. Counts and percentages should not be interpreted as establishing causation.

General statistical context: an estimate is most informative when paired with its uncertainty, a clearly defined outcome, and an analysis population. A statistically detectable difference, if reported, would not by itself establish clinical importance; conversely, an imprecise estimate would not establish equivalence. No primary estimate or interval is reported, so those distinctions cannot be evaluated.

The study’s Phase 2 designation and dose-regimen purpose provide design context, not a conclusion about treatment effects. The registry record does not report the rationale for the enrollment target, the full statistical plan, missing-data methods, or multiplicity procedures. Consequently, the posted information supports a description of the research question, design, and selected safety counts, but not a definitive interpretation of comparative efficacy or safety.

13. Why This Trial Matters Statistically

This study illustrates why endpoint definitions and assessment times matter. Complete clearance at Day 84 is a specific binary outcome. The registry also describes 90% and 75% clearance, wart-count changes, and assessments at other visits. Each of these outcomes captures a different aspect of the data. An estimate for one threshold or visit would not automatically answer the primary question about complete clearance at end of treatment.

The design also includes multiple exposure durations and two study parts. The primary population description pools Part B with its respective treatments from Part A. That detail matters when identifying the intended comparison and avoiding an assumption that every active regimen or placebo schedule belongs in one common contrast. The record does not explain the selection process for the regimens used in Part B.

The registry lists 10 outcome measures and 88 analyses, making prespecification and multiplicity relevant topics for interpretation. Without a reported analysis plan, readers cannot determine how comparisons were prioritized or whether statistical adjustment was applied. This is an important distinction between the existence of many analyses and the evidence supporting any individual result.

The safety record offers group-specific counts, including serious adverse events and deaths, but not the detail needed for causal or adjusted comparisons. These counts are useful as descriptive information, yet they do not replace an analysis that accounts for the outcome definitions, observation periods, and uncertainty. The lack of a reported primary comparative result is also a reminder that a clearly specified question is not the same as a reported answer. Here, the registry establishes what was intended to be measured, but the available record does not permit assessment of the primary treatment contrast.

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 principal limitation for interpretation is the absence of the primary outcome results in the registry information available for this analysis. The endpoint is described, but the group-specific counts, comparative effect, and uncertainty are not reported. A conclusion about the direction, size, or precision of a treatment difference therefore cannot be drawn from the endpoint description.

The registry record does not report a statistical analysis plan, the sample-size justification, interim-analysis procedures, or multiplicity methods. It lists 10 outcome measures and 88 analyses, and includes outcomes at multiple thresholds and visits. Without the analysis plan, it is not possible to determine which secondary comparisons were prespecified or how repeated testing was addressed.

Missing-data handling is not reported. The record also does not give the denominators or detailed analysis populations for each outcome beyond the primary population label. The operational definition of treatable warts and the rules for evaluating complete clearance are not reported in the information. These omissions limit assessment of how consistently the endpoint was measured and how unavailable assessments might affect the estimates.

The enrollment field records 105, while the brief summary describes approximately 108 subjects. The registry record does not explain the difference. It also does not report allocation ratios or group-specific primary analysis sizes. The safety information is descriptive and lacks details about serious-event definitions, collection windows, and the denominator for the listed serious-event term percentages. These limitations constrain both efficacy and safety interpretation without demonstrating that any particular result is biased.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: A Placebo-Controlled Study Using VP-102 in the Treatment of External Genital Warts — NCT03981822.
• Registry record last updated 2024-11-27; status last verified 2021-08.
• Results first posted 2021-09-22.
• 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

The registry describes a completed, randomized, parallel-group Phase 2, double-blind, placebo-controlled study of VP-102 for external genital warts, with quadruple masking recorded. Enrollment is listed as 105. Part A evaluated 2-hour, 6-hour, and 24-hour exposure schedules; Part B included 6-hour and 24-hour schedules. Applications were scheduled every 21 days for 4 treatments.

The primary endpoint was complete clearance of all treatable warts at the Day 84 end-of-treatment visit. The primary population is described as the Part B and Part A intent-to-treat population, with Part B pooled with its respective Part A treatments. Secondary outcomes include other clearance thresholds, wart-count changes, and later assessments. The record lists 10 outcome measures and 88 analyses.

Serious adverse event counts and deaths are reported by group, but the primary comparative outcome result and several analysis details are not reported in the registry record. The brief summary’s approximate enrollment description differs from the enrollment field, without an explanation in the record.