SPT for Sensitization of Collagen Dressing: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for SPT for Sensitization of Collagen Dressing (NCT06271993), a na na study. The primary outcome is Wheal Measurement.

2. Clinical Question

The study asks whether ColActive Plus Collagen Matrix Dressing induces skin sensitization, described in the registry record as contact allergy, when applied by skin prick test to healthy human subjects. The test product was applied using a UniTest PC pain-control device, alongside positive and negative controls. The registry describes skin response assessment by an allergist after application.

The primary outcome is titled Wheal Measurement. It records the wheal at each test site in millimeters, with a larger wheal, at least 3 mm, described as associated with sensitization. The primary outcome timeframe is 15–20 minutes following application. The study summary also describes evaluation at 15 minutes, 6 hours, and 24–48 hours; those time points should not be mistaken for additional reported primary outcome results.

The registry record does not report the observed wheal measurements, a summary of the product response, or a statistical analysis answering the study question. It therefore supports a description of the question and measurement approach, but not a conclusion about whether sensitization was observed.

3. Trial Design

NCT06271993 is listed as a completed, single-group study of ColActive Plus Collagen Matrix Dressing. The registry lists the study phase as not applicable, allocation as not applicable, and masking as none. The enrollment is 27. The listed start date is 2024-02-08, and the primary completion date is 2024-02-16. These dates describe the registry record; they do not provide the timing of individual participant visits.

The arm is described as collagen wound dressing with positive and negative controls. Participants had the test dressing, histamine, and saline with glycerin applied to volar forearm skin. These controls help frame the skin response observed during testing, but they do not make the study a randomized, between-group comparison. The registry explicitly identifies the design as nonrandomized and says the arms are not a like-for-like control comparison.

The brief summary describes an allergist evaluating skin response at 15 minutes, 6 hours, and 24–48 hours after application. The primary endpoint itself has a stated timeframe of 15–20 minutes following application. The record does not explain the relationship between those descriptions in detail, so the later assessments should not be treated as additional primary endpoint measurements.

There are 3 outcome measures listed and 0 analyses listed. The registry record does not report a statistical analysis plan, a sample-size justification, a recruitment target rationale, interim analyses, or an analysis population for the primary endpoint. The record also does not report whether all enrolled participants completed every assessment. These omissions limit what can be reconstructed about how the investigators intended to summarize the wheal observations or handle incomplete measurements.

The serious and other adverse-event figures use a risk set of 22 in the listed group, whereas overall enrollment is 27. The registry does not report why those counts differ. The difference should not be interpreted as evidence about completion, eligibility, or follow-up without further information.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

Reasons for not completing this period:

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.

6. Primary Endpoint

The registry lists the primary outcome as Wheal Measurement, measured over 15-20 minutes following application.

The primary endpoint is Wheal Measurement, recorded in millimeters at each test site. A wheal is the raised skin response assessed following the skin prick procedure. The registry specifies the mean as the endpoint parameter and the full range as its dispersion measure. It gives the primary measurement timeframe as 15–20 minutes following application.

This measurement is used to characterize the immediate skin response at the test site. The registry description states that a larger wheal, at least 3 mm, is associated with sensitization. That association explains why wheal size is relevant to the study question; it does not itself establish that a participant has contact allergy, nor does the threshold replace clinical interpretation.

The study summary also describes assessment at 15 minutes, 6 hours, and 24–48 hours. However, only the wheal measurement with the 15–20-minute timeframe is specified as the primary outcome. The registry does not report the observed mean, full range, individual measurements, or the number of evaluable participants for this endpoint. It also does not report whether a particular response was classified as sensitization in the study results. Consequently, the endpoint definition can be described, but its observed distribution and the result of the primary question cannot be assessed from the registry record.

