This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Safety and Efficacy Study of A Novel Ointment to Treat Plaque Type Psoriasis (NCT00755196), a randomized phase 2 study. The primary outcome is Percentage of Participants With Lowering of Overall Target Plaque Severity Score (OTPSS) at Day 84.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00755196 |
| Phase | Phase 2 |
| Condition | Psoriasis |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Triple |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Participants with plaque type psoriasis were eligible for the study. The record reports an enrollment of 30 and defines the ITT population as all randomized participants who received study medication. Further eligibility criteria and the number included in each analysis are not reported in the registry record.
Intervention
The intervention was AN2728 Ointment, 5%, applied twice daily for 12 weeks. The registry describes the study as a safety and efficacy evaluation. It does not report numerical primary outcome results that would show the observed change in target plaque severity.
Comparator
The comparator was AN2728 ointment vehicle, also applied twice daily for 12 weeks. The official title describes a bilateral study, and the primary outcome description compares ointment-treated plaques with vehicle-treated plaques. The registry does not report the numerical results of that comparison.
Primary question
At Day 84, what percentage of participants had a reduction in Overall Target Plaque Severity Score (OTPSS), comparing plaques treated with AN2728 Ointment, 5%, with vehicle-treated plaques? The record defines the outcome but does not report the percentage, a treatment contrast, or an uncertainty estimate. The comparative effect therefore cannot be assessed from the registry record.
3. Trial Design
This was a randomized Phase 2 study with an enrollment of 30 participants and a stated focus on safety and efficacy in plaque type psoriasis. The official title describes a double-blind, randomized, 12-week bilateral study of AN2728 Ointment, 5%, versus ointment vehicle. The registry fields classify masking as triple and the model as parallel. These are the design labels recorded, while the title and primary outcome description also make clear that plaques treated with ointment and vehicle were compared.
The study objective was to evaluate AN2728 Ointment, 5%, against ointment vehicle when applied twice daily for 12 weeks. The primary outcome was assessed at Day 84. Secondary outcomes tracked the percentage of participants with lowering of OTPSS at Day 7, 14, 28, 42, 56, 70, and 91. The record does not provide numerical results for these outcomes.
The sponsor is Pfizer. The record lists the study start as 2008-09, primary completion as 2008-12, and status as completed. These registry entries describe the planned and recorded study framework; they do not establish the size or precision of any treatment effect. The number of participants assigned to each treatment, the randomization procedure, and the identities of the parties masked are not reported in the registry record.
The bilateral description matters when interpreting the comparison: the primary outcome text refers to ointment-treated plaque versus vehicle-treated plaque, rather than presenting a numerical participant-level result for separate treatment arms. The registry model label is parallel, but further details reconciling that classification with the bilateral comparison are not reported in 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
| Stage | AN2728 5 Percent (%) Ointment + Ointment Vehicle |
|---|---|
| STARTED | 30 |
| COMPLETED | 28 |
| NOT COMPLETED | 2 |
Reasons for not completing this period:
| Reason | AN2728 5 Percent (%) Ointment + Ointment Vehicle |
|---|---|
| Lost to Follow-up | 1 |
| Lack of Efficiency | 1 |
Analysis population for the primary outcome, as defined in the registry: ITT population included all randomized participants who received the study medication.
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: Intent-to-treat (ITT) population included all randomized participants who received the study medication.
| Characteristic | Unit | AN2728 5% Ointment + Ointment Vehicle |
|---|---|---|
| Participants analysed | 30 | |
| Age, Continuous | years | 48.4 (SD 8.63) |
| Gender: Female | Participants | 0 |
| Gender: Male | Participants | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Lowering of Overall Target Plaque Severity Score (OTPSS) at Day 84, measured over Day 84.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with lowering of Overall Target Plaque Severity Score (OTPSS) at Day 84. The registry describes OTPSS as an investigator assessment of plaque severity. Each target plaque receives a score from 0, meaning no plaque, to 8, meaning very severe plaque; a higher score indicates greater severity. The outcome counts participants whose score was reduced and reports that percentage, with the description specifying a comparison of ointment-treated plaque and vehicle-treated plaque.
A percentage with a reduction offers an interpretable summary of how often the measured plaque score decreased by the assessment time. It differs from a mean score change: it focuses on the proportion meeting the reduction criterion rather than the average size of score changes. As a general statistical point, a binary outcome of this kind can be useful for communicating the frequency of an observed event, but it does not by itself show how large the score reduction was or whether a change was important to participants.
