The Purpose of the Study is to Evaluate the Effect of Ruxolitinib Cream on Itch in Participants With Atopic Dermatitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Purpose of the Study is to Evaluate the Effect of Ruxolitinib Cream on Itch in Participants With Atopic Dermatitis (NCT04839380), a na phase 2 study. The primary outcome is Change From Baseline in the Peak-Pruritus Numerical Rating Scale (PP-NRS) Score at Day 2 (24-hour Recall Period After First Application).

2. Clinical Question

3. Trial Design

This was a Phase 2, open-label, single-arm study of ruxolitinib cream in adults with atopic dermatitis. The registry lists the study status as completed, an enrollment of 49, and Incyte Corporation as sponsor. The recorded start date was 2021-10-12, and the primary completion date was 2022-11-18. Ruxolitinib cream 1.5% was applied twice daily as a thin film.

Because there was a single treatment group and no masking, participants and study personnel were not blinded to the intervention. The allocation field is listed as not applicable, consistent with the absence of a randomized comparison. The design can describe the course of measured itch scores among participants with available assessments, but does not provide a concurrent control group for estimating what would have happened over the same period without the intervention.

The primary outcome was change from baseline in PP-NRS score at Day 2, using a 24-hour recall period after the first application. Secondary outcomes included itch-score changes and thresholds for improvement at specified post-dose times on Day 1 and over later days. The listed assessment periods include Day 2 through Day 29 for some outcomes and Day 3 through Day 29 for another. Those planned outcome definitions do not establish that results for those outcomes were reported.

The registry record does not report a protocol-level sample-size justification, a statistical analysis plan, or interim analyses. It also does not report primary-outcome estimates or analysis results. Accordingly, the study's design and outcome definitions can be described, but its primary statistical finding cannot be reconstructed from 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:

Analysis population for the primary outcome, as defined in the registry: Modified Intent-to Treat (mITT) Population: all participants who had both a Baseline and at least 1 post-Baseline PP-NRS or modified PP-NRS (mPP-NRS) assessment within the treatment period. Only participants with available data were analyzed.

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 Change From Baseline in the Peak-Pruritus Numerical Rating Scale (PP-NRS) Score at Day 2 (24-hour Recall Period After First Application), measured over Baseline; Day 2.

The primary endpoint was change from baseline in the Peak-Pruritus Numerical Rating Scale (PP-NRS) score at Day 2, covering the 24-hour recall period after the first application. The scale asks participants to rate their itch at its worst during the previous 24 hours, from 0 for no itch to 10 for the worst itch imaginable. A change score is defined as the post-baseline value minus the baseline value. Under that convention, a lower post-baseline score than baseline would produce a negative change, but the registry record does not report the observed change.

Baseline was defined as the average of all non-missing PP-NRS scores recorded during the 7-day run-in period. This uses repeated pre-treatment ratings rather than relying on a single baseline report. The endpoint therefore represents a comparison between that baseline average and the Day 2 score, with the stated recall period.

Itch is a patient-reported experience, so a rating scale allows participants to express its intensity in a standardized form and makes change over time measurable. The mean change summarizes the average score change in the analyzed population. The standard deviation describes variability in individual scores around that mean; it is not itself a measure of how precisely the mean is estimated. The registry record names the mean and standard deviation as the summary measures, but does not report their values or a confidence interval. The size and precision of the primary endpoint result are therefore not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record specifies a continuous primary outcome summarized as a mean and standard deviation. It defines a within-participant score change, the assessment time, and the analysis population. It does not report the resulting estimate or a statistical analysis plan. The following explains the statistical concepts relevant to those definitions without assuming methods that are not reported.

What does a mean change represent?

A mean change is the average of participants' individual changes between the baseline measurement and the later assessment. Here, change was defined as the post-baseline score minus the baseline score. The sign follows that subtraction order: a later score below baseline produces a negative change, while a later score above baseline produces a positive change. The mean summarizes the group, but does not imply that every participant changed in the same direction or by the same amount.

A change score is different from reporting only the average score at follow-up. It uses each participant's baseline value in defining that participant's change. The registry record identifies the mean as the primary summary measure, but does not report the mean change or any baseline or follow-up mean values. No numerical description of the observed change can therefore be made.

What does the standard deviation describe?

The standard deviation describes how dispersed participant measurements are around the mean. A larger standard deviation indicates greater spread in those measurements; it does not directly state how precisely the mean is estimated. Precision also depends on the amount of usable information and the analysis method. The registry record names the standard deviation as the measure of dispersion but does not report its value.

A confidence interval is a general way to communicate uncertainty in an estimated mean or mean change. It gives a range produced by a statistical procedure, with coverage properties under that procedure's assumptions. It is not a range containing a specified proportion of individual participant outcomes. No confidence interval is reported for the primary endpoint in the registry record, so readers cannot use one to judge the estimate's precision.

How should the rating scale be read?

