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 PsA Treatment With hOKT3γ1 (Ala-Ala) (NCT00239720), a randomized phase 2 study. The primary outcome is Proportion of Participants Who Received at Least Two Cycles of Treatment and Who Showed Predefined Levels of Improvement in Primary Efficacy Parameter at Six Months.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00239720 |
| Phase | Phase 2 |
| Condition | Arthritis, Psoriatic |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Enrollment | 4 |
| Arms in the primary outcome | n/a |
| Lead sponsor | National Institute of Allergy and Infectious Diseases (NIAID) |
| Results posted | Yes |
2. Clinical Question
Population
The trial concerned people with psoriatic arthritis who were unable to control their arthritis with methotrexate or azathioprine. The primary outcome population is described as intent-to-treat. Further eligibility details and participant characteristics are not reported in the registry record.
Intervention
The experimental intervention was hOKT3γ1 (Ala-Ala), a man-made antibody. The regimen is described as an escalating intravenous dose given over 5 days of each 28 day cycle. The primary outcome required participants to have received at least 2 treatment cycles.
Comparator
The comparator was intravenous placebo, administered over 5 days of each 28 day cycle. The registry record describes randomized allocation and double masking, but further details about how allocation and masking were implemented are not reported in the registry record.
Primary question
The study asked whether participants who received at least 2 cycles met a predefined improvement criterion at 6 months. The criterion combined improvement in a physician or participant global assessment with improvement in tender or swollen joint scores. The registry record does not report the observed primary outcome result or an analysis comparing the treatment and placebo groups.
The study therefore addresses a specific treatment question in a small registered trial, with the outcome defined by a combination of global assessment and joint-score changes. The registry record lists enrollment of 4 and a terminated status. It does not report why the trial was terminated, or whether the planned enrollment was achieved. Those details matter when interpreting the scope of any conclusions: the record establishes what the study set out to examine, but it does not provide an efficacy result that can answer the treatment question.
3. Trial Design
This was a Phase 2, randomized, double-blind, parallel-group trial comparing hOKT3γ1 (Ala-Ala) with placebo in psoriatic arthritis. The registry lists enrollment of 4. The study start date is 2006-03-16, the primary completion is listed as 2006-12, and the overall status is terminated. The reason for termination and the actual timing of termination are not reported in the registry record.
In a randomized design, assignment to intervention groups is intended to make the groups comparable, on average, with respect to factors that could affect outcomes. Double masking is intended to limit the influence of knowledge about assignment on participant experience, clinical assessment, and care. These are general purposes of randomization and masking; the registry record does not provide implementation details, such as the allocation procedure or who was masked. A parallel-group design assigns participants to a group and follows those groups rather than describing a crossover between interventions.
The intervention description specifies escalating intravenous doses over 5 days of each 28 day cycle. The placebo description specifies an intravenous dose over the same stated schedule. The outcome definition includes receipt of at least 2 cycles as part of the criterion for being counted as meeting the primary endpoint. The registry record does not report further dosing details, treatment adherence, or the number of participants in each group who completed treatment.
Although randomization and masking can strengthen a trial's design, they do not by themselves establish that a treatment effect was estimated reliably. The size of the enrolled sample, the number of outcome observations, the quality of outcome ascertainment, and the analysis all affect how much can be learned. With enrollment of 4 and no efficacy analysis reported in the registry record, the design description cannot substitute for an outcome comparison. Sample-size justification, planned enrollment details beyond the listed enrollment, and any protocol amendments 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.
Before assignment: At screening visit, participants underwent procedures to establish inclusion/exclusion criteria and then sign the informed consent form
Overall Study
| Stage | hOKT3gamma1 (Ala-Ala) | Placebo |
|---|---|---|
| STARTED | 3 | 1 |
| COMPLETED | 2 | 0 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | hOKT3gamma1 (Ala-Ala) | Placebo |
|---|---|---|
| Adverse Event | 1 | 0 |
| Lost to Follow-up | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-treat
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.
| Characteristic | Unit | hOKT3gamma1 (Ala-Ala) | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 3 | 1 | 4 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 3 | 1 | 4 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age, Continuous | years | 43.7 (SD 9.6) | 54 (SD 0) | 46.3 (SD 9.4) |
| Sex: Female, Male: Female | Participants | 2 | 0 | 2 |
| Sex: Female, Male: Male | Participants | 1 | 1 | 2 |
| Region of Enrollment: United States | participants | 3 | 1 | 4 |
6. Primary Endpoint
The registry lists the primary outcome as Proportion of Participants Who Received at Least Two Cycles of Treatment and Who Showed Predefined Levels of Improvement in Primary Efficacy Parameter at Six Months, measured over 6 Months.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint was the proportion of participants who received at least 2 treatment cycles and met the stated improvement criteria at 6 months. To meet the criterion, a participant had to improve by at least 1 unit from baseline in either physician global assessment or participant global assessment, and have at least 30% improvement from baseline in either tender or swollen joint scores. The endpoint is therefore a responder measure: it classifies whether each participant crosses the predefined thresholds, rather than describing every possible degree of change.
