Aczone Gel 7.5% in the Treatment of Acne Vulgaris in Patients With Skin of Color: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Aczone Gel 7.5% in the Treatment of Acne Vulgaris in Patients With Skin of Color (NCT03681470), a na phase 4 study. The primary outcome is Mean Change From Baseline to Week 12 in Global Acne Assessment Score (GAAS).

2. Clinical Question

The study is titled as an investigation of efficacy and tolerability in people with skin of color. Its summary also describes an interest in facial hyperpigmentation and post-inflammatory hyperpigmentation. The listed secondary outcomes include GAAS at additional visits, hyperpigmentation measures, a target-lesion melanin measure, dark-spot scores, counts of participants meeting specified GAAS categories, and changes in lesion counts.

Those aims describe what the study set out to examine, not what its results establish. Without a reported primary endpoint estimate, readers cannot determine the observed average change in GAAS from the registry record. Without a separate comparison group, changes over time cannot be separated from other possible explanations, such as the natural course of acne or changes in other care. The record supports describing the study question and design, but not a controlled estimate of treatment effect.

3. Trial Design

This is a Phase 4, open-label, single-group study of Aczone Gel 7.5% in patients with acne vulgaris and skin of color. The registry lists an enrollment of 20 and the study status as completed. The recorded start date is 2019-04-09, and the primary completion date is 2021-05-06. The sponsor is Icahn School of Medicine at Mount Sinai.

Single-group means the record describes one group receiving the intervention, rather than distinct treatment and control groups. Allocation is recorded as not applicable, and masking is listed as none. Participants and investigators were therefore not masked according to the registry entry. The record does not describe a randomization procedure, and its own design classification is not a randomized comparison.

The primary endpoint is mean change in GAAS from baseline to Week 12. Other listed outcomes include GAAS at Week 4, Week 18 and Week 24; changes in the Post Acne Hyperpigmentation Index and target-lesion Melanin Index at later visits; dark-spot and GAAS category counts; and percent changes in lesion counts. The summary also states that facial hyperpigmentation and post-inflammatory hyperpigmentation were of interest.

The registry record does not report the treatment duration, the detailed visit schedule beyond the stated outcome time points, adherence, concomitant treatments, eligibility criteria, or the number of participants assessed at each visit. It also does not report participant demographics or the characteristics of acne at baseline. These omissions limit how fully the enrolled group and conduct of the study can be described.

A single-group before-and-after design can describe recorded changes during follow-up, but it cannot by itself show how those changes compare with what would have happened without the intervention. Open-label assessment can also be vulnerable to expectations or differences in scoring. These are general design considerations, not claims about what occurred in this study.

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.

6. Primary Endpoint

The registry lists the primary outcome as Mean Change From Baseline to Week 12 in Global Acne Assessment Score (GAAS), measured over baseline and week 12.

The primary endpoint is the mean change from baseline to Week 12 in Global Acne Assessment Score. GAAS is a five-point scale running from 0, “None,” to 4, “Severe.” Its descriptions distinguish levels of facial acne using the presence and amount of noninflammatory lesions, inflammatory lesions, and nodulo-cystic lesions. A lower score corresponds to a less severe category on the scale; a change in score describes movement in the recorded assessment, not by itself the cause of that movement.

A mean change summarizes the average within-participant difference between the baseline and follow-up scores among the participants included in the analysis. The registry identifies standard deviation as the measure of dispersion. In general, a standard deviation describes how spread out individual values are around their mean; it does not show the uncertainty of the mean in the same way as a confidence interval.

GAAS is used as a clinical severity measure because it condenses an assessment of acne into an ordered score that can be compared across visits. That convenience comes with limits: the scale is categorical in its descriptions, while a mean treats score steps as suitable for averaging. Interpretation therefore depends on the scale and assessment being applied consistently. The registry record does not report the Week 12 mean change or standard deviation, so the size and variability of the observed change cannot be described from this record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary measure as a mean change in a continuous measure and identifies standard deviation as its dispersion statistic. The endpoint is a change in GAAS between baseline and Week 12. A change score is calculated for each participant with measurements at the relevant visits, and the mean summarizes those participant-level changes. The registry record does not provide the actual mean or standard deviation.

What does a mean change describe?

In general, a mean change is an average of individual changes, not a count of participants who improved and not a measure of how many reached a particular score. Opposing individual changes can be concealed by an average, so a mean is best read alongside information about variability and the number of participants contributing data. The registry identifies standard deviation for variability, but does not report that value or the endpoint analysis sample size.

GAAS is described as a five-point scale, with categories from no evidence of facial acne to severe acne. Its categories are ordered, but the wording of adjacent categories does not establish that each step represents the same clinical distance. Treating the scale numerically and averaging scores is a common summary approach, but interpretation should remain anchored to the category definitions. The record does not report whether any additional analysis of the ordered categories was conducted.

What does a confidence interval add?

