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 Study in Allergic Adults to Support the Development of Immunological Assays (NCT01320137), a non-randomized na study. The primary outcome is Number of Subject Responders With Antigen Specific Lymphocytes T Helper 2 (Th2) Cluster of Differentiation 4+ (CD4+) T Cells Expressing Cytokines.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01320137 |
| Phase | NA |
| Condition | Immunologic Tests |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 80 |
| Arms in the primary outcome | n/a |
| Lead sponsor | GlaxoSmithKline |
| Results posted | Yes |
2. Clinical Question
Population
Adults aged 18-45 years were assigned to an Allergy Group if they had symptomatic allergy to birch pollen, or to a Control Group if they had no known allergies. The primary endpoint population was narrower: the According-To-Protocol cohort of Bet v 1 BrdU+ subjects with observed peripheral blood mononuclear cell proliferation after 96 hours.
Intervention
The listed procedure was blood withdrawal. The study purpose was to develop and characterize immunological assays on blood samples, not to compare a therapeutic treatment.
Comparator
The registry describes a parallel comparison of the Allergy Group and Control Group. Allocation was non-randomized, so the groups were not formed by random assignment and should not be treated as a like-for-like controlled comparison.
Primary question
At Day 0, how many subjects met the responder definition for antigen-specific Th2 CD4+ T cells expressing IL-4, IL-5 and/or IL-13? A responder was identified by comparing concentration after Bet v 1 stimulation with a threshold based on the percentile 95 of concentrations after medium-only stimulation.
The question is assay-focused: it concerns whether cytokine-expressing cells can be identified under the stated laboratory definition in the eligible study population. The registry record does not report the primary responder counts or a statistical comparison between groups. It therefore does not establish how frequently responders were observed, how different the groups were on this endpoint, or how precisely any difference was estimated.
3. Trial Design
This completed study enrolled 80 participants and is listed as a parallel, non-randomized study with no masking. The registry lists the phase as NA. The study began on 2011-03-31 and had a primary completion date of 2011-05-11. GlaxoSmithKline is listed as the sponsor. The stated purpose was to develop and characterize immunological assays using blood samples.
Participants were described in two groups. The Allergy Group included adults aged 18-45 years with symptomatic allergy to birch pollen. The Control Group included adults aged 18-45 years with no known allergies. Because group assignment was not randomized, any observed group difference could reflect differences in who entered each group as well as differences related to allergy status. The registry itself cautions that the arms are not a like-for-like control comparison.
Blood withdrawal is the listed procedure. The record does not describe a treatment assignment or a masked assessment. This design is suited to describing assay measurements in the defined groups, but it does not by itself support a causal treatment comparison. The registry record does not report further details of participant recruitment, the planned allocation process, or the rationale for the enrollment target.
The main endpoint was measured at Day 0. Its analysis population was the According-To-Protocol cohort of Bet v 1 BrdU+ subjects for whom peripheral blood mononuclear cell proliferation with Bet v 1 was observed after 96 hours. The registry lists four outcome measures and zero analyses. The primary endpoint results and statistical comparisons 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 | Allergy Group | Control Group |
|---|---|---|
| STARTED | 40 | 40 |
| COMPLETED | 40 | 40 |
| NOT COMPLETED | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: The According-To-Protocol (ATP) cohort, Bet v 1 BrdU+ subjects included all subjects from the ATP cohort for which proliferation of peripheral blood mononuclear cells (PBMCs) with the birch pollen allergen Bet v 1 was observed after 96 hours.
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 | Allergy Group | Control Group | Total |
|---|---|---|---|---|
| Participants analysed | 40 | 40 | 80 | |
| Age, Continuous | Years | 30.1 (SD 7.44) | 28.6 (SD 6.92) | 29.35 (SD 7.18) |
| Sex: Female, Male: Female | Participants | 26 | 19 | 45 |
| Sex: Female, Male: Male | Participants | 14 | 21 | 35 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Subject Responders With Antigen Specific Lymphocytes T Helper 2 (Th2) Cluster of Differentiation 4+ (CD4+) T Cells Expressing Cytokines, measured over At Day 0.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Subjects |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of subjects classified as responders for antigen-specific Th2 CD4+ T cells expressing cytokines. The cytokines named are IL-4, IL-5 and/or IL-13, measured using flow cytometry and multiplex assays. The outcome is a count of subjects meeting a binary definition, rather than a continuous measurement of cytokine concentration or cell activity.
