Healing Effects of HP802-247 Versus Antibiotic Ointment in Mohs Micrographic Surgery Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Healing Effects of HP802-247 Versus Antibiotic Ointment in Mohs Micrographic Surgery Patients (NCT01359735), a randomized phase 2 study. The primary outcome is The Primary Efficacy Measure Was the Investigator's Global Assessment of Healing (IGAH)..

2. Clinical Question

3. Trial Design

This was a phase II randomized, open-label study with a parallel-group design. It compared HP802-247 with bacitracin ointment for healing after Mohs micrographic surgery in patients with non-melanoma skin cancer. The registry record lists 8 participants as enrolled and marks the study completed. The listed study start was 2011-05 and the primary completion was 2011-11.

In the HP802-247 arm, the intervention is described as allogeneic, growth-arrested keratinocytes and fibroblasts, at a final concentration of 5.0 M cells/mL with a 1:9 keratinocyte-to-fibroblast ratio, applied weekly. The comparison arm received bacitracin antibiotic ointment. Since the study was open-label and masking was listed as none, the registry record does not describe blinding of participants or investigators. It does not report how randomization was carried out, whether allocation was concealed, or the treatment schedule for the ointment.

The primary measure was the Investigator’s Global Assessment of Healing, assessed at study Weeks 4 and 13. The registry record says descriptive statistics were summarized for the measure as both a continuous and a categorical variable, by treatment week and treatment endpoint. The listed secondary outcomes include complete wound closure at each evaluation visit, time in days to wound closure, and investigator-reported and subject-reported signs and symptoms.

The registry record identifies the ITT population as all subjects who underwent MMS. It does not report how many randomized participants underwent surgery, whether any participants did not receive their assigned treatment, or how many contributed data at each visit. Thus, enrollment describes the overall study size, but does not establish the number included in each specific efficacy analysis.

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: Subjects who met inclusion criteria returned for visit1 on the day of surgery and entered the study following. Subjects randomly assigned to HP802-247 or Bacitracin for post-surgical treatment, which lasted for up to 12 weeks or wound closure, which ever occurred first. Following completion of treatment subjects were followed for 4 weeks

Overall Study

Analysis population for the primary outcome, as defined in the registry: The ITT population - all subjects who underwent MMS.

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 The Primary Efficacy Measure Was the Investigator's Global Assessment of Healing (IGAH)., measured over 13 weeks- The IGAH was measured at study Weeks 4 and 13.

The primary efficacy measure was the Investigator’s Global Assessment of Healing (IGAH). This is described as a four-point scale: 0 means not effective, 1 means slightly effective, 2 means moderately effective, and 3 means very effective. The scale is an investigator assessment of wound healing, rather than a direct measurement of wound dimensions or time to closure.

The registry record says IGAH was assessed at study Weeks 4 and 13. It also says descriptive statistics were summarized both for IGAH as a continuous variable and as a categorical variable, by treatment week and treatment endpoint. That approach can present the distribution of scores in more than one way: a continuous summary describes scores numerically, while a categorical summary retains the distinct scale categories. Because the scale has only four ordered levels, the categories convey the difference between levels without implying that the distance from one level to the next is necessarily equal.

An investigator-rated healing measure is used to capture a clinical judgment about the wound’s status at an assessment visit. Comparing scores at specified visits can describe how ratings differ between treatment groups at those points in follow-up. The listed secondary outcomes address other aspects of healing, including complete wound closure and time to closure, as well as reported signs and symptoms. Those outcomes do not replace the primary measure. The registry record does not report the IGAH values or comparative estimates, so the direction and magnitude of any difference cannot be described.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes the endpoint, summaries, and comparison method, but does not report the numerical analysis results. The explanations below distinguish the stated methods from general statistical considerations.

What does the Wilcoxon rank-sum test compare?