In general, a confidence interval expresses the statistical uncertainty around an estimate under the assumptions of the analysis. It is not a guarantee that the true value lies within a particular interval, and its interpretation depends on the method and data. A narrow interval generally indicates greater precision than a wide interval, while the interval’s position relative to no change can inform whether the data are compatible with a range of effects. No confidence interval for the primary endpoint is reported in the registry record, so precision cannot be assessed.

What can a p-value establish?

In general, a p-value measures how unusual data at least as incompatible with a specified null hypothesis would be if that hypothesis and the analysis assumptions held. It does not measure the probability that a treatment works, the size of an effect, or its importance. The registry record does not report a primary endpoint p-value or the hypothesis-testing procedure. A p-value would not resolve the absence of a control group: statistical evidence of change from baseline would still not isolate why the change occurred.

Why does the single-group design matter?

With a separate comparator group, a treatment comparison can account for changes that may occur over time in both groups, subject to the design and analysis assumptions. Here the registry classifies the study as single-group and lists no masking. General concerns for an unmasked before-and-after assessment include expectation effects and variation in how an outcome is scored. No conclusion that these biases occurred is warranted, but the design cannot rule them out through a randomized, masked comparison.

How should planning calculations be read?

General sample-size calculations estimate the number of participants needed for a planned statistical comparison under stated assumptions. The planning illustration described for this analysis uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; it defines the effect to detect as a stated fraction of the observed effect. For non-time-to-event outcomes, such illustrations are expressed as participants per arm. This is a hypothetical two-arm planning framework, not the actual single-group design recorded for this study.

Such calculations are planning illustrations, not observed power and not evidence that the study detected an effect. They depend on assumptions about the effect size and variability, among other features of the method. The registry record does not report a protocol-based sample-size justification, and the planning illustration does not substitute for one. No numerical planning results need be interpreted as outcomes observed among study participants.

What does over-dispersion mean?

In general, over-dispersion occurs when data vary more than a statistical model assumes. It can make standard errors too small and confidence intervals too narrow if the extra variation is ignored. This is especially relevant to some count outcomes, such as lesion counts, where a simple model may not capture their variability. The registry record does not report a model for lesion counts or whether over-dispersion was assessed. This general issue should not be mistaken for a finding about these data.

The registry record lists 0 analyses. It does not report a statistical analysis plan, adjustment covariates, handling of repeated measurements, missing-data approach, or analysis populations. The outcome descriptions alone do not establish which statistical models or tests were applied.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Patients With Acne Vulgaris")
n   <- c(12)
m   <- c(-0.86)
sp  <- c(0.66)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Patients With Acne Vulgaris  12  -0.860  0.660  -1.279  -0.441

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary GAAS change endpoint and multiple secondary outcomes covering acne severity, hyperpigmentation, dark-spot scores, and lesion counts at several follow-up times. When several outcomes or time points are tested, the chance of at least one apparently notable result can increase if each test is treated independently. In general, multiplicity procedures can control or otherwise address that issue, but they involve choices about which comparisons belong together and what error rate is of interest. A multiplicity adjustment or prespecified testing hierarchy is not reported in the registry record.

The record does not report the statistical analysis plan, so it is not possible to determine how outcome selection, repeated assessments, or subgroup analyses were intended to be handled. The registry identifies the primary endpoint, but does not state whether other analyses were confirmatory or exploratory. The record lists 0 analyses; this describes what is listed in the registry and does not establish whether analyses were conducted outside the registry entry.

Missing-data procedures are not reported in the registry record. The record does not state how missing Week 12 measurements, withdrawals, or incomplete outcome records were handled, nor how many participants contributed to each endpoint. Enrollment of 20 therefore should not be assumed to equal the analysis population for every outcome.

The analysis population is also not reported. The record does not say whether analyses used all enrolled participants, participants who began treatment, participants with available outcome measurements, or another defined group. Without that information and the number analyzed, readers cannot assess how missing observations or exclusions may affect the results.

12. 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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for the single group titled “Patients With Acne Vulgaris.” The group lists 20 participants at risk and 0 participants affected by serious adverse events. It also lists 0 deaths. These are the registry’s recorded counts; they do not describe the primary efficacy outcome.

For other adverse events, the registry lists 20 participants at risk and 16 affected. The record does not provide the event terms in this entry, so the count should not be read as 16 distinct event types or as a description of their nature. It is a count of participants affected according to the registry’s category.

In general, an observed count of zero serious events does not establish that the risk is absent. Safety counts are interpreted in light of the number of participants observed, the duration and completeness of follow-up, event definitions, and the way events were collected. Those details are not fully reported in the registry record. The figures also do not allow comparison with another treatment or with no treatment, because the study is single-group.

The registry does not list serious adverse-event terms in the posted record. The counts should therefore be reported as recorded, without inferring the types, causes, severity of non-serious events, or a comparative safety profile.

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

The registry record establishes that a completed, open-label, single-group study enrolled 20 participants and identified mean change in GAAS from baseline to Week 12 as its primary endpoint. It also describes a set of secondary measures, including outcomes related to acne severity, hyperpigmentation, dark spots, and lesion counts. The record reports safety counts for the study group.