Responder status depends on a reference threshold. A subject qualifies when the concentration after Bet v 1 stimulation is above the percentile 95 of concentrations after medium-only stimulation, with that reference determined on Bet v 1 BrdU+ subjects. This definition uses the medium-only condition to represent the assay background against which stimulated concentrations are assessed.
Such a threshold can turn laboratory measurements into an interpretable count of subjects who cross a prespecified assay criterion. It does not, on its own, indicate the size of the underlying concentration change or the reliability of classification for an individual. The registry record does not report the responder counts, the threshold value, or uncertainty estimates for this primary endpoint. The endpoint is specified at Day 0 in the ATP cohort defined by observed PBMC proliferation after 96 hours.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives the study purpose, design, endpoint definition, and analysis population, but it does not report the primary outcome counts. As a result, the posted record does not permit a numerical description of the proportion or number of responders in either group, nor a comparison of those outcomes. No effect estimate, confidence interval, or p-value for the primary endpoint is reported in the registry record. The endpoint definition should not be mistaken for an outcome result.
The study is non-randomized and unmasked. The registry explicitly cautions that its arms are not a like-for-like control comparison. Any difference between the groups, if reported elsewhere, would therefore need to be interpreted as an observed group contrast rather than a causal effect of an intervention. The groups were defined by allergy status, and the listed procedure was blood withdrawal. The stated aim was assay development and characterization.
The endpoint is a count of subjects who pass a threshold based on concentrations after stimulation and medium-only conditions. Threshold-based responder status is useful as a classification, but it compresses the underlying assay measurements into a count. Without the distribution of concentrations, the number of eligible subjects, and the responder counts, it is not possible to assess the magnitude or stability of the group pattern. Those results are not reported in the registry record.
The registry lists four outcome measures and zero analyses. Two secondary outcomes concern subject responders with antigen-Th2 CD4+ T cells expressing IFN-γ, including an amended definition. The presence of these endpoint descriptions does not supply results or establish which comparisons were performed. The registry record does not report multiplicity adjustments or a complete analysis plan.
In general, uncertainty around a group estimate is important because a count alone does not show how precisely the underlying response rate has been estimated. A confidence interval expresses a range of values compatible with the data under the method used; no confidence interval is reported for the primary outcome. Similarly, a p-value addresses compatibility with a specified statistical model and null hypothesis, not the importance or meaning of an assay finding. No primary-endpoint p-value is reported in the registry record.
Any planning illustrations based on an observed effect are not evidence that the study was designed with a particular power, and they are not observed power. The registry's stated illustration assumptions are a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect defined as a fraction of the observed effect. These are planning assumptions, not reported features of the original study design. They do not fill the gap left by the unreported endpoint results.
9. Statistical Methods Explained
The primary outcome is binary at the subject level: each eligible subject either meets the responder definition or does not. The endpoint is then expressed as the number of responders. For a group comparison, a statistical analysis would ordinarily need to make clear both the responder count and the number of eligible subjects contributing to that count. The registry record does not report the primary counts or the relevant group denominators for the ATP endpoint, and it reports zero analyses.
What does a responder threshold represent?
The endpoint classifies a subject using assay concentrations under stimulation and medium-only conditions. The cutoff is defined relative to the percentile 95 of concentrations after medium-only stimulation in Bet v 1 BrdU+ subjects. In general, a reference percentile gives a position in a distribution; it is not the same as a direct measure of the size of a biological response. A subject just above a cutoff and a subject well above it receive the same responder classification under a binary endpoint. The registry record does not report the numerical cutoff or the underlying concentration distributions.
The assays listed are flow cytometry and multiplex assays. As a general measurement principle, assay results can be affected by biological variation, specimen handling, and measurement variability. Those considerations can influence the classification of observations near a threshold. The registry record does not report assay repeatability, validation performance, or a plan for handling measurements close to the cutoff. No conclusion about those properties can be drawn from the endpoint description alone.
How should the group comparison be understood?
In general, a comparison of binary outcomes can be presented using group-specific counts and proportions, together with an estimate of the contrast and its uncertainty. The choice of contrast and statistical method depends on the study design, the available denominators, and the analysis plan. None of the primary count results, contrast estimates, uncertainty intervals, or p-values is reported in the registry record. No statistical method for the primary comparison is reported either.
Random allocation, when used, can help balance measured and unmeasured characteristics on average. This study is explicitly non-randomized, and the registry warns that the arms are not a like-for-like control comparison. Therefore, general causal interpretations that depend on randomization are not warranted. Group differences can describe the enrolled participants, but potential selection differences and other sources of confounding remain relevant. The registry record does not report an adjusted analysis or covariates used to address such differences.