In general, reporting both a mean and a full range can show a central summary alongside the minimum-to-maximum spread. A range is sensitive to the most extreme observations and does not describe how values are distributed between those extremes. Without the actual endpoint values, neither the mean nor the range can be interpreted for this study.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry identifies this as a single-group study, with allocation listed as not applicable and masking listed as none. In general, a single-group design describes observations made within one study group rather than a randomized comparison between separate groups. Here, the product and both controls are applied within the testing procedure. The registry specifically cautions that the arms are not a like-for-like control comparison. Accordingly, the design description does not support treating the control applications as randomized comparator arms or interpreting the study as a conventional two-arm treatment-effect trial.

What does the primary measure summarize?

The primary measure is wheal size in millimeters. The registry names the mean as the summary parameter and the full range as the dispersion measure. In general, a mean summarizes the arithmetic center of a set of measurements, while a full range reports the smallest and largest observed values. A range can help show the span of observations, but it does not reveal how many observations lie near either endpoint or whether the distribution is concentrated or uneven. Those interpretations require actual measurements, which are not reported in the registry record.

The registry states that a larger wheal, at least 3 mm, is associated with sensitization. This is a description of the endpoint's clinical interpretation in the record, not a reported finding. Without the measured values and the analysis rule used to classify responses, it is not possible to establish how the threshold was applied or how many participants had responses meeting it.

How should time points be understood?

The primary endpoint timeframe is 15–20 minutes following application. The brief summary separately describes evaluations at 15 minutes, 6 hours, and 24–48 hours. In general, a time point specifies when a measurement is intended to be made; measurements at different times may reflect different stages of a response and should not be assumed interchangeable. The record does not provide separate results for those assessment times or explain whether later observations were outcomes, safety assessments, or part of another evaluation. The primary endpoint should therefore be read according to its own stated timeframe.

What can be inferred from a missing analysis?

The registry lists 0 analyses. In general, a statistical analysis specifies how observed data are converted into estimates, how missing observations are handled, and whether uncertainty or hypothesis tests are calculated. The record does not report such a plan for wheal measurement. It gives no endpoint estimate, confidence interval, p-value, or participant-level distribution. No inferential conclusion can be reconstructed from the endpoint definition alone.

A confidence interval, in general, expresses uncertainty around an estimated quantity under specified statistical assumptions. It does not guarantee that the true value lies within a particular interval, and its interpretation depends on the method and data. Since no confidence interval or underlying endpoint summary is reported, the precision of the primary result cannot be evaluated.

What do the planning illustrations represent?

General sample-size planning illustrations use assumptions about the effect to detect, statistical significance level, allocation, and a model for the data. The registry's planning description says the illustrations use the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. These are planning assumptions, not evidence that the actual study used a two-arm design or enrolled participants according to that calculation. The study itself is listed as single group with allocation not applicable.

Sample-size illustrations are planning calculations, not observed power. In general, observed power calculated after a study is completed does not provide a useful substitute for interpreting the estimated effect and its uncertainty. The registry record does not give a primary endpoint effect estimate, and no planning illustration value is reported in the record. The described assumptions therefore cannot establish the study's actual sample-size rationale, whether the enrollment was adequate for a prespecified target, or the precision of the endpoint result.

Why do distributional assumptions matter?

The planning description refers to a normal approximation. In general, a normal approximation treats a statistic as having a distribution that can be approximated by a bell-shaped curve under the method's conditions. Whether that approximation is suitable depends on the data and design. Wheal measurements may have a distribution that cannot be assessed without the observed values. The registry does not report diagnostics, an alternative model, or a method for handling unusually large or small measurements.

Over-dispersion is a general concern when observed variability is greater than a model expects. In such cases, model-based standard errors or intervals can be too narrow if the excess variability is ignored. This is a general statistical consideration, not a reported feature of this study: the registry provides neither the endpoint values nor a fitted model from which over-dispersion could be assessed.

Because the record contains no endpoint analysis, recalculation from posted summary statistics is not possible. There is no sponsor analysis to compare with a recalculated estimate, and no basis for choosing an adjustment or inferential model. The statistically responsible interpretation is to distinguish the planned measurement and generic planning assumptions from an observed result, which is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 3 outcome measures and 0 analyses. The outcome measure count indicates that multiple outcomes are listed, but their full definitions and any analysis hierarchy are not included in the available record. It is therefore not possible to determine whether one outcome was formally prioritized for inference beyond the primary designation, whether any secondary outcomes were tested, or whether multiplicity adjustments were planned or applied. The record does not report a multiplicity strategy.