The joint scores assess 68 joints for tenderness and 66 joints for swelling. Each joint is rated from 0 to 3; total score ranges are 0-204 for tenderness and 0-198 for swelling. Higher scores indicate more severe symptoms. Considering change from baseline allows the endpoint to reflect improvement relative to each participant's starting score. The global assessments add an overall appraisal from the physician or participant, while the joint scores represent tenderness or swelling across specified joints.
A threshold-based endpoint can make a clinical outcome easier to interpret as a participant-level response, but it also depends on the chosen thresholds and the exact combination of criteria. Here, improvement in a global assessment is joined with improvement in a joint score, and treatment exposure is also part of the definition. The registry record does not report the number or proportion meeting this endpoint, the group-level analysis, or uncertainty around an estimated response. It therefore describes what was to be measured, but not the observed result.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the trial as randomized, double-blind, and parallel-group, and lists enrollment of 4. It also describes a clear six-month response definition. However, the registry record reports no analysis results for the primary outcome. There is consequently no posted estimate of the proportion meeting the criteria in either group, no between-group effect estimate, and no confidence interval or p-value for the primary question. The treatment comparison cannot be interpreted as showing either benefit or lack of benefit from the information in the registry record.
That absence is different from a finding of no difference. A null result would require an analysis of the observed outcomes and a reported estimate indicating little or no contrast, together with information about its precision. No such result is reported in the registry record. Nor is there a reported primary outcome result from which to assess whether the response criterion was met by any participants. The trial's terminated status does not explain the missing result: the reason for termination and the circumstances surrounding outcome collection are not reported in the registry record.
The enrollment of 4 is important context for the scale of the study, but it should not be turned into a numerical efficacy claim. The record does not report the allocation counts by arm for the primary outcome, the number with outcome assessments at 6 months, or the number satisfying the endpoint. In the absence of those data, neither a response proportion nor a treatment contrast can be reconstructed. No numerical calculations should be inferred from the safety counts, because they are not the primary efficacy endpoint.
In general, a confidence interval describes a range of values compatible with the observed data under the analysis assumptions; a narrow interval indicates greater precision than a wide interval. Here, no primary outcome confidence interval is reported in the registry record, so precision for the efficacy contrast cannot be assessed. Similarly, a p-value would address compatibility of data with a specified null model, but no primary analysis p-value is reported. These omissions prevent an assessment of statistical evidence and uncertainty, not merely a judgment about whether a threshold for statistical significance was crossed.
There are limited safety counts in the registry record, including counts of participants with serious and other adverse events. Those figures are descriptive and must be read with their small at-risk groups in mind. They do not fill the gap in efficacy reporting and cannot establish a comparative treatment effect. Overall, the registry record establishes that the study was planned as a randomized comparison and describes its primary measure, but leaves the primary efficacy result and its uncertainty not reported in the registry record.
9. Statistical Methods Explained
What does the design contribute?
Randomized allocation is a design method intended to reduce systematic differences between intervention groups. If implemented as planned, assignment by chance can help distribute both measured and unmeasured participant characteristics across groups. This is a general property of randomized trials, not evidence that balance was achieved in this particular study. The registry record does not report baseline characteristics, allocation details, or an assessment of group balance. With enrollment of 4, the record's design label should not be mistaken for proof that the groups were comparable in every respect.
Double masking is generally intended to reduce the possibility that knowledge of assignment influences behavior, clinical management, or outcome assessment. It is especially relevant when an endpoint includes physician or participant global assessment. The registry record labels the trial double-blind but does not report who was masked, how masking was maintained, or whether it was assessed. The parallel-group model means the registered comparison is between groups assigned to treatment and placebo; the record does not describe participants switching between them.
How is the primary endpoint constructed?
