Study to Evaluate PF-04965842 in Patients With Moderate to Severe Psoriasis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Evaluate PF-04965842 in Patients With Moderate to Severe Psoriasis (NCT02201524), a randomized phase 2 study. The primary outcome is Change From Baseline in Psoriasis Area and Severity Index (PASI) Score at Week 4.

2. Clinical Question

The trial was randomized, parallel-group, placebo-controlled, and described as triple-masked. These design features set out a comparison of several dosing regimens against placebo, but the registry record does not say which groups were masked or provide enough outcome data to interpret the primary comparison. The clinical question should therefore be read as the question the study was designed to address, not as evidence of a particular treatment effect.

3. Trial Design

This was a Phase 2 randomized, double-blind, placebo-controlled study, with the registry describing the masking as triple. It used a parallel-group model. The trial was listed as terminated. The registry record gives an enrollment figure of 59, a start date of 2014-11, and a primary completion date of 2015-09. It does not report why the study was terminated, so the status alone does not establish whether termination was related to safety, efficacy, recruitment, or another reason.

Four groups are described: PF-04965842 200 mg once daily, PF-04965842 400 mg once daily, PF-04965842 200 mg twice daily, and placebo daily. The planned treatment period was 4 weeks, with a 4 week follow-up period. Registered secondary outcomes include PASI changes and percentage reductions at several follow-up weeks, the proportion achieving a Physician Global Assessment of clear or almost clear, and changes in fasting lipids and lipid ratios. The registry lists 19 outcome measures and 116 analyses.

Randomization is intended to distribute participant characteristics across treatment groups, while masking can reduce the influence of treatment knowledge on care, assessment, or reporting. Those are general design principles; the record does not describe the randomization sequence, allocation concealment, masking procedures, or the identity of the people covered by triple masking. It also does not report the actual number randomized to each arm or the number who completed treatment and follow-up.

The primary outcome is defined as change from baseline in PASI score at Week 4. Although the outcome definition and analysis population are specified, numerical estimates and uncertainty measures for that endpoint are not reported in the registry record. As a result, the design can be described, but the intended primary efficacy comparison cannot be assessed from the posted results described in the 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: The modified intent to treat (mITT) analysis set included all randomized participants who received at least 1 dose of the randomized study drug (PF-04965842 or placebo). Here, 'n' signifies those participants who were evaluable at specified time point for each arm, respectively.

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: The full analysis set (FAS) included all randomized participants who received at least 1 dose of the randomized study drug (PF-04965842 or placebo).

6. Primary Endpoint

The registry lists the primary outcome as Change From Baseline in Psoriasis Area and Severity Index (PASI) Score at Week 4, measured over Baseline, Week 4.

The primary endpoint is change from baseline in the Psoriasis Area and Severity Index score at Week 4. PASI combines the body area affected by psoriasis with clinical assessments of erythema, induration, and scaling across the head and neck, arms, trunk, and legs. The resulting score ranges from 0, no disease, to 72, maximal disease, with higher scores representing greater severity. A change score expresses how the measured score at follow-up differs from the participant’s baseline measurement.

PASI is used as a structured measure of both the extent and severity of psoriasis. Considering affected area as well as lesion signs can capture changes that a measure of only one feature might not reflect. The registry lists the primary outcome as a mean, with standard deviation as its dispersion measure. These are descriptive summaries: the mean describes the group’s average change, while the standard deviation describes variation among individual changes. Neither summary, by itself, establishes how precisely a treatment-group difference is estimated.

The primary time point is Week 4, corresponding to the stated end of the 4 week treatment period. The registry also lists PASI outcomes at other weeks as secondary outcomes. The numerical Week 4 results, including group means, standard deviations, participant counts evaluable at that time point, and a between-group estimate with its uncertainty, are not reported in the registry record. Consequently, the endpoint definition explains what was intended to be measured but does not establish the magnitude or precision of any observed change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a continuous outcome: change in PASI score from baseline to Week 4. The registry identifies the summary measure as a mean and the dispersion measure as a standard deviation. These statistics answer different descriptive questions. A group mean describes the average change among the participants included in that group’s analysis. A standard deviation describes the spread of individual values around that mean. Neither should be confused with a confidence interval, which expresses uncertainty about an estimated quantity under a statistical model.

What would a treatment contrast represent?

In a randomized trial, a between-group contrast can compare the average change in one PF-04965842 group with the average change in placebo. This is distinct from asking whether a group changed from its own baseline: change over time within a group does not by itself identify what would have happened without the intervention. A contrast against a concurrent comparator is generally the relevant quantity for a randomized treatment comparison. The registry record does not report the primary-endpoint contrast, its confidence interval, or its test result, so none can be interpreted for this study.

How should a confidence interval be read?

In general, a confidence interval gives a range of values compatible with the observed data and the assumptions of the analysis. A narrower interval indicates greater precision than a wider interval, while an interval that includes values on both sides of a null contrast may leave the direction of the difference uncertain. These are general statistical principles, not findings from this trial. Since the primary result and its interval are not reported in the registry record, the precision of the planned comparison is unknown.

