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 Evaluation of an Experimental Treatment, Intradermal Human Fcγ1-Fel d1 Fusion Protein (GFD), for Cat Allergy (NCT01292070), a na early/phase 1 study. The primary outcome is Difference in the Doses of GFD and CAT Required to Elicit a Cutaneous Reaction Demonstrated by a Wheal Greater Than or Equal to 10 mm With Surrounding Erythema.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01292070 |
| Phase | EARLY/Phase 1 |
| Condition | Cat Allergy |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| 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
Cat-allergic healthy volunteers. The registry lists an enrollment of 4, and the primary outcome description refers to the first 4 participants dosed.
Intervention
Intradermal human Fcγ1-Fel d1 fusion protein (GFD), an experimental protein containing cat allergen.
Comparator
Standardized cat hair allergenic extract (CAT). Each participant served as their own control: the left arm received CAT and other controls, while the right arm received GFD. The registry also lists histamine prick and intradermal diluent controls.
Primary question
What doses of GFD and CAT were required to elicit a wheal of at least 10 mm with surrounding erythema, and how did those doses differ? The endpoint was intended to be assessed up to 3 hours after the last GFD injection, but it was not evaluated.
The study also aimed to assess safety and tolerability and to examine whether GFD could block a skin reaction to cat allergen compared with allergen alone. The registry describes the two proteins as eliciting comparable reactivity in the first 4 participants dosed. It states that the trial was discontinued for futility, leaving the planned dose-difference endpoint unevaluated. Consequently, the registry does not report an estimated dose difference or a statistical comparison of that endpoint. The question is therefore a description of the trial’s intended comparison, not a result establishing a dose difference or a blocking effect.
3. Trial Design
The registry classifies the study as early phase 1 and lists its official title as a dose-escalating Phase 0 study. It was a single-group study with no masking and no randomized allocation. The registry lists enrollment of 4 and a terminated status. The recorded study dates are 2011-03 for start and 2011-04 for primary completion.
The design used each participant as their own control. According to the arm description, the left arm received the control protein conditions, including histamine prick, intradermal diluent, and intradermal CAT; the right arm received GFD. This arrangement makes the comparison within participant rather than between separately assigned groups. The registry does not describe random assignment of treatments to sides, and the recorded allocation is NA. Thus, the GFD and CAT conditions should not be described as randomized groups or as a conventional parallel-arm trial.
The primary outcome was the difference in doses of GFD and CAT required to produce a wheal meeting the stated size threshold with surrounding erythema. The assessment timeframe was up to 3 hours after the last GFD injection. The registry reports that comparable reactivity was observed in the first 4 participants dosed and that the trial was discontinued for futility. It also explicitly states that the primary endpoint was not evaluated. A dose-escalation schedule, stopping boundary, and detailed conduct of any futility assessment are not reported in the registry record.
Four interventions are listed: GFD, standardized cat hair allergenic extract, histamine prick, and intradermal diluent. These include the experimental condition and control conditions; they do not represent independent randomized groups. The single-group design and limited enrollment mean that the registry results are descriptive rather than a completed estimate of the planned primary comparison.
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 | Control (CAT) - Experimental (GFD) |
|---|---|
| STARTED | 4 |
| COMPLETED | 4 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: The experimental protein (human Fcgamma1-Fel d1 fusion protein (GFD)) and the control protein (standardized cat hair allergenic extract (CAT)) elicited comparable reactivity in the first four participants dosed; thus, the trial was discontinued for futility and the primary endpoint was not evaluated
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
| Characteristic | Unit | Control (CAT) - Experimental (GFD) |
|---|---|---|
| Participants analysed | 4 | |
| Age, Continuous | years | 25.3 (SD 2.4) |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 4 |
| Age, Categorical: >=65 years | Participants | 0 |
| Sex: Female, Male: Female | Participants | 2 |
| Sex: Female, Male: Male | Participants | 2 |
| Region of Enrollment: Australia | participants | 4 |
6. Primary Endpoint
The registry lists the primary outcome as Difference in the Doses of GFD and CAT Required to Elicit a Cutaneous Reaction Demonstrated by a Wheal Greater Than or Equal to 10 mm With Surrounding Erythema, measured over up to 3 hours after the last injection of GFD.
| 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 intended to compare the doses of GFD and standardized cat hair allergenic extract (CAT) needed to elicit a wheal of at least 10 mm with surrounding erythema. The assessment was specified for up to 3 hours after the last GFD injection. In this context, the endpoint uses a visible skin response as an indicator of cutaneous reactivity and expresses the comparison in terms of the dose required to reach a defined response threshold.
