Open Label, Safety and Efficacy Study of Topical Investigational Drug to Treat Patients With Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Open Label, Safety and Efficacy Study of Topical Investigational Drug to Treat Patients With Psoriasis (NCT00617994), a non-randomized phase 2 study. The primary outcome is Number of Treatment of Emergent Adverse Events.

2. Clinical Question

In statistical terms, this study can describe events recorded during treatment and explore clinical outcomes within its enrolled cohorts. Because it was open-label and non-randomized, it cannot by itself separate treatment effects from differences between cohorts, changes over time, or other influences. Its primary question is about observed safety events, not a randomized estimate of comparative efficacy.

3. Trial Design

This was a completed Phase 2, open-label study of topical ruxolitinib in patients with plaque psoriasis. The registry lists non-randomized allocation, no masking, and a parallel model. Enrollment was 25. The record gives a start date of 2007-08-31 and a primary completion date of 2009-04-30.

The arm descriptions identify Groups A, B, and C by the extent of lesion involvement: Group A involved a small percent BSA, while Groups B and C involved larger BSA than the preceding cohort. The safety results are listed for Cohorts A through E. Descriptions for Cohorts D and E, and the precise BSA ranges or treatment differences between the cohorts, are not reported in the registry record. The record does not specify a comparator group; the cohorts should not be interpreted as randomized treatment arms or as a controlled comparison.

The intervention is identified as ruxolitinib, a drug, applied as a topical cream. The official title describes pharmacokinetic, pharmacodynamic, tolerability, safety, and preliminary efficacy aims. The brief summary emphasizes application to 2 - 20% BSA in patients with active, stable plaque psoriasis. Detailed dosing instructions, duration of application, and other protocol procedures are not reported in the registry record.

The record lists 7 outcome measures and identifies lesion severity, lesion area, and Physician Global Assessment as secondary outcomes. It lists 0 analyses. That registry entry does not establish whether analyses were conducted but not entered, or whether none were conducted; that context is not reported in the registry record. The available information therefore supports a description of the design and posted safety counts, but not a reconstruction of a full analysis plan or detailed efficacy assessment.

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: A total of 25 participants with active but stable plaque psoriasis were enrolled in the dose-escalation study.

Overall Study

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: The intent-to-treat (ITT) population included all enrolled participants who applied INCB018424 cream at least once and had a predose and at least one post-dose lesion assessment.

6. Primary Endpoint

The registry lists the primary outcome as Number of Treatment of Emergent Adverse Events, measured over Approximately 3 months.

The primary endpoint is the number of participants with treatment-emergent adverse events. The record defines these as events reported for the first time, or worsening of a pre-existing event, after the first dose of study drug or treatment. The timeframe is approximately 3 months, and the unit is participants.

A participant-based count addresses whether an event was experienced by participants during the specified period. It is distinct from a count of all event episodes: a participant may experience more than one event, but the endpoint concerns participants with events. The registry record does not provide enough detail to determine how recurrent events, events spanning multiple terms, or events with uncertain timing were handled in the primary endpoint analysis.

In general, safety endpoints of this kind are used to describe the types and frequency of events observed during treatment. They are important for characterizing tolerability and identifying events that may warrant closer scrutiny in later research. A count alone does not establish that treatment caused an event, because events can occur for reasons unrelated to treatment and the study has no randomized control group.

The posted safety information separates serious adverse events from other adverse events. It reports counts for these categories by cohort, but the registry record does not provide a separate, fully detailed primary endpoint analysis or a complete event-level listing in the information available. The listed lesion-severity, lesion-area, and Physician Global Assessment measures address clinical outcomes rather than the primary safety question; their numerical results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The design determines what statistical claims are justified. This trial was non-randomized and open-label. Random allocation, when used, helps balance measured and unmeasured characteristics between treatment groups on average. Without randomization, cohort membership may be related to participant characteristics or clinical features. Open-label treatment also means participants and study personnel knew treatment was being given. In general, these design features make comparisons more vulnerable to confounding and assessment effects. They do not prevent descriptive reporting, but they limit causal interpretation.

What does a participant count represent?

The primary endpoint is expressed as a count of participants with treatment-emergent adverse events, rather than a count of every event episode. This distinction matters when participants may report multiple events. A participant-level endpoint answers how many participants experienced an event under the registry definition; it does not describe the total burden of event episodes. The record does not report the event-level data or the rules used to handle repeat events, so those details cannot be reconstructed.

The adverse-event results list participants at risk and participants affected for serious and other events. A count is easy to interpret as an observed frequency within the study, but it does not account for differences in follow-up time, participant characteristics, or completeness of reporting unless the analysis explicitly addresses them. The stated endpoint timeframe is approximately 3 months. More detailed follow-up information and a method for handling differing exposure time are not reported in the registry record.

Why is uncertainty relevant?

In general, an observed count is an estimate based on the participants who were followed and assessed. A confidence interval expresses the range of values that remain reasonably compatible with the observed data under a specified statistical model. It conveys precision, not the probability that a treatment is effective or safe. Confidence intervals and other uncertainty estimates for the posted adverse-event counts are not reported in the registry record. Without them, the counts should be read as descriptive observations rather than precise estimates of event frequency in a broader population.