The PP-NRS records participants' reported worst itch over the previous 24 hours, using a scale from 0 to 10. The endpoints are anchored as no itch and the worst itch imaginable. Ratings are subjective reports, but using a consistent question and response scale enables change to be described in a standardized way. The scale's numerical format does not remove uncertainty in how an individual interprets or recalls symptoms.

The baseline value was defined as the average of all non-missing PP-NRS scores in the 7-day run-in period. Averaging repeated baseline observations can represent the pre-treatment period using more than one report. The record does not state how many baseline observations each participant contributed or how missing baseline reports were handled beyond defining the average over non-missing scores.

What does the analysis population mean?

The modified Intent-to-Treat population included participants who had both a baseline score and at least one post-baseline PP-NRS or modified PP-NRS assessment within the treatment period. The record says only participants with available data were analyzed. This is an eligibility definition for the analysis population, not an assertion that every enrolled participant contributed to the primary endpoint. The actual number analyzed is not reported in the registry record.

When outcomes are unavailable for some participants, the analyzed group may differ from the enrolled group. This is a general concern because missingness can affect the estimate if availability is related to symptoms, treatment experience, or other participant characteristics. The registry record does not report a missing-data method, an imputation procedure, or sensitivity analyses, so it is not possible to assess how missing outcome data were addressed.

What does the single-arm design allow?

In a single-arm study, the measured change is a within-group description over time. Without a concurrent comparator, the design does not estimate a difference between the intervention group and a group treated differently under the same study conditions. In general, changes in a single group may reflect multiple influences, including natural symptom fluctuation, expectations, measurement variation, and events occurring during follow-up. These considerations apply even if a change is statistically distinguishable from no change.

Open-label status means the study was not masked. Knowledge of the intervention can be relevant when outcomes are self-reported, because expectations may influence reporting. This is a general methodological consideration, not evidence that any particular rating was biased in this study.

What can be said about testing and planning?

The record does not report a statistical test for the primary endpoint, a significance level for the primary analysis, or an analysis plan. It also does not report interim analyses or a sample-size justification for the trial. Those details should not be inferred from the fact that the study was Phase 2 or from the listed enrollment.

In general, a significance test evaluates data against a specified statistical model and null hypothesis. A p-value is not an estimate of effect size and does not measure the probability that a treatment works. Since no primary test result is reported, no test-based interpretation is possible.

Planning calculations based on an observed effect are illustrations of how a future study might be sized under specified assumptions; they are not observed power and do not show that the present trial was designed with those assumptions. The record describes planning assumptions including a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Those assumptions concern planning illustrations, not evidence that this single-arm study used a two-arm design or that its own sample-size rationale is known.

Finally, the registry lists 13 outcome measures and 0 analyses. The existence of several outcome definitions does not reveal whether or how statistical multiplicity was handled. Without reported analysis methods and results, readers cannot assess testing procedures, adjustment choices, or the robustness of findings across endpoints.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 13 outcome measures, including the primary Day 2 mean-change endpoint and secondary outcomes involving other itch-rating times and improvement thresholds. It lists 0 analyses. Thus, outcome definitions are available, but statistical analysis results and the methods used to analyze them are not reported in the registry record.

When a study evaluates several outcomes or several time points, the chance of observing an apparently notable result somewhere among them can increase. This is the general issue of multiplicity. Researchers may address it through prespecified outcome hierarchies, adjustments to statistical testing, or other strategies. The registry record does not report whether any such approach was used, so no multiplicity adjustment should be assumed. The primary endpoint is identified in the record, but that alone does not establish the full testing strategy.

The primary analysis population required a baseline assessment and at least one post-baseline PP-NRS or modified PP-NRS assessment during treatment. The record states that only participants with available data were analyzed. It does not report how many participants met the primary analysis definition, the amount or pattern of missing outcome data, or whether missing values were imputed. A specific missing-data approach, including complete-case analysis or sensitivity analysis, is not reported in the registry record.

The distinction between enrolled participants and those contributing to an endpoint is important. Enrollment was 49, while the primary population definition depends on availability of assessments. The record does not provide the primary endpoint denominator, so enrollment cannot be assumed to equal the analysis population. It also does not report an analysis plan, interim analyses, or a sample-size justification for the trial.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry record lists 49 participants at risk for serious adverse events and 0 participants affected by serious adverse events in the Ruxolitinib 1.5% Cream BID group. It also reports 0 deaths. For other adverse events, 49 participants were listed at risk and 15 were affected. These are the posted counts; no percentages or comparative safety estimates are reported in the record.

Serious adverse events and other adverse events are separate categories in the registry summary. The count of 0 serious adverse events should not be read as 0 adverse events of every kind, since the record separately lists 15 participants with other adverse events. The registry's list of top serious-event terms is empty. The record does not provide enough detail to characterize the types, timing, severity, or relatedness of the other events.

