A Pilot Study to Evaluate a Temporary Skin Substitute (Spincare® Matrix) for Wound Healing in RDEB Patients: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Pilot Study to Evaluate a Temporary Skin Substitute (Spincare® Matrix) for Wound Healing in RDEB Patients (NCT05944250), a randomized na study. The primary outcome is Number of Wounds With Greater Than 90% Wound Closure at 4 Months.

2. Clinical Question

The study was a pilot evaluation of the suitability of Spincare matrix for RDEB wounds, including assessment of wound healing properties, safety and tolerability. Its primary endpoint focuses on a high threshold of wound closure reached within a defined period. The registry wording also refers to comparison of the duration of wound closure, while specifying the endpoint as the number of wounds reaching greater than 90% closure within 4 months. These descriptions do not give a time-to-event estimate; the posted primary results are counts of wounds.

The design includes both a randomized period and an optional open-label extension. In the randomized period, each eligible wound site was assigned to matrix treatment or standard-of-care dressings. Eligible participants could later choose to enter the extension, in which previously randomized and new wounds could be treated with matrix. The extension had no control or randomization according to its description, so it addresses a different question from the randomized wound comparison.

3. Trial Design

This was a randomized, sequential-model pilot study sponsored by Stanford University. The registry lists the study phase as not applicable and masking as none. The study enrolled 6 participants and is listed as completed. Its dates are 2023-09-19 for study start and 2024-08-14 for primary completion.

The randomized period used wounds as the units assigned to treatment. Investigators were to examine the whole body, identify target wound areas, and randomize eligible wound sites to Spincare matrix or standard-of-care wound dressings. The description specifies at least 6 wounds, or 3 wound pairs. The registry’s primary results list 3 matrix-treated wounds and 3 standard-of-care-treated wounds. These wound counts should not be read as participant counts: the study enrollment was 6 participants, while the primary outcome is a wound count.

The intervention is a temporary matrix dressing applied using the Spincare device. The registry characterizes it as a non-invasive, non-therapeutic electrospun nanofibrous matrix. The comparator was standard-of-care wound dressings. Because masking was listed as none, the study was not described as masked. No further details about how treatment assignment was generated or concealed are reported in the registry record.

An optional open-label phase lasting 4 months was described for participants who were eligible and chose to take part. During this extension, participants could treat previously randomized wounds, whether previously treated or control wounds, as well as new wounds, up to a maximum of 10 individual wounds. The description states there would be no control or randomization in this phase. One participant was listed as at risk in the open-label matrix safety group; that safety count does not establish the number of participants who entered the extension overall.

The primary endpoint population is described as participants with month 4 data. The number of participants contributing month 4 data, and the relationship between those participants and the wound counts in the primary comparison, are not reported in the registry record. Further protocol details, including sample-size justification and any planned interim analyses, 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: On Day 0, the investigator conducted an in-person full body skin examination and collected wound measurements to verify eligibility. The participant's wounds were assessed for signs of infection, and target wound areas were identified. Wounds that were actively infected with pus were excluded before randomization and the application of the matrix.

Randomized Period (4 Months)

Open Label Period (4 Months)

Analysis population for the primary outcome, as defined in the registry: Participants with month 4 data

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: Patients aged 6 to 65 years old with a clinical and/or genetic diagnosis of recessive dystrophic epidermolysis bullosa. This is a pilot study in 6 subjects where wounds were randomized 1:1 to matrix application or no treatment (control).

6. Primary Endpoint

The registry lists the primary outcome as Number of Wounds With Greater Than 90% Wound Closure at 4 Months, measured over Baseline to month 4 of the randomized phase.

The primary endpoint is the number of wounds with greater than 90% wound closure at 4 months. The registry describes the timeframe as baseline to month 4 of the randomized phase and identifies the outcome unit as wounds. In practical terms, the endpoint counts wounds that crossed the stated closure threshold by the specified follow-up point; it does not report an average percentage of closure or a time-to-closure estimate.

A threshold-based count can make the result easier to interpret as the number of wounds reaching a prespecified degree of closure within a period. It also discards detail: a wound just below the threshold and one with much less closure both do not count as reaching the endpoint, while wounds above the threshold are counted together. General statistical consideration: this kind of endpoint can be useful when a clinically meaningful state is expressed as reaching a target, but the count alone does not describe the full distribution of wound healing.

The registry’s endpoint description says the comparison concerns duration of wound closure, but the named primary outcome and posted values are counts of wounds reaching greater than 90% closure within 4 months. No event times, duration summaries, or time-to-event analysis results are reported in the registry record. The primary result should therefore be interpreted as a count comparison, not as a measure of how long closure lasted.