The stated comparison for IGAH was the Wilcoxon rank-sum test. In general, this method ranks observed values across two independent groups and compares how those ranks are distributed between groups. It does not require the outcome to follow a normal distribution in the way a conventional two-sample t-test does. It can be useful when the outcome is ordinal or when distributional assumptions for a mean-based test are not appropriate.

The test is not simply a test of whether two group means are different. Its result reflects the relative ordering of observations across the groups. A location-shift interpretation requires additional assumptions about the shapes of the group distributions. The IGAH is an ordered scale with four categories, so the rank-based method uses the order of the categories. It does not make the gaps between adjacent categories numerically equal. The registry record does not report the observed ranks, test statistics, or p-values, so the result of this test cannot be reconstructed or interpreted.

Why report both continuous and categorical summaries?

The registry record says IGAH was summarized both as a continuous variable and as a categorical variable. In general, a numerical summary can offer a compact description of scores, while category-specific counts or summaries make the distribution across the scale levels visible. For an ordered scale, retaining category information can be especially useful because it avoids treating the score as if every step had a known, equal distance. No specific group summaries are reported in the registry record, so there is no basis for describing the pattern of scores under either representation.

What does a one-sided test mean?

The record states that a one-sided p-value was reported because the study was small and exploratory. In general, a one-sided test evaluates evidence for an effect in a prespecified direction. A two-sided test evaluates evidence for a difference in either direction. The choice affects the interpretation of a p-value and should be tied to a direction specified before examining the results. The record does not report the direction, the p-values, or any protocol details about how the test direction was selected. The stated use of one-sided testing should therefore be described, but cannot be independently evaluated from the available information.

A p-value, in general, measures how unusual the observed data or more extreme data would be under a specified statistical model and a null hypothesis. It is not the probability that the null hypothesis is true, and it does not measure the size or clinical importance of a difference. A confidence interval, in general, expresses the range of effect estimates compatible with the data and a specified confidence procedure. The registry record does not report confidence intervals or primary p-values, so neither the evidence against a null comparison nor the precision of an effect estimate can be assessed.

How should the repeated assessment visits be understood?

IGAH was measured at Weeks 4 and 13, and comparisons were described for each treatment week and treatment endpoint. These are assessments at more than one time point. In general, outcomes measured repeatedly in the same participant are correlated: observations from one participant are not necessarily independent of one another. The registry record describes a Wilcoxon rank-sum test for each treatment week and endpoint, but does not report whether a repeated-measures model or another approach was used to account for within-participant correlation across visits. A rank-sum comparison at an individual visit compares groups at that visit; it does not, by itself, estimate a treatment-by-time pattern.

Multiple time points and endpoints also raise the general issue of multiplicity. When several statistical tests are performed, the chance of obtaining at least one apparently notable result can increase if all tests are treated as independent opportunities for discovery. The registry record does not report a multiplicity adjustment, a hierarchy of outcomes, or a prespecified strategy for interpreting results across visits and outcomes. Because the numerical results are not reported, it is not possible to assess how any multiplicity strategy affected the findings.

What does a small sample mean for statistical precision?

In general, a small study tends to provide less information for estimating treatment differences than a larger study, so confidence intervals can be wide and results can be sensitive to individual observations. The total enrollment was 8. The safety summary lists 4 participants at risk in each group, but the registry record does not state the number contributing to each primary efficacy analysis or visit. The endpoint’s distribution across its four categories is also not reported.

The registry record does not report a trial sample-size justification. It includes no stated target effect or planned precision in the registry record for this analysis. Any sample-size planning illustration based on an observed effect would be a hypothetical planning exercise, not an observed trial result or a measure of the trial’s achieved power. No such numeric planning estimates are reported in the registry record.

In general, over-dispersion means that variability in observed data is greater than a model assumes. Accounting for it can be important for some outcome models because underestimated variability may make standard errors too small and intervals too narrow. The primary comparison is described as a rank-sum test, and the registry record does not report an over-dispersion assessment or model-based variance estimates. The record also does not describe any model for the secondary outcomes.