For a binary outcome, methods may model the probability that a participant experiences an event. In larger samples, simple approximations can be useful, but sparse counts can make those approximations unreliable. Exact or small-sample methods may be considered in general when events are uncommon or group sizes are limited. The registry record does not report which method, if any, was used for formal inference on the primary endpoint. No p-value or confidence interval should be inferred from the counts alone.

What would a comparison require?

A treatment comparison needs a meaningful comparator and an analysis that accounts for how participants entered each group. Here, allocation was non-randomized, and no control group is identified. The listed cohorts are described by lesion involvement, not as randomized treatment assignments. A difference in observed counts between cohorts would therefore not isolate a treatment effect. Adjustment for baseline characteristics could sometimes address measured differences, but the registry record does not report such an analysis or the relevant participant-level covariates.

General planning calculations can translate an assumed effect and design into a prospective sample-size illustration. The stated planning assumptions refer to a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a fraction of the observed effect. Such illustrations are planning aids, not evidence about the study's achieved power and not observed outcomes. They do not establish the trial's original design rationale. The sample-size justification, prespecified effect, and original statistical plan are not reported in the registry record.

How should the safety categories be read?

The registry separates serious events from other adverse events. These are categories used to describe reported safety information; they should not be merged or interpreted as interchangeable measures. Seriousness does not necessarily mean that an event was caused by treatment, and an event classified as other can still matter clinically. In general, a complete safety assessment considers event type, timing, severity, duration, outcome, and relationship to treatment, as well as participant-level counts. Much of that detail is not reported in the registry record.

Multiplicity is also relevant when a study tracks several outcomes. Repeated testing across outcomes can increase the chance of finding a nominally notable result by chance. The record lists 7 outcome measures, but does not report a testing hierarchy, adjustment for multiple comparisons, or a statistical analysis plan. It is therefore not possible to assess how any formal efficacy tests were prioritized or interpreted. Numerical results for the listed secondary clinical outcomes are not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Cohort A", "Cohort B", "Cohort C", "Cohort D", "Cohort E")
n      <- c(5, 5, 5, 5, 5)
events <- c(2, 4, 2, 1, 2)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Cohort A  5  2  40.0  5.3  85.3  11.8  76.9  11.8  77.7
ARM  Cohort B  5  4  80.0  28.4  99.5  37.6  96.4  35.9  95.7
ARM  Cohort C  5  2  40.0  5.3  85.3  11.8  76.9  11.8  77.7
ARM  Cohort D  5  1  20.0  0.5  71.6  3.6  62.4  4.3  64.1
ARM  Cohort E  5  2  40.0  5.3  85.3  11.8  76.9  11.8  77.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 7 outcome measures, including secondary measures of target-lesion severity, psoriatic lesion area, and Physician Global Assessment. The information available does not report a prespecified hierarchy of outcomes, multiplicity adjustment, or a statistical analysis plan. When several outcomes are tested, general statistical practice recognizes that the chance of at least one apparently notable result can increase unless the testing strategy accounts for multiple comparisons. Without the planned strategy and the numerical outcome results, it is not possible to evaluate multiplicity or determine which outcome should carry the greatest inferential weight.

Missing-data methods and analysis populations are not reported in the registry record. The record does not specify how participants with incomplete follow-up, missing assessments, treatment discontinuation, or unavailable event information were handled. It also does not define whether the primary analysis included all enrolled participants, treated participants, or another population. These details matter because exclusions and incomplete observation can change the interpretation of participant counts and clinical outcome estimates.

The registry lists 0 analyses, but that entry does not explain the status of analysis documentation. The statistical plan, any prespecified interim analyses, and the rationale for the planned enrollment are not reported in the registry record. These omissions limit assessment of whether the posted endpoints and analyses followed prespecified methods. No assumptions about those procedures can be made from the design description alone.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: schizophrenia, paranoid type (20.0%).

The registry reports serious adverse events for Cohorts A through E. Cohort A had 0 of 5 participants at risk affected, Cohort B had 0 of 5, Cohort C had 1 of 5, Cohort D had 0 of 5, and Cohort E had 0 of 5. The total is 1 of 25 participants at risk. The registry also reports 0 deaths.

For other adverse events, the recorded counts were 2 of 5 in Cohort A, 4 of 5 in Cohort B, 2 of 5 in Cohort C, 1 of 5 in Cohort D, and 2 of 5 in Cohort E; the total was 11 of 25. These figures are counts of participants, not counts of event episodes. The registry identifies Schizophrenia, paranoid type as a serious-event term at 20.0%; the basis for that percentage is not reported in the registry record.

These are descriptive safety observations from a non-randomized study. They do not show whether an event was caused by treatment, and they do not support a controlled comparison between cohorts. The record does not report the event-level details needed to assess timing, duration, outcome, or relationship to study drug.