The posted counts are 0 matrix-treated wounds and 3 standard-of-care-treated wounds, with 3 wounds listed in each group. The registry specifies participants with month 4 data as the primary endpoint population, but does not report the participant-level details or missing wound outcome counts underlying that population description.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry reports a two-sided t-test for the primary comparison. General statistical explanation: a t-test evaluates a contrast between group summaries using an estimate of variability and a reference distribution. A two-sided test allows evidence in either direction to count against the null hypothesis. The test’s interpretation depends on its assumptions and on how the observations were defined. The registry does not report further detail about the exact t-test specification or how it accounted for the fact that wounds, rather than participants, were assigned to treatment.

What does the p-value tell us?

The reported p-value is 0.21. In general, a p-value measures how unusual data at least as incompatible with a null model as the observed data would be, assuming that model and the test’s assumptions are correct. It does not give the probability that a treatment is effective, the probability that the null hypothesis is true, or the size of a difference. A p-value alone also does not indicate precision. The registry reports no confidence interval for the primary comparison, so the range of effect values compatible with the data is not available from the posted inferential result.

The registry gives the primary results as counts: 0 wounds with greater than 90% closure in the matrix group and 3 in the standard-of-care group, with 3 wounds in each group. The outcome is a count of wounds meeting a threshold. General statistical explanation: for count outcomes, the choice of model often depends on how counts arise, their variability, and whether observations are independent. A t-test may be used for group comparisons under particular assumptions, but a small number of wound-level observations makes it important to understand those assumptions. The registry does not report a model rationale or diagnostics.

Why does the unit of analysis matter?

Randomization took place at eligible wound sites, and the primary outcome counts wounds. Participants may contribute more than one wound; the randomized-period description refers to at least 6 wounds or 3 wound pairs, and the study enrolled 6 participants. General statistical explanation: multiple wounds from one person may share characteristics and outcomes. If observations within a person are correlated, methods that assume every wound is independent can understate uncertainty. Analyses can account for such clustering, but the registry record does not report whether clustering was considered, how many wounds each participant contributed, or whether the analysis used wound-level or participant-level summaries.

The trial is listed as randomized and unmasked. Random allocation can help make treatment groups comparable on average, but it does not guarantee balance in a small study. Lack of masking can matter for outcomes that depend on judgment, such as wound assessment, unless assessment procedures address that possibility. The registry does not report masking of outcome assessors or additional safeguards for wound assessments.

How should the endpoint wording be read?

The named endpoint counts wounds with greater than 90% closure at 4 months. Its description also calls the comparison one of duration of wound closure. General statistical explanation: a time-to-event analysis uses event timing and can account for differing follow-up, whereas a threshold count at a fixed time records whether the event criterion was reached within that period. The posted primary values are counts, and the registry does not report event times, censoring details, or a time-to-event estimate. It is therefore more precise to interpret the displayed primary result as a count of wounds reaching the closure threshold within 4 months.

A confidence interval, when reported, describes a range of values compatible with the data and model at a stated confidence level. It communicates uncertainty around an estimate, but does not remove limitations in the design or analysis. No confidence interval or effect estimate is reported for this primary endpoint. This prevents a direct assessment of the precision of a group difference using an interval estimate.

What can planning illustrations tell us?

Any sample-size illustrations associated with these results are planning illustrations based on the observed effect, not the trial’s own design justification and not observed power. The stated planning assumptions are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. General statistical explanation: sample-size planning asks how many observations might be needed to detect a chosen effect under specified assumptions. Such illustrations depend on the assumed effect and model, and should not be mistaken for evidence that the completed study had a particular probability of finding a result. The trial’s own sample-size justification is not reported in the registry record.

General statistical explanation: over-dispersion arises when count variability exceeds what a proposed count model expects. If present, it can make standard errors too small unless the analysis accounts for the extra variability. The primary registry result uses a t-test and does not report a count-model analysis, an over-dispersion assessment, or diagnostic results. This concept is relevant to count outcomes in general, but the registry does not establish that over-dispersion occurred in this study.

The registry lists 6 outcome measures, 5 posted secondary outcomes, and 9 analyses. These totals indicate that the primary endpoint is not the only measured or analyzed outcome. General statistical explanation: examining multiple outcomes can increase the chance of at least one apparently notable result unless the analysis plan addresses multiplicity. The registry record does not report a multiplicity adjustment or a prespecified hierarchy for interpreting secondary outcomes. Without those details, secondary findings should be regarded as exploratory rather than as independent confirmation of the primary result.

10. Analyses Reported by the Sponsor

The registry reports the sponsor’s primary comparison as a two-sided t-test with p = 0.21. It does not report a confidence interval or an estimated difference for this comparison. A simple unadjusted recalculation is not available for this count-other endpoint because the posted summary values are not estimable for a two-arm recalculation. There is therefore no recalculated p-value or interval to compare with the sponsor’s result.