These general principles explain how to read the methods, not what the results were. The registry record reports a study design and an analysis description, but the numerical primary outcome findings and their precision are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The primary endpoint was assessed at study Weeks 4 and 13, with descriptive summaries by treatment week and treatment endpoint. The registry record describes a Wilcoxon rank-sum test for each treatment week and treatment endpoint. It also lists multiple secondary outcomes: complete wound closure at each evaluation visit, time in days to wound closure, and investigator-reported and subject-reported signs and symptoms. These multiple assessments create several potential comparisons.

In general, multiplicity matters because the chance of at least one apparently unusual result can rise when many tests are conducted. A prespecified hierarchy, adjustment, or clear separation of confirmatory and exploratory outcomes can help frame interpretation. The registry record does not report a multiplicity adjustment, a testing hierarchy, or a plan for interpreting the collection of outcomes. Since the numerical outcome results are not reported, it is not possible to tell whether multiplicity affected any conclusions.

Missing-data methods are also not reported in the registry record. The record defines the ITT population as all subjects who underwent MMS, but does not state how missing IGAH assessments, withdrawals, or participants without a visit measurement were handled. It does not report the number analyzed at each visit or whether imputation was used. This is distinct from saying that data were missing: the registry record simply does not describe their availability or handling.

The record does not report details of the randomization process, protocol deviations, analysis exclusions, or a sensitivity analysis. It also does not give a sample-size justification. These omissions limit assessment of how closely the reported analysis, if available, would reflect the planned comparison and how robust it would be to alternative assumptions. The definition of the ITT population is useful, but does not by itself explain how the population was implemented for each endpoint and visit.

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.

Most frequent non-serious adverse event terms

The registry safety summary lists 4 participants at risk in the HP802-247 group and 4 in the bacitracin ointment group. It reports 0 serious adverse events in each group. Other adverse events are listed for 2 participants in the HP802-247 group and 3 in the bacitracin ointment group. These are participant counts, not event counts, and the registry record does not name the other adverse events in the registry record for this analysis.

In general, an adverse event is an event recorded during a study; a count alone does not establish that the study treatment caused it. The summary does not describe event severity apart from the serious-event category, timing, duration, relationship to treatment, or whether participants experienced more than one event. The registry record also does not report deaths as a numerical finding in the available safety summary.

The small number of participants at risk is important for interpretation. Zero recorded serious adverse events in these groups does not establish that serious events cannot occur, and the other-event counts do not give a precise estimate of how frequently such events would occur in a broader population. The figures should be read as the reported safety observations within this trial, not as a definitive comparison of safety between treatments.

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

This record describes a randomized comparison of HP802-247 and bacitracin ointment after Mohs micrographic surgery, with IGAH as the primary efficacy measure. It specifies a four-point scale and assessments at Weeks 4 and 13, and it names a rank-based comparison method. Those details make the intended clinical question and the general form of the analysis understandable.

The registry record does not report the primary scores, group summaries, estimated treatment difference, test statistics, p-values, or confidence intervals. Consequently, it does not show whether healing assessments differed between groups, in which direction they may have differed, or how precise any difference was. A result cannot be inferred from the study title, the intervention descriptions, or the fact that the study was completed.

Likewise, the listed secondary outcomes do not establish that wounds closed, how long closure took, or what signs and symptoms were reported. Their numerical results are not reported in the registry record. The safety summary does report no serious adverse events in either group and other adverse events for 2 participants in the HP802-247 group and 3 in the bacitracin ointment group. These observations describe the recorded counts in a small trial; they do not establish causation or rule out uncommon harms.

In general, a clinical trial result is best understood through an effect estimate, its uncertainty, the analysis population, and the outcome measurement context, alongside the design and limitations. Here, the design and some methods are described, but the efficacy estimates and their uncertainty are not. The statistical interpretation is therefore constrained to explaining what was planned and what the safety counts record. No conclusion about comparative efficacy or the broader performance of either treatment follows from the available registry entries alone.