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

The results establish that the registry records serious and other adverse events during this study, including a serious event in Cohort C, other adverse events across the listed cohorts, and no deaths. They are useful as a record of what was observed in the enrolled participants and as context for understanding the study's safety reporting. The counts should be interpreted alongside the study's non-randomized, open-label design and its limited cohort sizes.

They do not establish that topical ruxolitinib caused any reported event. Without a randomized comparator, the observed events cannot be separated from events that might have occurred in the absence of treatment or under another treatment. Nor do the cohort counts establish that one cohort had greater or lesser risk than another: cohort descriptions differ by lesion involvement, and the registry does not report random assignment or a comparative statistical analysis.

The results also do not establish an absence of risk. The reported absence of deaths is limited to the posted record and observation period; it cannot show that serious outcomes are impossible. Counts alone do not describe the complete clinical course of an event, the degree of harm, or how long participants were observed. Those details are not reported in the registry record.

The title and outcome list identify preliminary efficacy and clinical measures, but their numerical results are not reported in the registry record. Consequently, the available data do not support a conclusion about changes in lesion severity, lesion area, or Physician Global Assessment. The study's existence and design can be described, but no benefit-harm judgment or treatment recommendation follows from these counts.

In general, conclusions about treatment effects require a suitable comparison, prespecified analysis, adequate outcome information, and estimates of uncertainty. The registry information available does not report those elements in sufficient detail for a comparative efficacy assessment. The defensible interpretation is therefore descriptive: these are the adverse-event counts recorded for this study, not a causal estimate or a definitive characterization of safety or efficacy.

14. Why This Trial Matters Statistically

This trial illustrates why design and outcome definitions matter when reading clinical results. Its primary endpoint is a participant count for treatment-emergent adverse events, with a stated timeframe of approximately 3 months. That definition directs attention to events occurring after treatment begins, but it does not by itself determine whether treatment caused them. The distinction between temporal association and causation is especially important in an open-label, non-randomized study.

The cohort structure also makes the scope of comparison clear. The cohorts are described by the extent of lesion involvement, and the record does not identify a randomized control group. Comparing their observed counts as though they were interchangeable treatment arms would ignore the design. Statistical methods cannot repair the absence of a suitable comparator or guarantee that non-randomized groups are comparable.

The safety counts demonstrate how a registry can communicate observed events while leaving important uncertainties unresolved. Participant counts convey whether events were recorded, but not their full clinical course, treatment attribution, or precision. The serious-event term and percentage also need context because the basis of the percentage is not reported in the registry record. Reading these details cautiously is part of sound statistical interpretation.

The study also lists clinical efficacy outcomes without numerical results in the information available. That distinction prevents the aims of a trial from being mistaken for evidence that those outcomes changed. More broadly, a registered outcome, an observed result, and a comparative treatment effect are different things. Keeping them separate helps readers avoid overstating what a small, non-randomized study can establish.

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 principal limitation for interpretation is the non-randomized, open-label design. No control group is identified, and the cohorts are described by lesion involvement rather than randomized assignment. Differences between cohorts cannot be attributed to treatment without additional design and analysis information. Knowledge of treatment may also influence reporting or assessment, although the registry does not report whether or how such effects were evaluated.

The cohort-level safety counts are limited in size: each listed cohort has 5 participants at risk. Such counts offer only a narrow description of observed events and do not establish precise event frequencies. Uncertainty estimates are not reported in the registry record. The primary endpoint timeframe is approximately 3 months, and more detailed follow-up or exposure information is not reported.

The available information does not include detailed event-level data, event timing, duration, outcomes, or treatment attribution. It also does not describe how repeat events or incomplete safety observations were handled. The record's serious-event term is listed at 20.0%, but the basis for that percentage is not reported in the registry record.

Information needed to assess efficacy is also absent: numerical results for the listed secondary outcomes are not reported in the registry record. The statistical analysis plan, missing-data methods, analysis populations, multiplicity strategy, sample-size justification, and any interim analyses are not reported. The registry lists 0 analyses, but does not explain that entry. These gaps prevent a full assessment of the prespecified analysis and limit conclusions to the descriptive details recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Open Label, Safety and Efficacy Study of Topical Investigational Drug to Treat Patients With Psoriasis — NCT00617994.
• Registry record last updated 2022-02-08; status last verified 2022-02.
• Results first posted 2022-02-08.
• 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

NCT00617994 is a completed Phase 2 study of topical ruxolitinib in patients with plaque psoriasis. It was open-label, non-randomized, and parallel, with enrollment of 25. The registry lists a start date of 2007-08-31 and primary completion date of 2009-04-30.

The primary endpoint measures participants with treatment-emergent adverse events over approximately 3 months. The posted safety counts report 1 serious adverse event among 25 at risk, 11 participants with other adverse events among 25 at risk, and 0 deaths. The study also lists lesion-severity, lesion-area, and Physician Global Assessment outcomes, but their numerical results are not reported in the registry record.

Because there is no randomized control group, the safety counts are descriptive and do not establish causation or comparative treatment effects. Detailed statistical methods, missing-data handling, and the rationale for planned enrollment are not reported in the registry record.