The registry does not define a minimum reduction required to count as lowering, nor does it report the Day 84 percentage, comparative effect, confidence interval, or test result. Those details are not reported in the registry record, so the endpoint definition alone cannot establish the observed magnitude or precision of the comparison.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes the primary outcome and study design but does not report the numerical primary outcome result. It identifies the Day 84 measure as the percentage of participants with lowering of OTPSS and describes a comparison between ointment-treated and vehicle-treated plaques. It does not give either percentage, the difference between them, a confidence interval, or a p-value. Consequently, the posted information does not establish the direction, magnitude, or statistical precision of the primary comparison.
This is an important distinction between an outcome definition and an outcome finding. A definition explains what investigators intended to measure: a reduction in an investigator-rated plaque severity score by a specified assessment. A finding would require the observed data and an analysis of the comparison. Without those numerical results, readers cannot determine how frequently scores were reduced in either treatment condition or how much the conditions differed.
The planned context is a randomized Phase 2 study with 30 enrolled participants. The official title identifies a bilateral comparison, and the primary outcome description compares plaques treated with ointment and vehicle. The number of participants contributing evaluable Day 84 data, and how many plaques or observations contributed to each analysis, are not reported in the registry record. Enrollment alone does not establish the analysis sample size for this endpoint.
The secondary outcome description lists assessments at Day 7, 14, 28, 42, 56, 70, and 91. These repeated time points describe the intended follow-up schedule for lowering of OTPSS, but no numerical secondary outcome findings are reported in the registry record. It is therefore not possible to describe the trajectory of the measure or assess whether the primary assessment was consistent with other time points.
The registry includes safety counts for a combined group titled “AN2728 5% Ointment + Ointment Vehicle.” Those figures should be read as the recorded group-level safety information, not as separate estimates for each treatment condition. They do not supply missing efficacy results and cannot resolve the primary comparison.
In general, an estimated effect is more informative when presented with an uncertainty interval, because the interval conveys the range of values compatible with the data under the analysis. No such estimate or interval is reported for the primary endpoint. Thus, statistical significance, precision, and the clinical importance of any difference cannot be judged from the registry record. This is a limitation of the available report, not evidence that the treatments were equivalent or that no change occurred.
9. Statistical Methods Explained
The primary measure is a binary participant-level outcome: whether OTPSS was lowered by Day 84. The registry gives a percentage as the unit. In general, a percentage expresses the number of participants meeting a defined condition relative to the relevant analysis population. The exact rule for a qualifying reduction, the numerator and denominator, and the observed percentage are not reported in the registry record.
What does the score measure?
The OTPSS assessment is described as an investigator rating of target plaque severity. The score runs from 0, no plaque, to 8, very severe plaque, with higher values indicating more severity. The endpoint then converts the score information into an indicator of whether a participant had a reduction. As a general statistical concept, turning a graded score into a binary outcome can make the endpoint easier to express as a proportion, but it leaves out the size of the reduction and any differences among degrees of improvement. The registry does not report a continuous score analysis or an alternative definition of response.
How should the bilateral comparison be understood?
The official title calls the study bilateral, and the primary outcome description explicitly contrasts ointment-treated plaque with vehicle-treated plaque. This means the registry describes a comparison of treatment conditions at the plaque level within the study framework. In general, when two conditions are measured within the same participant, the observations may be related rather than independent. An analysis that accounts for this relationship can differ from one that treats all observations as unrelated. The statistical analysis used for this endpoint, including whether or how within-participant dependence was handled, is not reported in the registry record.
The registry also labels the model parallel. That classification is retained as a record detail, but the available description does not explain how the parallel-model label relates to the bilateral plaque comparison. Allocation details, the randomization unit, and any method for assigning treatment to plaques are not reported in the registry record. No further design mechanism should be inferred from the labels alone.
What would an effect estimate and interval add?
In general, an effect estimate expresses the observed difference or contrast between conditions, while a confidence interval describes uncertainty around that estimate under the chosen statistical method. A narrow interval indicates greater precision than a broad interval, though interpretation also depends on the endpoint and analysis. The registry record does not report a primary effect estimate or confidence interval. It also does not identify the statistical test, model, confidence level, or approach used to calculate uncertainty. No p-value is reported for the primary comparison.