It does not report the primary endpoint result. Without the observed mean change, its standard deviation, or an interval estimate, the registry record cannot show the amount or precision of change in GAAS. The endpoint scale indicates that lower categories represent less severe acne, but the record does not establish whether participants’ scores moved in either direction.

The design also limits what any before-and-after result could mean. A change during follow-up would not, on its own, distinguish the effect of the intervention from other changes over time. There is no separate comparator group in the registry description, and masking is listed as none. This is a limitation on causal interpretation, not a claim that the intervention had no effect.

The safety record lists 0 participants affected by serious adverse events and 0 deaths, alongside 16 participants affected by other adverse events. These counts describe what is recorded for this group; they do not establish comparative safety or rule out events not captured in the registry.

In short, the posted information supports a description of the study question, design, endpoints, and recorded safety counts. It does not support a conclusion about the magnitude of a treatment effect, comparative benefit or harm, or the precision of the primary result. Those questions require outcome analyses and context that are not reported in the registry record.

14. Why This Trial Matters Statistically

This study addresses a population named explicitly in its title and summary: men and women with skin of color and acne vulgaris. The summary notes that the study aimed to investigate treatment effects in this population and to evaluate facial hyperpigmentation and post-inflammatory hyperpigmentation. Statistically, the focus matters because measures of acne severity and pigmentation describe different outcomes; a result on one measure cannot stand in for another.

The registry records several kinds of outcomes, including an overall acne assessment, pigmentation measures, dark-spot scores, and lesion counts. Each measure captures a different aspect of the study question and may require its own interpretation. For example, a change in an overall severity score is not interchangeable with a change in a target-lesion melanin measure. Reporting outcome-specific estimates, uncertainty, and analysis methods would help readers understand what the data address.

The study also illustrates why design and results must be read together. A single-group study can document observations across visits, while a comparator is needed to estimate how outcomes differ from another group under a defined comparison. The registry record provides no controlled contrast and does not report the primary numerical result. Statistical significance, clinical interpretation, and causal attribution cannot be inferred from the design description or completion status.

Finally, a focused population and a named set of outcomes do not remove the need for transparent reporting. Participant characteristics, analysis populations, missing-data handling, outcome estimates, and their uncertainty would help readers judge how directly the findings apply and how robust they are. Those details are not reported in the registry record. The record is therefore informative about the study’s stated aims and structure, but limited as a source of evidence about results.

15. 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 direct limitation of the registry entry is that it does not report the primary outcome result. The Week 12 mean change in GAAS and its standard deviation are not reported in the registry record, and there is no reported confidence interval or p-value. Numerical findings for the listed secondary outcomes are also not reported in the registry entry.

The study is single-group, open-label, and has no separate comparator in the registry description. This prevents a controlled comparison and leaves any recorded change open to alternative explanations. The record does not describe masking, independent outcome assessment, or safeguards against measurement variability beyond listing masking as none.

The registry does not report detailed participant characteristics, the number assessed at each visit, or the analysis population. Although enrollment is listed as 20, the record does not establish how many participants contributed to each outcome. Eligibility details, treatment adherence, concomitant care, and specific missing-data methods are also not reported in the registry record.

The analysis plan is not reported. In particular, the record does not state the statistical methods used, adjustment for multiple outcomes or time points, handling of repeated measures, or whether any covariates were considered. The registry lists 0 analyses, which is a description of the record and does not establish that no analyses were performed.

Finally, the safety entry gives counts but does not list serious adverse-event terms or provide detail about the other adverse events. Without fuller safety definitions, follow-up information, and a comparator, those counts cannot establish a comparative safety profile. These limitations concern what can be learned from the registry entry; they do not demonstrate that any particular result or event did or did not occur.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Aczone Gel 7.5% in the Treatment of Acne Vulgaris in Patients With Skin of Color — NCT03681470.
• Registry record last updated 2022-07-27; status last verified 2022-07.
• Results first posted 2022-07-27.
• 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.

19. Record Summary

The registry describes a completed Phase 4, open-label, single-group study of Aczone Gel 7.5% in acne vulgaris among people with skin of color. Enrollment is listed as 20. The sponsor is Icahn School of Medicine at Mount Sinai. The recorded study start date is 2019-04-09, and the primary completion date is 2021-05-06.

The primary endpoint is mean change in GAAS from baseline to Week 12. Secondary outcomes include additional acne-severity assessments, pigmentation measures, dark-spot scores, and lesion counts. The registry record does not report numerical results for the primary endpoint or the listed secondary outcomes, and it does not report an analysis plan or missing-data approach.

For safety, the registry lists 0 participants with serious adverse events, 0 deaths, and 16 participants with other adverse events among 20 at risk. The single-group design does not provide a like-for-like control comparison. The record therefore describes the study’s aims and structure, but does not establish a controlled treatment effect.