What does the analysis population mean?

The registry defines the modified intent-to-treat population as all randomized participants who received at least 1 dose of randomized study drug. This definition excludes randomized participants who did not receive a dose, while retaining those who did receive a dose according to the stated criterion. The registry also explains that the reported number at each time point refers to participants evaluable at that time point for each arm. Those time-specific counts matter because a mean based on fewer observed participants can have different precision from a mean based on more participants. The counts and the handling of missing Week 4 measurements are not reported in the registry record.

Why do repeated outcomes raise multiplicity questions?

The registry lists multiple outcome measures and analyses. PASI-related outcomes are recorded at multiple follow-up weeks, alongside other PASI thresholds, a Physician Global Assessment response, and lipid measures. In general, testing many outcomes or time points can increase the chance of at least one apparently notable result arising by chance if no adjustment or prespecified testing strategy is used. Multiplicity procedures can control or organize that risk, but the appropriate approach depends on the study’s aims and analysis plan. The registry record does not report whether any multiplicity adjustment, hierarchy, or other strategy was used.

Why can over-dispersion matter?

For outcomes that count events or classify participants as responders, a statistical model may make assumptions about variability. Over-dispersion means the observed variability is greater than a model expects; if ignored, standard errors may be too small and intervals or tests may appear more certain than warranted. This is a general concept. It does not establish that over-dispersion occurred in this trial, and the registry record does not describe the models used for the listed secondary outcomes.

What can planning illustrations tell readers?

Sample-size planning illustrations based on an observed effect are hypothetical design calculations, not observed power and not trial findings. The stated assumptions for such illustrations are 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. For continuous outcomes, the stated unit is participants per arm for 80% power or participants per arm for 90% power. Such calculations depend on assumptions and should not be read as the number enrolled, the number analyzed, or evidence that the study had a particular probability of detecting an effect. The registry record does not report the trial’s own sample-size justification or whether its original planning used these assumptions.

Overall, the methods concepts clarify what a complete report would allow readers to judge: the estimated group changes, the between-group contrast, its precision, the analysis population, and the treatment of missing data and multiple outcomes. Those numerical and analytic details are not reported in the registry record, so the statistical performance of the primary comparison cannot be evaluated from the information recorded.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 19 outcome measures and 116 analyses. The registered outcomes cover multiple time points and several kinds of measures, including PASI change, PASI response thresholds, Physician Global Assessment response, and lipid outcomes. When many outcomes or time points are examined, multiplicity becomes relevant: in general, repeated testing can raise the chance of obtaining at least one apparently positive result by chance. A prespecified hierarchy or statistical adjustment can address some multiplicity concerns. Whether this study used such an approach is not reported in the registry record.

The record defines the primary analysis population as randomized participants who received at least 1 dose of study drug. It also says the evaluable number is specific to each arm and time point. This definition does not explain how missing Week 4 PASI measurements were handled, whether participants with missing values were excluded from a particular analysis, or whether any imputation or sensitivity analysis was used. Those details are not reported in the registry record.

The registry’s enrollment entry is 59, but that figure does not identify the number analyzed for each endpoint. Arm-specific counts at the primary time point are not reported in the registry record. The record also does not report an intention-to-treat analysis including all randomized participants, or explain how any difference between randomized, treated, and evaluable populations was addressed.

The statistical analysis plan, sample-size justification, and any interim analyses are not reported in the registry record. Therefore, it is not possible to assess whether analyses followed a prespecified plan, how the study addressed multiple comparisons, or how missing data may have affected the primary estimate.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: transient ischaemic attack (7.1%).

The registry reports serious adverse event counts alongside the number at risk for each group. For placebo, 1 of 14 participants at risk had a serious adverse event. For PF-04965842 200 mg once daily, 0 of 15 did; for PF-04965842 400 mg once daily, 0 of 16 did; and for PF-04965842 200 mg twice daily, 0 of 14 did. These are the recorded counts for the groups and should be read as descriptive observations, not as proof that the groups differ in risk.

For other adverse events, the record reports 6 of 14 participants at risk in the placebo group, 7 of 15 in the 200 mg once-daily group, 14 of 16 in the 400 mg once-daily group, and 11 of 14 in the 200 mg twice-daily group. The registry lists transient ischaemic attack at 7.1% among the top serious adverse event terms. The record does not give enough detail to establish a causal relationship or to interpret that term as a comparative treatment effect. Death counts are not reported in the registry record.

These figures reflect the recorded groups and the study’s follow-up, not a complete measure of long-term safety. The record does not provide event-level timing, duration, severity details for all events, or the reasons for termination. Small group counts can also make descriptive differences unstable. No treatment recommendation or causal safety conclusion follows from these counts alone.