For a binary endpoint, analysis could summarize response proportions and compare them using a suitable method. That is a general description, not a claim about the analysis conducted in this study. The method needs to match the design, outcome structure, and analysis population. The result cannot be reconstructed from the enrollment total because the endpoint counts and evaluable sample size are not reported.
What do the planning assumptions mean?
The registry record describes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. Such calculations, in general, are planning illustrations and are not observed power. The record's analysis information indicates that the illustration is skipped because there are fewer than two arms in the primary outcome. No planning sample-size values are therefore available to interpret for this comparison.
Even when a planning calculation is available, it depends on assumptions about the effect and analysis. It should not be confused with evidence about the effect actually observed or the precision achieved. In this record, the absent primary result prevents an independent interpretation of observed effect size, and the skipped planning illustration does not fill that gap.
What analysis details are missing?
The analysis method, effect measure, uncertainty calculation, hypothesis test, and treatment of missing endpoint data are not reported in the registry record. The record defines the ITT population as all randomized participants who received study medication, but it does not give the number from that population included in the primary analysis. It also does not describe handling of participants without a Day 84 assessment, adjustment for baseline score, or any covariates. These are material details because they help explain what the reported estimate would represent and how robustly it was obtained.
General statistical interpretation should therefore remain limited to the endpoint definition and design description. No recalculated comparison is possible from the posted summary information, and no result should be inferred from the study title, enrollment, or planning assumptions.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary endpoint at Day 84 and a secondary outcome measuring lowering of OTPSS at Day 7, 14, 28, 42, 56, 70, and 91. Multiple outcomes or assessment times can raise a multiplicity question: when many comparisons are tested, the chance of at least one apparently unusual result can increase. As a general statistical principle, a prespecified strategy may address that issue. Whether this study used an adjustment, testing sequence, or other multiplicity strategy is not reported in the registry record.
The record defines the ITT population as all randomized participants who received study medication. It does not state how many participants from that population contributed to the Day 84 endpoint, whether another analysis population was used, or how exclusions were handled. The number of participants with missing outcome data and the method for handling missing data are not reported in the registry record. No assumptions about missing outcomes or imputation should be inferred.
Interim analyses and a detailed statistical analysis plan are not reported in the registry record. The record also does not specify which outcomes or comparisons were prioritized in formal testing. Without these details and the numerical results, readers cannot determine how multiplicity, incomplete follow-up, or analysis-population decisions affected the efficacy findings.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| AN2728 5% Ointment + Ointment Vehicle | 1 | 29 | 3.4% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| AN2728 5% Ointment + Ointment Vehicle | 8 of 29 |
Most frequent serious adverse event terms
| Event term | Organ system | AN2728 5% Ointment + Ointment Vehicle |
|---|---|---|
| Drug eruption | Skin and subcutaneous tissue disorders | 1 of 29 |
Most frequent non-serious adverse event terms
| Event term | Organ system | AN2728 5% Ointment + Ointment Vehicle |
|---|---|---|
| Dermatitis contact | Skin and subcutaneous tissue disorders | 7 of 29 |
| Pharyngitis | Infections and infestations | 2 of 29 |
| Scab | Skin and subcutaneous tissue disorders | 1 of 29 |
| Drug eruption | Skin and subcutaneous tissue disorders | 1 of 29 |
Serious events with the highest arm-level rate: drug eruption (3.4%).
The registry reports one combined safety group titled “AN2728 5% Ointment + Ointment Vehicle.” For that group, 29 participants were listed as at risk for serious adverse events and 1 as affected. For other adverse events, 29 were listed as at risk and 8 as affected. These are the recorded group-level counts; the registry does not provide separate counts for the ointment and vehicle conditions in this entry.
The listed serious adverse event term is “Drug eruption,” with 3.4% recorded. The registry does not provide further detail in this summary about the event, its timing, outcome, or attribution to a treatment condition. A serious adverse event count and a listed term describe safety reporting; on their own, they do not establish causation or permit comparison between the treatment conditions.
The deaths field has no numerical value in the record, so the death count is not reported in the registry record. The safety figures should not be interpreted as a complete account of event severity, duration, or participant-level history, because those details are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry describes a randomized Phase 2 study intended to evaluate AN2728 Ointment, 5%, against ointment vehicle in plaque type psoriasis. It identifies a Day 84 endpoint based on the percentage of participants with lowering of OTPSS and a sequence of secondary assessment days. These details explain what investigators planned to assess, but they are not numerical evidence about the result.