The posted outcome counts remain informative descriptively: 0 of 3 matrix-treated wounds and 3 of 3 standard-of-care-treated wounds reached greater than 90% closure within 4 months. These counts do not supply the uncertainty estimate that an inferential comparison or confidence interval would provide. The p-value summarizes the sponsor’s reported test; it should not be converted into a claim of equivalence or into a measure of the magnitude of the difference.

The registry does not describe the exact t-test implementation, the handling of multiple wounds per participant, or whether the analysis followed a prespecified statistical analysis plan. No discrepancy is identified between a sponsor result and a recalculation. Since a recalculation is unavailable, the posted sponsor analysis is the only reported inferential comparison for the primary endpoint. The registry record does not provide enough analysis detail to independently assess the test’s assumptions.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 6 outcome measures and 5 posted secondary outcomes. These include adverse-event profile characterization; change from baseline in wound pain and itch scores; and the number of wounds reaching greater than 50% or greater than 70% healing from baseline by investigator assessment. The primary endpoint instead uses a threshold of greater than 90% closure at 4 months. The registry also lists 9 analyses. The existence of several outcomes and analyses makes it important to distinguish the primary result from secondary or exploratory findings.

General statistical explanation: testing multiple outcomes can raise the chance of obtaining at least one apparently unusual result by chance. Prespecified priorities, hierarchical testing, or multiplicity adjustments are approaches that can help control interpretation, depending on the study’s aims. The registry record does not report a multiplicity adjustment, a testing hierarchy, or a complete statistical analysis plan. It is therefore not possible to determine from the record how the family of outcomes was handled. Secondary results should not be treated as independent confirmation of the primary endpoint without further information.

The primary endpoint population is described as participants with month 4 data. The registry does not report the number of participants with month 4 data, the number of missing wound assessments, reasons for missing data, or how missing outcomes were handled. It also does not report whether the primary analysis followed intention-to-treat, per-protocol, or another analysis-population definition. The posted results list 3 wounds in each randomized group, but that alone does not explain completeness at the participant level or how the wound counts correspond to participants.

General statistical explanation: excluding observations without follow-up can produce bias if the likelihood of missingness is related to treatment or outcome. Missing-data methods and sensitivity analyses can help assess the impact, but their suitability depends on the reason and pattern of missingness. Such methods and analyses are not reported in the registry record. The absence of these details limits assessment of whether the primary comparison represents all randomized wounds or only those with observed month 4 data.

The registry describes an optional open-label extension with no control or randomization. Results from that phase would answer a different question from the randomized comparison and should not be combined with it as if the treatment contrast were preserved. The record does not report a separate statistical plan for the extension.

12. 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.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: skin infection (16.7%), mammary gland carcinoma (16.7%).

For the randomized-period wound-treatment groups, the registry lists 6 participants at risk in each group. Serious adverse events affected 0 in the matrix-treated wound group and 0 in the standard-of-care-treated wound group. Other adverse events affected 3 of 6 in each group. The record lists no deaths in these groups.

Systemic adverse events are reported separately. In the randomized period, 6 participants were at risk; serious adverse events affected 1, other adverse events affected 5, and no deaths were listed. In the open-label period, 1 participant was at risk; no serious adverse events were listed, 1 participant had an other adverse event, and no deaths were listed. The open-label numbers describe a very small recorded group and are not a randomized comparison.

The serious-event terms listed include Skin infection at 16.7% and Mammary Gland Carcinoma at 16.7%. These are registry-listed event terms and percentages. The record does not establish that the study treatment caused either event, and the percentages alone do not describe timing, clinical course, or relatedness. Safety counts should be interpreted as reported events among the listed groups, not as proof of causation or as a comparison with statistical certainty.

Wound-treatment adverse-event groups and systemic adverse-event groups are separate entries. Their counts should not be added together because the registry does not explain whether participants or events overlap across entries. The safety summaries also do not replace the study’s primary wound-closure outcome.

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

The primary result is a small set of wound counts at a defined follow-up point: 0 of 3 matrix-treated wounds and 3 of 3 standard-of-care-treated wounds reached greater than 90% closure within 4 months. The sponsor-reported two-sided t-test p-value is 0.21. Taken together, the counts describe what was recorded in this pilot comparison; they do not establish a precise or generalizable treatment effect.

The result does not show that the treatments are equivalent. A p-value of 0.21 is not a test of equivalence, and no equivalence margin is reported. Nor does the result prove that one treatment is better. The observed counts point in one descriptive direction for this endpoint, but the very small number of wounds and the lack of a reported confidence interval leave the precision of the comparison unclear.

The primary outcome counts wounds crossing a closure threshold. It does not report average wound closure, the time taken to reach closure, or how long closure was maintained. Although the registry’s description refers to duration of wound closure, no event-time result is posted. It is therefore important not to extend the count result to claims about closure duration.