Why do over-dispersion and model choice matter?
For count data, a model may assume a particular relationship between the mean and variability. In general, over-dispersion means that the observed variation is greater than the model expects. If present and ignored, standard errors and resulting uncertainty assessments can be too small. This endpoint is a count of subjects meeting a binary criterion, so a suitable analysis would need to account for the binary outcome and the study structure rather than treating the endpoint as an unrestricted count. The registry record does not report a model, an over-dispersion assessment, or a model-checking procedure.
For a binary endpoint, estimates can also be unstable when the number of eligible participants or responders is limited. General statistical practice is to interpret the estimate alongside its uncertainty and the number of observations contributing to it. Here, those outcome details are not reported in the registry record, so precision cannot be evaluated from the registry entry.
What do the planning assumptions mean?
The stated sample-size illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It considers an effect to detect defined as a stated fraction of the observed effect. These assumptions describe a planning illustration, not the original trial's design rationale. The registry record does not report a sample-size justification for the study, and no illustration should be read as observed power or as evidence that a particular effect was detected. A planning calculation describes the sample size that might be needed under its assumptions; it does not establish the precision or evidential strength of the completed study's observed results.
In general, confidence intervals communicate the range of effect values compatible with data and a stated method. Significance tests address a specified null hypothesis under model assumptions. Neither can be interpreted without the observed data and the analysis method. The registry record does not report primary endpoint confidence intervals, tests, or a statistical analysis plan. Consequently, the methodological description supports understanding of how the endpoint was defined, but not an independent reconstruction of its results.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures, including the primary endpoint and secondary responder outcomes concerning antigen-Th2 CD4+ T cells expressing IFN-γ. One secondary outcome is described with an amended definition. The registry record does not report a multiplicity adjustment, a hierarchy of hypotheses, or a strategy for controlling the chance of false-positive findings across multiple outcomes. Without those details and the outcome results, it is not possible to determine how multiple endpoint testing was handled.
Missing outcome information is distinct from a reported finding of no effect. The primary responder counts, group denominators for the endpoint, and statistical comparisons are not reported in the registry record. Zero analyses are listed. This absence does not establish that no responders were observed; it means that responder results cannot be assessed from the registry entry.
The endpoint population is the ATP cohort of Bet v 1 BrdU+ subjects with observed PBMC proliferation after 96 hours. The registry record does not report how many enrolled participants met this definition, how many had missing assay measurements, or how exclusions were applied. It also does not report an intention-to-treat analysis, an imputation method, or sensitivity analyses for missing data. These omissions limit assessment of how representative the endpoint population is of all enrolled participants and whether missing measurements could affect the results.
In general, analysis populations and missing-data procedures matter because exclusions or unavailable measurements can alter the group being described. The record defines the intended endpoint population, but does not provide the participant flow or the details needed to evaluate missingness. Therefore, no conclusion about the impact of missing data or the robustness of analyses is supported by the registry record.
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 |
|---|---|---|---|
| Allergy Group | 0 | 40 | 0.0% |
| Control Group | 0 | 40 | 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 |
|---|---|
| Allergy Group | 0 of 40 |
| Control Group | 0 of 40 |
For the Allergy Group, the registry reports 0 participants with serious adverse events among 40 at risk and 0 participants with other adverse events among 40 at risk. For the Control Group, it reports 0 participants with serious adverse events among 40 at risk and 0 participants with other adverse events among 40 at risk. These are the posted counts in the registry record.
The death entries are not reported in the registry record; they should not be interpreted as zero deaths. The record lists no top serious adverse event terms. The available counts describe what was recorded for these groups, but the registry entry does not provide further details about event definitions, collection procedures, event timing, or follow-up. The study's stated purpose was assay development, and blood withdrawal is the listed procedure. The adverse-event figures do not provide a comparison of treatment safety because no treatment comparison is described.
In general, a zero count in a registry report means that no affected participants are listed for that category; it does not prove that an event is impossible or establish the precision of an underlying risk estimate. Interpretation also depends on the duration and completeness of event collection, which are not reported in the registry record. No broader safety conclusion should be inferred from these counts alone.
12. What the Result Does, and Does Not, Mean
The study is described as an assay-development investigation in adults with symptomatic birch pollen allergy and adults with no known allergies. It specifies a laboratory endpoint based on cytokine-expressing antigen-specific Th2 CD4+ T cells and a responder threshold. That information helps define what the investigators intended to measure and which participants were eligible for the primary endpoint population.