The primary endpoint percentages, comparative effect, confidence interval, and p-value are not reported in the registry record. The available information therefore cannot show whether one condition had a higher percentage of participants with a reduced score, how large any difference was, or how precise an estimate might be. It also cannot establish whether a change was clinically important. Absence of a posted numerical result should not be interpreted as no effect, no change, or equivalence.
The enrollment of 30 describes the study size recorded by the registry, not the number necessarily included in the Day 84 analysis. The ITT definition is stated, but analysis counts and missing-data handling are not. Likewise, the listed safety figures are grouped together and do not provide a separate comparison between treatment conditions.
In general, clinical interpretation of a trial result depends on both the estimated effect and its uncertainty, along with the outcome definition and analysis population. Here, the endpoint definition and design description can be understood, but the absent numerical efficacy findings and limited analysis details prevent a statistical assessment of the comparative result. The registry information also does not support a conclusion about outcomes beyond the measures and follow-up described.
13. Why This Trial Matters Statistically
This study illustrates why a registry record must be read in layers. The design and endpoint description identify the question being studied, while numerical results are needed to assess the observed comparison. A randomized, triple-masked Phase 2 study with a bilateral description provides important context, but those features cannot substitute for an effect estimate or its uncertainty.
The outcome is based on lowering of an investigator-rated severity score, expressed as a percentage of participants. This makes the endpoint easy to describe as a response frequency, while also emphasizing the value of knowing the response definition and analysis method. The record gives the scale anchors and assessment timing, but does not report the minimum score change that qualifies as lowering or the statistical approach used.
The bilateral plaque comparison also highlights a design issue relevant to biostatistics: measurements within the same participant can be associated. In general, analysis should reflect the structure of the data. The registry does not report how that relationship was addressed, leaving readers unable to assess this part of the analysis.
Finally, a planning illustration and an observed treatment effect answer different questions. Planning calculations depend on assumptions; they are not observed power or a substitute for trial results. In this record the planning illustration is skipped, and the primary numerical result is not reported. The example underscores the need to distinguish a registered study question, a design description, a planned analysis, and reported evidence when interpreting clinical research.
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 consequential limitation for interpretation is that numerical primary outcome results are not reported in the registry record. The record does not give the Day 84 percentage for either treatment condition, a comparative effect, an uncertainty interval, or a p-value. Numerical results for the listed secondary assessment days are also not reported. This prevents assessment of effect direction, size, precision, or consistency over time.
Analysis details are limited. The record defines the ITT population but does not state the number analyzed at Day 84, the number with missing assessments, or the method for handling missing data. It does not report the statistical model or test, how the bilateral structure was handled, or whether baseline measurements or other variables were used. The number of participants in each treatment assignment is not reported in the registry record.
The endpoint is described as lowering of OTPSS, but the minimum reduction needed to count as lowering is not reported. The registry labels the model parallel while the official title and endpoint description identify a bilateral plaque comparison; further explanation of the design classification is not reported. The identities of masked parties and detailed randomization procedures are not reported either.
For safety, the posted group combines AN2728 Ointment and ointment vehicle, so it does not provide treatment-specific event counts. A death count is not reported in the registry record. These limitations constrain interpretation of both comparative efficacy and safety and should not be replaced by assumptions.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Efficacy Study of A Novel Ointment to Treat Plaque Type Psoriasis — NCT00755196.
- Registry record last updated 2017-03-06; status last verified 2017-01.
- Results first posted 2017-03-06.
- 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.
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18. Record Summary
The registry record describes NCT00755196, a completed randomized Phase 2 study sponsored by Pfizer. It enrolled 30 participants with plaque type psoriasis and evaluated AN2728 Ointment, 5%, against ointment vehicle, applied twice daily for 12 weeks. The official title describes a double-blind bilateral study; registry fields list triple masking and a parallel model. The record lists the start as 2008-09 and primary completion as 2008-12.
The primary outcome was the percentage of participants with lowering of OTPSS at Day 84. The score was an investigator assessment from 0, no plaque, to 8, very severe plaque. Secondary outcome assessments were listed for Day 7, 14, 28, 42, 56, 70, and 91. Numerical efficacy results and detailed analysis methods are not reported in the registry record. Safety counts are reported for a combined AN2728 5% Ointment plus ointment vehicle group, rather than separately for each treatment condition.