General: A threshold-based endpoint can make a response rule explicit and can support a direct comparison of the amount of each test substance needed to reach that rule. Measuring doses rather than only recording whether a reaction occurred can be useful when the response is assessed across escalating doses. The registry does not report the detailed dose levels, measurement procedures, or criteria for evaluating the surrounding erythema.
The endpoint was not evaluated. The registry says that GFD and CAT elicited comparable reactivity in the first 4 participants dosed and that the trial was discontinued for futility. It therefore provides no endpoint estimate, dose difference, uncertainty interval, or endpoint-specific test. The intended threshold should not be mistaken for an observed result: it defines what the study planned to measure, not a reported dose or reaction outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The main result recorded is that GFD and CAT elicited comparable reactivity in the first 4 participants dosed. The registry states that the trial was discontinued for futility and that the primary endpoint was not evaluated. These statements describe why the planned dose comparison is unavailable; they do not supply a numerical estimate of the difference between the doses needed to reach the skin-reaction threshold.
Without an evaluated endpoint, there is no reported effect estimate or confidence interval for the primary question. There is also no reported endpoint-specific hypothesis test or p-value. The result should therefore be read as a registry statement about observed comparability in the first participants, not as a quantified estimate of equivalence. A claim of equivalence would ordinarily require a defined margin and an analysis designed to assess whether uncertainty is sufficiently narrow to exclude differences outside that margin; such details are not reported in the registry record.
The trial used a within-participant arrangement, with GFD on the right arm and control conditions, including CAT, on the left. This avoids treating the conditions as if they were assigned to separate randomized groups, but the fixed side assignment means that the record does not describe randomized allocation of sides. The registry does not report an adjusted analysis or a method for accounting for side-specific response. No comparison should be inferred beyond what the record states.
The safety record lists 4 participants at risk for serious adverse events and 0 with a serious adverse event. It lists 4 at risk for other adverse events and 1 with an other adverse event. These counts are descriptive. The registry does not list a serious adverse-event term, and deaths are not reported in the registry record. The small enrolled group and the study’s termination limit how much these counts can establish about safety; the absence of a recorded serious event in this group does not establish that serious events cannot occur.
In short, the registry supports a narrow account: comparable reactivity was reported in the first 4 dosed participants, the study stopped for futility, and the primary dose-difference endpoint was not evaluated. The size and precision of any underlying difference, and the formal statistical basis for the futility decision, are not reported in the registry record.
9. Statistical Methods Explained
The registry describes a single-group study in which each participant served as their own control. GFD was administered on the right arm, while control conditions, including CAT, were applied on the left arm. This is a within-participant comparison, not a randomized comparison between separate groups. The allocation field is NA and masking is none. The registry does not report random assignment of sides or masking of participants or investigators.
What the primary endpoint would compare
The planned endpoint was a difference between the doses of GFD and CAT required to produce a wheal of at least 10 mm with surrounding erythema. The timeframe was up to 3 hours after the last GFD injection. General: A dose-threshold endpoint converts a graded response into a comparison of the amount of each substance associated with a prespecified response. In a dose-escalation setting, the threshold is the decision rule for identifying a dose that elicits the defined reaction. The exact escalation schedule and the measurement procedures are not reported in the registry record.
The registry explicitly says that the endpoint was not evaluated. It reports comparable reactivity for GFD and CAT in the first 4 participants dosed and says the trial was discontinued for futility. Accordingly, there is no reported estimate of the dose difference, no measure of its precision, and no endpoint test to interpret. The registry does not describe a statistical model for paired observations or any method for handling participant-level variability.
What uncertainty measures would mean
General: A confidence interval gives a range of values compatible with an estimate under the assumptions of the analysis. Its width reflects precision: a wider interval is less informative about the size of the effect than a narrower one. A confidence interval is not a guarantee that the true effect lies within its limits. No confidence interval for the primary endpoint is reported in the registry record, so the precision of the planned dose comparison cannot be assessed from the endpoint results.