The registry record does not report the primary responder counts, group comparison, confidence intervals, or p-values. Therefore, it does not show the observed frequency of responders or the precision of a difference between the groups. The absence of reported results is not evidence that the groups were the same, that the assay did not detect responses, or that the endpoint was unsuccessful. It leaves those questions unanswered in the registry record.
The design also limits the interpretation of any group contrast. Participants were not randomized, the study was unmasked, and the registry cautions that the arms are not a like-for-like control comparison. A difference between groups, if outcome data were available, would be descriptive and could reflect group composition as well as allergy status. The intervention listed is blood withdrawal rather than a therapeutic treatment, and the study aim is not a treatment-efficacy question.
General statistical interpretation requires both an estimate and its uncertainty, along with clarity about the population and analysis. The registry supplies the endpoint definition and ATP population but does not report outcome estimates or uncertainty. The result therefore supports understanding of the intended assay classification, not a conclusion about the magnitude, reliability, or clinical significance of a biological difference. It also does not support medical advice or a conclusion about treatment benefit.
13. Why This Trial Matters Statistically
This study illustrates how an assay-development question can be translated into a clinical-trial registry endpoint. The endpoint is not simply a laboratory concentration: it converts stimulated assay measurements into a responder classification using a reference distribution from medium-only stimulation. That choice makes the operational definition central to interpretation. Readers need to distinguish the threshold rule from evidence about how many participants met it.
It also illustrates why analysis populations matter. The primary endpoint applies to the ATP cohort of Bet v 1 BrdU+ subjects with observed PBMC proliferation after 96 hours, rather than being described for every enrolled participant. Understanding who contributes to an endpoint is essential when interpreting a count, particularly when the registry does not report the eligible denominator or participant flow.
The design matters as well. The groups were not randomized, and the registry explicitly warns against treating them as like-for-like controls. A descriptive contrast can be useful for assay characterization, but it does not have the same interpretation as a randomized treatment comparison. The stated study purpose and the listed blood-withdrawal procedure reinforce that this is an assay-focused study, not a therapeutic efficacy trial.
Finally, the registry entry separates endpoint specification from outcome evidence. It records four outcomes but zero analyses, and the primary results are not reported in the registry record. This makes the study a useful example of why a detailed endpoint definition alone cannot answer questions about effect size, precision, or statistical evidence. Those require posted results and an analysis description.
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 statistical interpretation is that the registry record does not report the primary endpoint results. Responder counts, endpoint denominators, effect estimates, confidence intervals, and p-values are not reported. The endpoint definition can be described, but the observed pattern and its precision cannot be evaluated.
The non-randomized design and the registry's explicit warning that the arms are not a like-for-like control comparison limit causal interpretation. The record does not report adjusted analyses or details that would permit assessment of differences in participant characteristics between the groups. No masking was used, according to the registry.
The primary outcome applies to an ATP cohort defined by Bet v 1 BrdU+ status and observed proliferation after 96 hours. The registry record does not report the size of this endpoint population, participant flow, missing assay data, or reasons for exclusion. As a result, the relationship between the enrolled sample and the analyzed population cannot be assessed.
The registry record also does not report a statistical analysis plan, the method used for group comparisons, multiplicity handling, assay validation or repeatability details, or a sample-size justification for the study. Although a planning illustration is described using specified assumptions, it is not the study's own design rationale or observed power. These limits mean that the registry entry supports a precise description of the intended endpoint and design, but not an independent evaluation of outcome evidence or robustness.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Study in Allergic Adults to Support the Development of Immunological Assays — NCT01320137.
- Registry record last updated 2017-06-20; status last verified 2017-05.
- Results first posted 2017-01-31.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01320137 is a completed, non-randomized, unmasked, parallel study sponsored by GlaxoSmithKline. It enrolled 80 adults and was conducted from 2011-03-31 to a primary completion date of 2011-05-11. The study purpose was to develop and characterize immunological assays using blood samples; blood withdrawal is the listed procedure.
The Allergy Group comprised adults aged 18-45 years with symptomatic birch pollen allergy, and the Control Group comprised adults aged 18-45 years with no known allergies. The primary endpoint counts responders with antigen-specific Th2 CD4+ T cells expressing IL-4, IL-5 and/or IL-13 at Day 0, using a threshold based on medium-only concentrations.
The endpoint population is defined as ATP Bet v 1 BrdU+ subjects with observed PBMC proliferation after 96 hours. The registry lists four outcome measures and zero analyses. Primary outcome results and statistical comparisons are not reported in the registry record. The adverse-event entries list no affected participants in the reported categories for either group; death counts are not reported in the registry record.