The study addresses a particular setting: RDEB wounds assessed in a randomized pilot comparison, with an optional open-label extension. The record does not establish that findings apply to other populations, wound types, treatment settings, or follow-up periods. It also does not provide the participant-level distribution of wound outcomes or details about handling dependence among wounds from the same participant.

The safety summaries record adverse events in randomized-period wound groups and systemic groups, including serious-event counts and listed event terms. They do not, on their own, establish that an event was caused by treatment. The study’s pilot size also means that these figures should be read as descriptive safety observations rather than as a definitive estimate of event risk.

Overall, the registry supports a narrow reading: it records different wound counts for the two randomized groups at the stated threshold and follow-up, alongside a reported p-value of 0.21. It does not provide the precision, analysis detail, or broader comparative evidence needed for stronger conclusions.

14. Why This Trial Matters Statistically

This study illustrates a recurring challenge in clinical biostatistics: the randomized units and outcome units may not be participants. Wounds were randomized, and the primary endpoint counts wounds, while the trial enrolled participants. When one participant can contribute multiple wounds, those wound outcomes may be correlated. The statistical analysis needs to reflect the assignment and dependence structure for its uncertainty estimates to be trustworthy. The registry does not report whether this was addressed.

It also highlights how endpoint wording affects interpretation. The primary description refers to duration of closure, but the named outcome and posted results are counts of wounds reaching greater than 90% closure within 4 months. These are different kinds of information. A fixed-time count does not reveal event timing or durability, so careful reading of the operational endpoint matters.

The posted counts are easy to understand, but the p-value alone offers limited information about precision. No confidence interval or estimated difference is reported. With 3 wounds listed in each group, descriptive observations should not be mistaken for a stable estimate that applies beyond this pilot. A small study can be useful for assessing feasibility and informing later research, but the registry does not report the protocol’s sample-size justification or a plan for a subsequent study.

Finally, the record includes multiple secondary outcomes and analyses, alongside an optional open-label extension. These features make clear distinctions among the primary randomized comparison, secondary outcomes, and uncontrolled extension especially important. The record does not report a multiplicity plan or detailed missing-data methods. Those omissions limit how confidently secondary results, if considered, can be interpreted alongside the primary result.

15. 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 comparison contains 3 wounds in each randomized group, within a study enrolling 6 participants. These small counts limit the amount of information available for estimating a treatment difference. The registry does not report a confidence interval, leaving the precision of an estimated contrast unclear.

The outcome is a wound count, and wounds may be contributed by the same participant. The record does not report how many wounds each participant contributed or whether the statistical analysis accounted for possible within-participant correlation. This leaves uncertainty about whether the reported t-test reflects the wound-level assignment and data structure.

The registry identifies participants with month 4 data as the primary endpoint population, but does not report the number with those data, missing wound assessments, reasons for missingness, or methods for handling missing outcomes. Analysis-population definitions are also not reported. These details are important for understanding which randomized observations the result represents.

The endpoint description refers to duration of closure, whereas the named outcome and posted values are counts of wounds reaching greater than 90% closure within 4 months. No event times or duration summaries are reported. The result therefore cannot describe how quickly wounds reached the threshold or how long closure persisted.

The study was unmasked, and the registry does not report whether outcome assessors were masked or what safeguards were used for investigator-assessed outcomes. It also does not report the detailed randomization method, allocation concealment, statistical analysis plan, multiplicity approach, or the study’s own sample-size justification. The optional open-label extension has no control or randomization, so it cannot provide the same controlled comparison as the randomized phase.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Pilot Study to Evaluate a Temporary Skin Substitute (Spincare® Matrix) for Wound Healing in RDEB Patients — NCT05944250.
• Registry record last updated 2025-09-15; status last verified 2025-08.
• Results first posted 2025-09-15.
• 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.

19. Record Summary

NCT05944250 is a completed, randomized, unmasked pilot study sponsored by Stanford University. It enrolled 6 participants with recessive dystrophic epidermolysis bullosa. The intervention was Spincare matrix, compared with standard-of-care wound dressings during the randomized wound-level phase. The study also described an optional open-label extension without control or randomization.

The primary endpoint was the number of wounds with greater than 90% closure at 4 months. The registry lists 0 of 3 matrix-treated wounds and 3 of 3 standard-of-care-treated wounds meeting that endpoint, with a two-sided t-test p-value of 0.21. No confidence interval or effect estimate is reported. The primary population is described as participants with month 4 data, but the number contributing those data and missing-data details are not reported.

Safety summaries list serious adverse events separately for wound-treatment and systemic groups, with no deaths reported. The small study size, wound-level outcome, limited inferential detail, and unreported handling of missing data and within-participant correlation constrain interpretation.