General: A hypothesis test evaluates how compatible the observed data are with a specified null hypothesis under a statistical model. A p-value is not the probability that the null hypothesis is true, and it does not quantify the size or clinical importance of an effect. Because the primary endpoint was not evaluated, the registry does not provide a corresponding test or p-value. The criterion used to label the study futile is also not reported in the registry record. The term should not be taken to imply a particular statistical stopping boundary or interim-analysis procedure.
How to interpret planning illustrations
General: Sample-size calculations are planning exercises based on assumptions about the target effect, variability, allocation, and testing procedure. They are not observed power, and a planning estimate does not show what the study’s results would have been with a different enrollment. The stated planning assumptions for illustrations are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and effects defined as stated fractions of the observed effect. Those assumptions are distinct from the registry’s single-group, within-participant design. Such illustrations should therefore be read as planning scenarios, not as the trial’s actual design or as evidence that the endpoint was analyzed.
General: Over-dispersion occurs when observed variability exceeds what a statistical model assumes. If it is ignored, standard errors may be too small and confidence intervals too narrow, making results appear more precise than they are. The registry does not report a count model or other model for the primary endpoint, so over-dispersion is not an identified analysis issue for a reported endpoint result. More broadly, the analysis methods, variance assumptions, and statistical software are not reported in the registry record.
The registry lists one outcome measure and no recorded analyses. The absence of a reported analysis is particularly important because the primary endpoint is expressly described as not evaluated. There is no basis in the registry record for reconstructing an endpoint estimate, testing a treatment difference, or assessing its precision. The reported comparison is descriptive, and the reasons and statistical criteria behind the futility decision remain unspecified.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure, the primary comparison of doses required to elicit the defined skin reaction. It does not report an analysis for that endpoint, and it states that the endpoint was not evaluated. The registry does not describe a multiplicity adjustment, a hierarchy of outcomes, or a strategy for controlling false-positive findings across multiple tests. The presence of several control conditions does not, by itself, establish how many statistical comparisons were planned or how they would be handled.
General: Multiplicity arises when several hypotheses or outcomes are tested, because repeated testing can increase the chance of a nominally positive result when no corresponding effect exists. Procedures such as adjusted significance thresholds or prespecified testing sequences can address that issue, but the selected approach depends on the analysis plan. Such a plan is not reported in the registry record, so the multiplicity approach cannot be assessed.
The endpoint’s non-evaluation should not automatically be treated as ordinary missing outcome data. The registry attributes it to discontinuation for futility after comparable reactivity in the first 4 participants dosed. It does not report participant-level endpoint values, the reason any individual measurement might be unavailable, or a missing-data method. It also does not describe an analysis population, such as an intention-to-treat or per-protocol population. The registry record therefore does not support conclusions about how missing measurements were handled or which participants would have been included in a formal endpoint analysis.
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 |
|---|---|---|---|
| Control (CAT) - Experimental (GFD) | 0 | 4 | 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 |
|---|---|
| Control (CAT) - Experimental (GFD) | 1 of 4 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Control (CAT) - Experimental (GFD) |
|---|---|---|
| Rhinitis | Infections and infestations | 1 of 4 |
The registry lists 4 participants at risk for serious adverse events and 0 with a serious adverse event. For other adverse events, it lists 4 at risk and 1 affected. The serious adverse-event terms list is empty, and deaths are not reported in the registry record. The registry does not identify the type or timing of the other adverse event in the information available for these results.
These are counts in a small study group, not estimates of event rates that can be generalized to a broader population. General: An observed count describes what was recorded among participants at risk; it does not establish the probability of an event in other people or rule out events that were not observed. A zero count is not proof of zero risk. The registry does not report further details about event severity, relationship to treatment, duration, or follow-up for these figures. The figures should therefore be read narrowly as the recorded safety counts, without inferring the nature of the event or a causal relationship to GFD.
12. What the Result Does, and Does Not, Mean
The record documents a small, terminated study of intradermal GFD in cat-allergic healthy volunteers. It reports comparable reactivity with GFD and CAT in the first 4 participants dosed and states that the study was discontinued for futility. The intended primary comparison was the difference in doses needed to elicit a defined wheal with surrounding erythema, but the registry says that endpoint was not evaluated.