13. Why This Trial Matters Statistically

This trial is statistically notable because it combines a small enrollment with an ordinal primary measure and more than one assessment time. The registry record lists 8 participants and identifies IGAH, a four-point investigator-rated scale, as the primary efficacy measure. It also specifies assessments at Weeks 4 and 13. These details make clear why it is important to distinguish a score’s ordering from an assumption that the distance between each adjacent score is equal.

The stated use of the Wilcoxon rank-sum test is a recognizable rank-based approach for comparing two groups. The record also says descriptive statistics were summarized for IGAH both continuously and categorically. Together, these method descriptions illustrate how the choice of analysis and presentation can reflect the structure of an outcome. However, without scores or estimates, readers cannot judge the actual distribution or the magnitude and precision of any group difference.

The study also illustrates why a design description and a result are not interchangeable. Randomization can support a fair comparison when carried out and analyzed appropriately, but the registry record does not detail the randomization procedure, analysis counts by visit, or missing-data handling. Its open-label status is relevant context for an investigator-rated endpoint, while the record does not report whether any other safeguards were used. These are questions about how to interpret a result, not grounds for assuming a particular bias.

Finally, the safety counts show how sparse observations constrain interpretation. The registry summary records no serious adverse events among 4 participants at risk in each group, alongside other adverse-event counts. Such a record can describe what was observed in the trial, but cannot provide high precision about uncommon outcomes. The study is a useful example of why method transparency, numerical effect estimates, and uncertainty are all needed for statistical interpretation.

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 most important limitation of the available record for statistical interpretation is that it does not report the primary efficacy results. IGAH scores, group summaries, comparative estimates, test statistics, p-values, and confidence intervals are not reported in the registry record. Without these, neither the magnitude nor the precision of the primary comparison can be assessed.

Enrollment was 8, which leaves little information for evaluating differences across the four IGAH categories or for characterizing uncommon safety events. The registry record lists 4 participants at risk in each safety group, but does not report the number contributing to the primary analysis at Weeks 4 and 13. It does not describe missing assessments, withdrawals, protocol deviations, or how the ITT definition was applied to each outcome.

The design was open-label, with masking listed as none. Because the primary measure was investigator-rated, lack of masking is relevant context when interpreting the outcome assessment. The registry record does not report whether outcome assessors were otherwise separated from treatment delivery or whether other procedures were used to reduce assessment bias. No inference about the presence or size of bias can be made from that absence of detail alone.

The statistical description reports one-sided testing but does not state the direction of the test. It also does not report a multiplicity strategy for assessments at multiple visits and treatment endpoints, or for the listed secondary outcomes. The randomization procedure, sample-size justification, and missing-data methods are not reported in the registry record. These limitations restrict evaluation of the analysis plan and make it especially important not to treat the outcome definitions or safety counts as evidence of comparative efficacy.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Healing Effects of HP802-247 Versus Antibiotic Ointment in Mohs Micrographic Surgery Patients — NCT01359735.
• Registry record last updated 2017-06-29; status last verified 2017-05.
• Results first posted 2017-06-29.
• 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 record describes a completed, randomized, open-label, parallel-group phase II study of HP802-247 versus bacitracin ointment for healing after Mohs micrographic surgery in people with non-melanoma skin cancer. Enrollment was 8; the listed study start was 2011-05 and primary completion was 2011-11.

The primary measure was the Investigator’s Global Assessment of Healing, a four-point scale assessed at Weeks 4 and 13. The stated comparison was a one-sided Wilcoxon rank-sum test, with descriptive summaries for IGAH as a continuous and categorical variable. The registry record does not report the numerical primary efficacy results or their precision.

The safety summary lists 0 serious adverse events among 4 participants at risk in each group. Other adverse events were recorded for 2 participants in the HP802-247 group and 3 in the bacitracin ointment group. The record does not report sufficient efficacy results, analysis details, or event descriptions to support broader conclusions about comparative outcomes.