The endpoint is a binary responder classification built from several conditions. It requires receipt of at least 2 cycles, a specified improvement in either physician or participant global assessment, and at least 30% improvement in either tender or swollen joint scores at 6 months from treatment start. This combines exposure, overall assessment, and joint-specific measures. The criteria use “either” within the global assessment options and within the joint-score options, while requiring improvement from baseline in both of those broader domains.
In general, defining a responder threshold can make a result easier to express as the proportion meeting a clinically specified criterion. It can also discard information about the size of changes within each category: participants just meeting a threshold and those exceeding it may be counted in the same response category. Conversely, those near but not meeting a threshold may be classified as nonresponders. These are general properties of threshold-based outcomes. The registry record does not report the observed distribution of changes or the rationale for the chosen cutoffs.
The tender and swollen joint scores are formed by rating specified joints from 0 to 3 and combining the ratings into total scores. Tenderness is assessed across 68 joints, with a total score range of 0-204; swelling is assessed across 66 joints, with a total score range of 0-198. Higher scores indicate more severe symptoms. The endpoint uses percentage improvement from baseline in either joint score, but the registry record does not report baseline values, follow-up values, or how missing joint assessments were treated.
What can be learned from a group comparison?
For a binary response outcome, a group comparison would ordinarily use the response counts and the number assessed in each group to estimate how response differs between treatment and placebo. Statistical uncertainty would depend on the number of participants and the observed response pattern. No such primary outcome counts or comparison are reported in the registry record. As a result, the efficacy effect estimate, its precision, and any test of a treatment contrast are not available for interpretation.
In general, a confidence interval communicates uncertainty about an estimated quantity, conditional on the model and data used. It does not establish that every value in the interval is equally plausible, and it does not resolve limitations in design or data quality. A p-value measures how unusual the data would be under a specified null hypothesis and assumptions; it is not the probability that a treatment is effective or ineffective. These concepts are relevant to trial interpretation, but no primary endpoint confidence interval or p-value is reported in the registry record.
Over-dispersion is a general concern when observed variability exceeds what a statistical model expects. For count outcomes, for example, a model that assumes variability is tightly linked to the mean may understate uncertainty if the data are more variable than that assumption allows. The primary outcome is described as a proportion, not a count-rate endpoint, and the registry record does not report an analysis model or evidence of over-dispersion. It would be inappropriate to infer that this issue was tested or addressed.
What do planning illustrations mean?
Sample-size calculations are planning exercises: they ask what sample size might be needed under stated assumptions about the target effect, significance level, allocation, and statistical method. They are not evidence that an observed effect is real, and they are not “observed power.” The registry record describes planning assumptions of a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the target effect defined as a stated fraction of the observed effect. It also says that sample-size justification for the trial itself is not reported in the registry record.
Any planning illustration based on an observed effect should be interpreted cautiously, especially when the underlying trial result is unavailable in the registry record. Such an illustration is distinct from the study's original design justification and cannot establish that the trial had adequate power. The record does not provide a single reduced primary comparison: the primary measure has several categories or time points and is not reduced to one comparison. Numerical planning outputs and the assumptions needed to interpret a specific target comparison are not reported in the registry record.
What is missing from the analysis record?
The registry lists one outcome measure and zero analyses. It identifies the primary population as intent-to-treat, but does not describe how that population was operationalized, whether every randomized participant was included in the efficacy analysis, or how participants without a six-month assessment would be handled. The analysis method, covariate adjustment, missing-data approach, and prespecified hypothesis-testing procedure are not reported in the registry record. Those are not details that can be inferred from the randomized, double-blind design or the endpoint description.
In general, transparent reporting of the analysis population and missing-data handling is important because excluding participants or imputing unavailable outcomes can alter an estimate. Likewise, prespecified analysis methods can help distinguish planned analyses from choices made after examining the data. These are general methodological considerations. For this trial, the registry record does not provide enough information to evaluate these choices, and it reports no primary efficacy analysis to assess.
10. Multiplicity, Missing Data and Analysis Populations
The primary endpoint is described as one outcome measure, but its response definition includes alternative global assessments and alternative joint-score measures. These are components of a single predefined criterion in the record, not a basis for assuming that separate statistical tests were conducted. The registry record lists zero analyses and does not describe any multiplicity adjustment, testing hierarchy, or other approach to controlling the chance of false-positive findings across multiple analyses. Whether such procedures were specified in a protocol is not reported in the registry record.