In general, multiplicity arises when several hypotheses or outcomes are examined. Testing many outcomes can increase the chance of observing an apparently notable result by chance if the analyses are not accounted for. Different approaches can address that issue, but no particular approach should be attributed to this study without a report of the statistical plan or analysis. Since no analyses are listed, there are no reported p-values to assess for multiplicity.

Missing-data methods are not reported in the registry record. The record does not state whether any wheal measurements were missing, how incomplete observations were treated, or whether participants with incomplete assessments were excluded from a particular analysis. It also does not identify the primary endpoint analysis population. The enrollment of 27 does not establish that all 27 contributed a primary outcome measurement.

The adverse-event group lists 22 participants at risk, compared with 27 enrolled overall. The reason for this difference is not reported in the registry record, and the safety risk set should not be substituted for an endpoint analysis denominator. No assumptions about withdrawal, eligibility, attendance, or data completeness can be made from these counts alone.

In general, complete-case analysis, imputation, and other missing-data approaches rely on assumptions about why data are absent. Without information about missing observations and the planned analysis, those assumptions cannot be evaluated. The record also does not report analysis populations such as all enrolled participants or a defined subset. These omissions limit interpretation of both the endpoint and the completeness of the reported results.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists 0 serious adverse events among 22 participants at risk in the group. It also lists 0 other adverse events among the same 22 participants at risk and 0 deaths. No serious adverse-event terms are listed. These figures describe the safety entries in the registry record; they do not supply the primary wheal measurement result.

The risk set of 22 is not the same as the overall enrollment of 27. The registry does not report why these counts differ, so the smaller risk-set count cannot be interpreted as a particular number of withdrawals, exclusions, or participants lost to follow-up. The adverse-event counts should be read using their stated risk-set denominator and not assumed to cover every enrolled participant.

In general, observing no events in a reported group does not establish that an event is impossible or that the underlying risk is zero. The precision of a safety estimate depends on the amount and duration of observation and the completeness of event ascertainment. Those details are not reported in the registry record. The zero counts describe what is recorded, not proof that no event could occur in other people or settings.

The record does not report event definitions, collection procedures, follow-up duration for safety, or a comparison against a separate control group. The safety entries should therefore be interpreted narrowly: no serious or other adverse events and no deaths are listed for the group of 22 participants at risk.

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

The study is designed to examine skin sensitization after skin prick application of ColActive Plus Collagen Matrix Dressing in healthy human subjects. Its primary outcome is wheal measurement in millimeters, defined as a mean with full range at 15–20 minutes following application. The registry description associates a larger wheal, at least 3 mm, with sensitization. These details explain what the study set out to assess and how the primary response was characterized.

They do not establish what response was observed. The registry record does not report the primary wheal values, a summary estimate, a classification of sensitization, or an analysis answering the primary question. It is not possible to infer from the absence of an outcome result that no sensitization occurred, or that sensitization did occur. The correct interpretation is that the primary result is not reported in the registry record.

The study's single-group design and the application of positive and negative controls should also be kept distinct. Controls used within the skin prick procedure provide context for interpreting responses, but they are not described as randomized, independent comparison groups. The study is not reported as a randomized trial comparing the dressing with a separate control arm.

The registry reports 27 participants enrolled and lists 22 at risk for adverse-event reporting. It does not explain the difference or provide the number with evaluable primary endpoint measurements. This means neither the endpoint denominator nor the completeness of assessments can be established from the listed enrollment alone.

The adverse-event record lists no serious adverse events, no other adverse events, and no deaths among the 22 participants at risk. These entries are limited observations in the registry and do not determine the primary sensitization outcome. In general, zero recorded events in a study group are not evidence that risk is absent in every setting.

Overall, the record supports a description of the test procedure, endpoint definition, design, and recorded safety counts. It does not support a statistical conclusion about the magnitude, frequency, or precision of the skin response. It also does not establish a comparative effect, because there is no like-for-like randomized control comparison reported.