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

The record establishes that a randomized, placebo-controlled Phase 2 study was designed to compare three PF-04965842 dosing regimens with placebo in people with moderate to severe psoriasis. It identifies change in PASI score at Week 4 as the primary endpoint and defines the modified intent-to-treat analysis population. Those details clarify the intended question and the outcome measure.

They do not establish what the study found. Numerical primary-endpoint estimates, between-group contrasts, confidence intervals, and test results are not reported in the registry record. Therefore, the posted information does not show the magnitude, direction, or precision of any primary comparison. A missing result is not evidence that there was no effect, and it is not evidence that a treatment effect was present.

The registry also lists secondary outcomes, but listing an outcome is not the same as reporting an analysis. Without numerical results and information about analysis populations, missing observations, and multiplicity, readers cannot assess whether secondary findings are consistent with the primary question or how robust they might be. The safety counts are descriptive and likewise do not support a causal comparison on their own.

The status is terminated, but the reason for termination is not reported in the registry record. It would be inappropriate to infer that the study ended because of a particular efficacy, safety, recruitment, or operational issue. Nor does the registry provide the information needed to judge whether the planned sample size was adequate or whether the analyses were completed as planned.

The most defensible interpretation is limited: the registry records the design, outcome definitions, enrollment entry, and selected adverse event counts, while leaving the primary efficacy result and important analytic details unavailable. The record can describe what was intended to be tested, but it does not support a conclusion that PF-04965842 was effective, ineffective, equivalent to placebo, or associated with a particular comparative safety profile.

13. Why This Trial Matters Statistically

This trial illustrates why a clearly specified endpoint and a reported estimate are both needed for statistical interpretation. PASI is described as a combined measure of affected area and lesion severity, with a defined scale and a primary assessment at Week 4. That specification makes the intended outcome understandable. But without group summaries and a treatment contrast, readers cannot quantify the observed change or its uncertainty.

The study also has multiple regimens and a placebo group. A design with several active comparisons can raise questions about which contrast is primary, how other comparisons are organized, and how multiplicity is handled. The registry lists many outcomes and analyses, but does not report a statistical analysis plan or multiplicity strategy. This makes it difficult to distinguish confirmatory testing from broader outcome exploration.

Another statistical issue is the difference between enrollment and endpoint analysis. The record lists enrollment of 59, but defines a modified intent-to-treat population and time-specific evaluable counts. Without those counts and missing-data methods, readers cannot see how much information contributed to the primary result or assess whether exclusions might affect interpretation.

Finally, the termination status and reported safety counts show why context matters. The registry provides some safety observations, but does not explain the study’s termination or supply enough detail to support causal comparisons. Statistical interpretation depends not only on the choice of design and measure, but also on transparent reporting of estimates, uncertainty, analysis decisions, and participant flow. The gaps in this record limit what can be learned from the planned randomized comparison.

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 interpreting this trial is that numerical results for the primary endpoint are not reported in the registry record. Without group-level Week 4 changes, an estimated between-group contrast, and a measure of uncertainty, the primary clinical question cannot be answered from the record. The registry’s enrollment entry does not replace the endpoint-specific numbers needed to assess precision.

The registry does not report the number randomized to each group, the number evaluable for the primary outcome, or the number who completed treatment and follow-up. Although the mITT definition is given, missing-data handling and any sensitivity analyses are not reported in the registry record. This limits assessment of the analysis population and possible effects of unavailable measurements.

Many outcomes and analyses are listed, but the statistical analysis plan and multiplicity approach are not reported. The record also does not report the sample-size justification, interim analyses, or the reason the study was terminated. These omissions prevent evaluation of prespecification and of whether the final analyses reflect the intended plan.

Masking is described as triple, but who was masked and how masking was maintained are not reported in the registry record. Randomization procedures and allocation concealment are also not described. Safety reporting is limited to the listed event counts and a serious adverse event term; details needed to interpret timing, severity, and causal attribution are not available. The registry record therefore offers a limited account of both efficacy and safety, and its design information should not be mistaken for a complete trial report.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study to Evaluate PF-04965842 in Patients With Moderate to Severe Psoriasis — NCT02201524.
• Registry record last updated 2016-10-05; status last verified 2016-08.
• Results first posted 2016-10-05.
• 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

NCT02201524 is a randomized, parallel-group, placebo-controlled Phase 2 study of PF-04965842 in moderate to severe psoriasis. The registry describes triple masking and lists an enrollment of 59. Three PF-04965842 regimens—200 mg once daily, 400 mg once daily, and 200 mg twice daily—were compared with daily placebo. The stated treatment period was 4 weeks, followed by a 4 week follow-up period.

The primary outcome was change from baseline in PASI score at Week 4, analyzed in a modified intent-to-treat population defined as randomized participants who received at least 1 dose. The study is listed as terminated, with a start date of 2014-11 and primary completion date of 2015-09. Numerical primary-endpoint results and the reason for termination are not reported in the registry record. Selected adverse event counts are recorded, but they do not establish a causal or comparative safety conclusion.