In general, multiplicity arises when several hypotheses or outcomes are tested and the collection of tests is interpreted together. Without an adjustment or a clearly prespecified hierarchy, repeated testing can make apparently strong evidence more likely to arise by chance. This is a general statistical concern, not a claim that the trial performed multiple tests. With no analysis results reported, there is no set of efficacy tests to evaluate for multiplicity.
The primary population is labeled intent-to-treat. In general, an intent-to-treat analysis aims to retain participants in the groups to which they were randomized, regardless of treatment received, preserving the randomized comparison. The record does not explain how this principle was applied, which participants had usable six-month outcomes, or how missing values were handled. The endpoint also requires at least 2 cycles, but the registry record does not state how participants who did not meet that exposure criterion were treated in the analysis population.
Methods for handling missing outcomes, including whether an analysis used observed cases or an imputation procedure, are not reported in the registry record. Reasons for missing assessments and the extent of missingness are also not reported. These details are important because incomplete follow-up can affect both the estimated response and the uncertainty around it. The absent analysis details should not be filled in by assuming a conventional method.
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 |
|---|---|---|---|
| hOKT3gamma1 (Ala-Ala) | 1 | 3 | 33.3% |
| Placebo | 0 | 1 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| hOKT3gamma1 (Ala-Ala) | 2 of 3 |
| Placebo | 1 of 1 |
Most frequent serious adverse event terms
| Event term | Organ system | hOKT3gamma1 (Ala-Ala) | Placebo |
|---|---|---|---|
| Cytokine release syndrome | Immune system disorders | 1 of 3 | 0 of 1 |
Most frequent non-serious adverse event terms
| Event term | Organ system | hOKT3gamma1 (Ala-Ala) | Placebo |
|---|---|---|---|
| Headache | Nervous system disorders | 2 of 3 | 1 of 1 |
| Lymphopenia | Blood and lymphatic system disorders | 2 of 3 | 0 of 1 |
| Nausea | Gastrointestinal disorders | 2 of 3 | 0 of 1 |
| Chills | General disorders | 2 of 3 | 0 of 1 |
| CD4 lymphocytes decreased | Investigations | 1 of 3 | 1 of 1 |
| Myalgia | Musculoskeletal and connective tissue disorders | 2 of 3 | 0 of 1 |
| Hyperhidrosis | Skin and subcutaneous tissue disorders | 2 of 3 | 0 of 1 |
| Leukopenia | Blood and lymphatic system disorders | 1 of 3 | 0 of 1 |
| Dyspepsia | Gastrointestinal disorders | 1 of 3 | 0 of 1 |
| Pyrexia | General disorders | 1 of 3 | 0 of 1 |
Serious events with the highest arm-level rate: cytokine release syndrome (33.3%).
For hOKT3γ1 (Ala-Ala), the registry lists 3 participants at risk for serious adverse events and 1 participant affected. For placebo, it lists 1 participant at risk and 0 affected. For other adverse events, the corresponding counts are 3 at risk and 2 affected in the hOKT3γ1 (Ala-Ala) group, and 1 at risk and 1 affected in the placebo group. These are small group counts, and the registry record does not provide further detail about event timing, severity beyond the serious-event classification, or participant-level overlap between categories.
The registry record lists cytokine release syndrome as the top serious term and gives 33.3%. The record does not provide enough detail in this listing to interpret that percentage beyond its appearance as a reported serious-event term. The counts of participants affected should not be read as counts of total events unless the record explicitly says so; these figures describe affected participants.
These are descriptive safety data, not a reliable basis for estimating comparative risk. With such small at-risk groups, a count can change substantially in meaning if another participant is observed, and the figures cannot establish that an event is more or less likely under either assignment. The registry record also does not provide a reported death count, and that value should not be interpreted as a confirmed absence of deaths.
12. What the Result Does, and Does Not, Mean
The registry record establishes the intended clinical comparison: hOKT3γ1 (Ala-Ala) versus placebo for psoriatic arthritis, using a six-month response criterion. It describes randomization, double masking, the treatment schedules, the endpoint definition, enrollment of 4, and a terminated study status. These details help define what the trial set out to investigate and the scale at which it was registered.
It does not establish whether the intervention met the primary endpoint, whether the groups differed, or how precisely any difference was estimated. No primary outcome result, group-level efficacy estimate, confidence interval, or p-value is reported in the registry record. Therefore, the absence of a reported positive result cannot be interpreted as evidence that treatment had no effect, and the study design description cannot be taken as evidence that it did have an effect.