13. Why This Trial Matters Statistically

This study illustrates an important distinction between a defined endpoint and a reported result. A registry can describe what investigators intend to measure—in this case, mean wheal size in millimeters, with full range, at 15–20 minutes—without reporting the actual observations or an analysis. Readers need both the measurement definition and the result to evaluate the stated research question. Here, the result is not reported in the registry record.

The design also matters to interpretation. The product, positive control, and negative control are applied within a single-group procedure. That arrangement is not equivalent to randomized allocation between independent groups. Recognizing this prevents a reader from treating the controls as if they established a conventional comparative treatment effect.

Denominators are another statistical issue highlighted by the record. Overall enrollment is 27, while the adverse-event risk set is 22. The record does not explain the difference. Reporting the relevant population for each analysis is necessary for judging how many observations contribute to an estimate and whether results cover the enrolled group. The primary endpoint denominator is not reported.

The registry lists 3 outcome measures but 0 analyses. This underscores why outcome registration and statistical reporting serve different purposes. Outcome definitions indicate what is assessed; analyses communicate how observed data were summarized and how uncertainty was evaluated. Without the latter, a reader cannot assess the estimate, precision, missing-data handling, or multiplicity.

Finally, zero recorded adverse events are descriptive, not proof of zero risk. The safety figures are useful as a report of recorded events in the stated risk set, while their interpretation remains bounded by the information on follow-up and ascertainment, which is not reported. The trial therefore matters statistically as an example of why design, denominators, outcome results, and analysis details must be read together, while keeping unreported findings separate from negative findings.

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 direct limitation is that the primary outcome result is not reported in the registry record. Although the endpoint is defined as mean wheal measurement with full range, no measurements, estimate, or endpoint analysis are listed. The central question about sensitization therefore cannot be answered statistically from the record.

The registry describes assessments at 15 minutes, 6 hours, and 24–48 hours in the study summary, while the primary outcome timeframe is 15–20 minutes. It does not give results at these times or clarify how each assessment contributes to the outcome set. The endpoint denominator and the number of participants with complete measurements are also not reported.

The study is single group, with no allocation and no masking. The test product and controls are applied as part of the procedure, but the registry cautions that the arms are not a like-for-like control comparison. The design does not provide a randomized between-group estimate. No analysis plan, prespecified statistical model, interim analysis information, or sample-size justification is reported.

Although 27 participants are listed as enrolled, adverse-event reporting uses a risk set of 22. The reason for this difference is not reported in the registry record. It cannot be assumed that the same participants contributed to the primary outcome or that the safety count represents the full enrolled group.

The record lists 3 outcome measures but no analyses. It does not report how missing observations were treated, whether any outcomes were adjusted for multiple testing, or how the mean and range were calculated from the observed data. These limitations prevent assessment of the outcome distribution, precision, and robustness. The listed zero adverse-event counts are similarly limited by the absence of reported safety follow-up and ascertainment details.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: SPT for Sensitization of Collagen Dressing — NCT06271993.
• Registry record last updated 2024-09-19; status last verified 2024-08.
• Results first posted 2024-09-19.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

NCT06271993 is a completed, single-group skin prick test study of ColActive Plus Collagen Matrix Dressing in healthy human subjects. Enrollment is 27. The registry lists allocation as not applicable and masking as none. The study summary describes application of the product, histamine, and saline with glycerin to volar forearm skin, with skin response evaluation by an allergist.

The primary outcome is Wheal Measurement in millimeters, summarized as a mean with full range at 15–20 minutes following application. The registry describes a larger wheal, at least 3 mm, as associated with sensitization. It lists 3 outcome measures and 0 analyses, but no primary wheal results or analysis are reported in the registry record.

The safety group lists 22 participants at risk, with 0 serious adverse events, 0 other adverse events, and 0 deaths. The reason the risk set differs from overall enrollment is not reported. The available record defines the study question and measurement approach but does not provide a statistical result for the primary question.