That distinction matters: a reported observation of comparable reactivity is not the same as a completed statistical estimate showing that the two conditions are equivalent. No dose difference, confidence interval, or endpoint test is reported. The registry also does not report the futility rule or the statistical criteria used to stop the study. The result therefore cannot establish how large a difference might have been compatible with the observed data or how precisely the intended contrast could be estimated.
The safety counts are limited to 0 serious adverse events among 4 at risk and 1 other adverse event among 4 at risk. They do not establish the broader safety profile of GFD, and the registry does not identify the other adverse event in these results. The counts are descriptive and should not be interpreted as proof that an event cannot occur.
The record does not establish that GFD blocked a skin reaction, nor does it establish the size of any difference in reactivity compared with CAT. It documents the study’s intent, the early observation of comparable reactivity, the stated reason for discontinuation, and the absence of an evaluated primary endpoint. Any stronger inference would require outcome and analysis information that is not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates why the distinction between an intended endpoint and an evaluated endpoint is central to statistical interpretation. The registry defines a dose-based primary question, but then states that the endpoint was not evaluated after the first 4 participants dosed showed comparable reactivity. Without an endpoint estimate and its uncertainty, readers cannot quantify the difference the study was designed to examine.
The record also shows why design details matter. Participants served as their own controls, with GFD on the right arm and CAT and other controls on the left. This is not a randomized comparison between independent groups. The fixed side arrangement and absence of reported masking are relevant context when interpreting a descriptive statement about comparable responses. The registry does not report an analysis that accounts for paired observations or potential side effects.
Futility is a statistical and design concept, but the label alone does not reveal the rule used. The registry does not report an interim-analysis plan, stopping boundary, or other criterion behind discontinuation. Treating the term as if it identified a particular statistical procedure would go beyond the record.
Finally, the small enrollment and limited safety counts demonstrate the difference between observing no serious events in a study and establishing a well-characterized safety profile. The registry lists 0 serious adverse events among 4 at risk, but that count cannot characterize uncommon outcomes or provide broad assurance. The study is statistically informative chiefly as an example of how early termination can leave a planned comparison unresolved, while still yielding limited descriptive observations.
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 primary limitation is that the planned dose-difference endpoint was not evaluated. Although the registry reports comparable reactivity in the first 4 participants dosed, it provides no endpoint estimate, uncertainty interval, or statistical test. The magnitude and precision of the intended comparison are therefore not available.
Enrollment was 4, and the registry describes the trial as terminated. The safety counts are consequently based on a small group: 4 participants at risk for serious adverse events and 4 at risk for other adverse events. The registry does not identify the other adverse event in these results, and deaths are not reported in the registry record.
The study was unmasked and used a fixed side arrangement, with GFD on the right arm and control conditions on the left. Allocation is recorded as NA. The registry does not describe randomization of sides, masking procedures, or an analysis addressing possible side-related differences. The design should therefore not be interpreted as a randomized comparison.
The registry does not report the dose-escalation schedule, a futility boundary, interim-analysis procedures, detailed endpoint measurement methods, statistical analysis methods, missing-data handling, or analysis populations. It also does not report the basis for the sample-size target. These omissions prevent assessment of the operating characteristics of the planned analysis or reconstruction of the reason the endpoint was not evaluated beyond the stated discontinuation for futility.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety Evaluation of an Experimental Treatment, Intradermal Human Fcγ1-Fel d1 Fusion Protein (GFD), for Cat Allergy — NCT01292070.
- Registry record last updated 2014-02-20; status last verified 2014-01.
- Results first posted 2014-02-20.
- 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 an early-phase study, titled as a dose-escalating Phase 0 study, of intradermal GFD in cat-allergic healthy volunteers. It lists enrollment of 4, no masking, a single-group design, and terminated status. Participants served as their own controls, with GFD administered on the right arm and CAT and other control conditions on the left.
The primary endpoint was the difference in doses of GFD and CAT required to elicit a wheal of at least 10 mm with surrounding erythema, assessed up to 3 hours after the last GFD injection. The registry reports comparable reactivity in the first 4 participants dosed, discontinuation for futility, and non-evaluation of the primary endpoint. Safety counts were 0 serious adverse events among 4 at risk and 1 other adverse event among 4 at risk. No endpoint estimate or statistical analysis is reported in the registry record.