These figures describe the study group and do not provide a controlled comparison. In a single-arm study, the counts cannot establish how adverse-event experience differed from what would have occurred under another treatment or no treatment. The registry record also does not provide additional context such as exposure-adjusted rates or a detailed event narrative. The counts should therefore be read as the reported safety summary, not as proof that an event is impossible or that risk is absent.

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

The record establishes that the study examined itch ratings in adults with atopic dermatitis after use of ruxolitinib cream 1.5%, applied twice daily. It defines a primary outcome based on change in the mean PP-NRS score from baseline to Day 2, and describes how the scale and baseline were constructed. It also lists secondary itch outcomes and a safety summary.

What the record does not establish is the observed primary change. The mean, standard deviation, confidence interval, and statistical test result are not reported in the registry record. Consequently, the direction and size of the primary outcome, and the uncertainty around it, cannot be characterized from this entry. Secondary outcome definitions are also not outcome findings; their results are not reported in the registry record.

The single-arm, open-label design is important to what any within-group change could mean. A change between baseline and follow-up would describe the participants' scores over time, but without a concurrent comparison group it would not isolate the effect of the intervention. This is a general limitation of before-and-after comparisons, especially for a subjective, self-reported outcome that may vary over time.

The enrollment of 49 is not necessarily the number included in the primary analysis. The analysis population required both baseline and at least one post-baseline assessment, and the record says only available data were analyzed. The actual analysis count and the handling of missing outcomes are not reported in the registry record.

The appropriate conclusion is therefore limited: the registry describes a completed Phase 2 study, its intervention, design, outcome definitions, and certain safety counts, but does not report the primary efficacy result or statistical analyses. It cannot support a conclusion about the observed magnitude or precision of change, or a causal comparison with another approach.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of how endpoint definitions and design determine what can be concluded. Its primary outcome is a mean change in a patient-reported itch score, with a stated scale, recall period, baseline rule, and analysis population. Those details let readers understand what the intended measurement represents, even though the registry record does not report the numerical primary result.

The single-arm, open-label structure also illustrates the difference between describing change and attributing change. Repeated measurements can document a participant group's course over time, but the absence of a concurrent control makes causal interpretation difficult. This distinction is central in clinical research: a precisely estimated within-group change would still not, by itself, quantify a comparative treatment effect.

The record further shows why enrollment should not be confused with the denominator used for an endpoint. The primary population definition requires baseline and post-baseline observations, and the number actually analyzed is not reported. Without that information, readers cannot assess the extent to which the endpoint analysis represents the enrolled group.

Finally, the registry lists multiple outcomes while reporting no analysis results or statistical plan. This makes multiplicity, missing-data handling, and the relationship between planned outcomes and reported findings impossible to evaluate. The trial matters statistically not because the registry entry supplies a complete efficacy analysis, but because it demonstrates the limits of interpreting outcome definitions, design labels, and enrollment counts in the absence of the corresponding estimates and methods.

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 central limitation of the registry record for statistical interpretation is that it does not report the primary outcome result. The mean change in PP-NRS score, its standard deviation, any confidence interval, and any statistical test result are not reported in the registry record. Results for the listed secondary outcomes are also not reported. This prevents assessment of the observed effect's direction, size, and precision.

The open-label, single-arm design has no randomized or concurrent comparison group. Any within-group change would not, on its own, distinguish an intervention-associated change from natural fluctuation, expectations, measurement variation, or other influences over time. This matters particularly because the primary endpoint relies on participants' reports of itch.

The record reports enrollment of 49, but the primary analysis population required both baseline and post-baseline ratings. The number included in the primary analysis is not reported in the registry record. The amount and pattern of missing data, the approach to missing observations, and any sensitivity analyses are also not reported.

The registry lists 13 outcome measures but 0 analyses. It does not report a statistical analysis plan, multiplicity procedures, interim analyses, or the trial's sample-size justification. The summary therefore does not establish how the outcomes were analyzed or how uncertainty and multiple outcomes were addressed. These limitations are specific to the information recorded and the study design; they do not establish that unreported analyses or procedures were absent from other study documents.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: The Purpose of the Study is to Evaluate the Effect of Ruxolitinib Cream on Itch in Participants With Atopic Dermatitis — NCT04839380.
• Registry record last updated 2023-10-31; status last verified 2023-10.
• Results first posted 2023-10-31.
• 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

This completed Phase 2 study was open-label and single-arm, and enrolled 49 adults with atopic dermatitis. Ruxolitinib cream 1.5% was applied twice daily as a thin film. The study's primary outcome was mean change from baseline in PP-NRS score at Day 2, based on a 24-hour recall period after the first application. The scale ranged from 0 for no itch to 10 for the worst itch imaginable.

The primary analysis population required baseline and at least one post-baseline itch assessment, with only available data analyzed. The registry record does not report the primary outcome estimate, its dispersion, a confidence interval, or statistical analyses. It lists 13 outcome measures and 0 analyses. For safety, the record lists 0 participants with serious adverse events, 15 with other adverse events, and 0 deaths among the reported group.