The trial's small enrollment is a central limit on what can be inferred from the record. The registry does not report the allocation counts for the primary analysis, the completeness of six-month follow-up, or the response counts. Without these, the endpoint cannot be reconstructed and statistical uncertainty cannot be evaluated. The terminated status adds context but does not explain why the study ended; the reason and consequences for outcome collection are not reported in the registry record.
The safety counts are also limited descriptive observations from small at-risk groups. They should not be converted into broad statements about comparative safety, and the listed serious-event term does not resolve the missing efficacy information. For the same reason, planning assumptions cannot compensate for absent observed results. A planning illustration is not an observed estimate and cannot show what happened to participants in this trial.
The careful conclusion is narrow: the registry describes a randomized Phase 2 trial and specifies its primary outcome, but it does not report the primary analysis needed to answer the efficacy question. Any conclusion about the size, direction, or precision of an efficacy effect is not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates why registration details and results need to be distinguished. A registry entry can describe a randomized design, masking, treatment schedules, and a prespecified outcome without providing the analysis that would show how participants fared. Readers can identify the intended question and the endpoint's structure, but they cannot infer an efficacy result from those design features alone.
The endpoint also illustrates how a composite responder definition is built. It combines a global assessment, joint-score improvement, a time point, and a treatment-exposure condition. Such definitions can be useful because they translate several kinds of clinical information into a participant-level classification. At the same time, interpretation depends on understanding each component, its threshold, and the handling of participants who do not have complete measurements. The registry record describes the criteria but does not report outcome data or the missing-data procedure.
The listed enrollment of 4 underscores the importance of precision and transparent reporting. Even when a trial is randomized and masked, conclusions depend on the amount and quality of observed data. Without response counts and an uncertainty estimate, the strength of evidence cannot be assessed. No efficacy analysis is reported in the registry record, so there is no result to distinguish a small estimated effect from a large but imprecise one.
Finally, the terminated status shows why status labels should not be treated as outcome findings. The record does not report the reason for termination or whether termination affected outcome collection. Statistical interpretation requires those details alongside complete results and analysis methods. The entry is informative about the study's intended design, but incomplete as a basis for assessing its primary treatment 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 trial-specific limitation for interpretation is the lack of a reported primary efficacy analysis. Although the registry defines a six-month endpoint, it does not report response counts, group-specific proportions, a treatment contrast, or uncertainty around that contrast. Enrollment is listed as 4, but group allocation for the efficacy outcome and follow-up completeness are not reported in the registry record. Consequently, the primary endpoint cannot be evaluated from the registered results.
The trial is listed as terminated. The reason for termination, the timing and circumstances of termination, and its effect on participant follow-up are not reported in the registry record. It is therefore not possible to determine whether the endpoint was collected as planned or whether the registered enrollment represents the intended target. Sample-size justification and the original statistical plan are not reported in the registry record.
The endpoint depends on several criteria, including treatment exposure, a global assessment change, and a joint-score change. The registry provides the thresholds and score ranges but does not report baseline distributions, follow-up values, assessor-level details, or missing-data handling. It also does not report the analysis method or how the intent-to-treat population was implemented. These omissions limit assessment of both the endpoint measurement and the statistical analysis.
Safety information is limited to small at-risk groups and reported affected-participant counts. The record does not provide enough context for a broad comparative safety assessment, and the listed serious-event term should be interpreted descriptively. More generally, the design labels do not reveal whether masking remained intact or whether allocation achieved balance in this sample; those details are not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: PsA Treatment With hOKT3γ1 (Ala-Ala) — NCT00239720.
- Registry record last updated 2017-04-27; status last verified 2017-03.
- Results first posted 2012-03-21.
- 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
NCT00239720 is a Phase 2 randomized, double-blind, parallel-group trial of hOKT3γ1 (Ala-Ala) and placebo for psoriatic arthritis. Enrollment is listed as 4. The study started on 2006-03-16, primary completion is listed as 2006-12, and the status is terminated.
The primary outcome was the proportion of participants who received at least 2 treatment cycles and met the specified global-assessment and joint-score improvement criteria at 6 months. The primary population is identified as intent-to-treat. The registry record lists one outcome measure and zero analyses, and reports no primary efficacy result, analysis method, or missing-data approach.
Safety listings include serious and other adverse-event counts for the treatment and placebo groups, plus cytokine release syndrome as the top serious term at 33.3%. The reason for termination and sample-size justification are not reported in the registry record.