TWB-103 for Adult Patients With Split-Thickness Skin Graft Donor Site Wounds: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for TWB-103 for Adult Patients With Split-Thickness Skin Graft Donor Site Wounds (NCT02737748), a randomized phase 1, phase 2 study. The primary outcome is Number of Participants With Treatment-related AEs and SAEs (Including Infections and Bleeding).

2. Clinical Question

The trial therefore has related but distinct questions: whether treatment-related safety events were observed in Phase I, and whether healing time differed between treatment groups across Phase I and Phase II. The primary endpoint listed in the registry record is the number of participants with treatment-related adverse events and serious adverse events; it is not a reported comparison of healing time. The posted adverse-event counts describe participants with events in each group, but the record does not establish that these counts are the Phase I primary-endpoint result or that every event was treatment-related. The clinical question is consequently broader than the result information available: the registry record describes the planned objectives and some safety counts, but does not report a primary endpoint estimate or the central healing-time comparison.

3. Trial Design

This was a randomized, triple-masked, parallel-group Phase I/II study of TWB-103 and placebo in adults with split-thickness skin graft donor site wounds. The registry record lists enrollment of 48 and a completed status. The sponsor was Transwell Biotech Co., Ltd. The study began on 2017-07-06, and primary completion was recorded as 2021-05-07.

The two arms were described as receiving TWB-103 or placebo on matching schedules: 2 to 3 applications until 100% re-epithelialization or up to 10 days, around once every 3 days. The adverse-event group labels specify TWB-103 add-on Tegaderm and Placebo+Tegaderm. The registry record does not describe the precise roles of the masked parties or the method used to generate or conceal the random allocation.

The Phase I safety objective focused on treatment-related adverse events and serious adverse events, including infections and bleeding, from Day 0 to Day 28. The registry describes the primary safety observation as involving 7 patients in Phase I, while its population description says Phase I was planned to recruit 3 evaluable subjects in each group. These descriptions are not reconciled in the registry record. The efficacy objective for Phase I and Phase II was healing time from wound creation to 100% re-epithelialization. Other registered outcomes included wound closure and healing percentage at specified visits, pain change, adverse events and serious adverse events, and changes in physical examination and vital signs. The registry record does not report participant flow or the analysis population for these outcomes.

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: 48 subjects were screened in this study; 8 subjects were screen failures, resulting in 40 randomized subjects.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Phase I was planned to recruit 3 evaluable subjects each in TWB-103 and Placebo groups. Evaluable subjects in Phase I were (1) he/she who received at least one dose and had follow-up evaluation at least 14 days after the first dose or (2) he/she who received at least one dose and had early withdrawn due to safety reasons before Day 28.

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: \[Not Specified\]

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Treatment-related AEs and SAEs (Including Infections and Bleeding), measured over Day 0~Day 28.

The primary endpoint listed in the registry record is the number of participants with treatment-related adverse events and serious adverse events, including infections and bleeding. It is a count of participants who experienced an event, rather than a count of every event occurrence. The stated observation period is Day 0 to Day 28, and the description identifies the Phase I safety assessment.

Counting participants with an event is a way to describe how many people experienced at least one event during the specified period. Serious events and other adverse events have different clinical and regulatory meanings, so they should not be treated as interchangeable categories. The registry record does not provide a detailed definition of treatment-relatedness or explain the adjudication process for classifying an event as serious or related to treatment.

The endpoint is used to characterize safety, not to measure wound healing. Separately, the study's stated efficacy objective was healing time from donor site wound creation to 100% re-epithelialization. A time-to-healing outcome addresses how long healing takes; a participant count for adverse events answers a different question. The registry record does not report a numerical result for the primary safety endpoint or for the healing-time objective. The adverse-event counts posted by group should therefore be read as safety information, not as a substitute for either missing endpoint result.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as randomized, triple-masked, and parallel-group. In general, random assignment aims to make treatment groups comparable on average, while masking is intended to reduce the influence of expectations on care, assessment, or reporting. The registry record does not describe the randomization procedure, allocation concealment, or which people were masked. Those details are therefore not reported in the registry record, and the design labels alone cannot establish how these safeguards were implemented.

What does a participant count represent?

The listed endpoint is a count of participants with treatment-related adverse events and serious adverse events. A participant count indicates whether people experienced an event category during a stated period; it is not necessarily the total number of event episodes. A person could have more than one event, but the registry record does not say how repeat events were handled. The adverse-event results distinguish serious events from other events and list affected participants, participants at risk, and deaths for each group. The seriousness and treatment-relatedness classifications are not fully explained in the registry record.

How should a group comparison be assessed?

In general, a comparative analysis estimates how outcomes differ between groups and quantifies uncertainty around that estimate. For counts or binary outcomes, analysis choices can depend on the endpoint definition, the number of observed events, the analysis population, and the design. A confidence interval communicates precision; a hypothesis test addresses compatibility with a specified null model. The registry record does not report a comparative estimate, confidence interval, p-value, or the statistical procedure used for the primary safety endpoint. No inferential conclusion can be reconstructed from the posted counts without making assumptions about these missing details.

What is different about healing time?

Healing time is a time-to-event outcome: the event is reaching the defined healing state, here 100% re-epithelialization. In general, time-to-event methods can account for the timing of an event and for participants whose event time is not observed during follow-up. The study also registered a secondary healing measure requiring confirmation at least 10 days apart, assessed by the first additional evaluator. The record does not report the analysis method, censoring rules, assessment schedule for the primary healing-time objective, or results. Those elements are important for understanding how an observed healing time would be defined and compared.

What do the planning assumptions mean?

The registry record describes planning illustrations based on an observed effect, using a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It states that the effect to detect is a stated fraction of the observed effect. For time-to-event illustrations, the stated quantity is the total number of events; for other illustrations, it is participants per arm. These are planning assumptions, not observed trial results and not the trial's own design justification. The registry record does not report the trial's sample-size justification, the specific effect fractions used in the illustrations, or the values of any sample-size calculations in the registry record. Such planning calculations should not be described as observed power.

Why can over-dispersion matter?

In general, over-dispersion occurs when observed variability is greater than a statistical model assumes. If a model ignores that extra variability, its uncertainty estimates may be too small and its confidence intervals too narrow. This issue can matter for some count outcomes, especially when event counts vary more widely than a simple model expects. It does not establish that over-dispersion occurred in this trial. The registry record does not report a count model, a dispersion assessment, or an adjustment for over-dispersion.

The record lists 29 outcome measures and 3 analyses, but does not provide enough detail to identify the analysis set, model specification, covariate adjustment, missing-data approach, or handling of repeated assessments. The endpoint descriptions and group counts can be read descriptively; a fuller statistical interpretation requires analysis details and outcome results that are not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The study registered multiple outcomes, including the primary safety endpoint, the healing-time efficacy objective, wound closure and healing percentage at several visits, pain change, additional safety outcomes, and physical examination and vital-sign changes. When many outcomes or time points are assessed, the chance of at least one apparently unusual result can increase. In general, multiplicity procedures can control the interpretation of a family of tests, but the appropriate approach depends on the prespecified testing strategy. The registry record does not report a multiplicity adjustment, a hierarchy for testing outcomes, or which results were designated for confirmatory interpretation.

Missing-data handling is also not reported in the registry record. The Phase I population description defines evaluable subjects using receipt of at least one dose and follow-up evaluation at least 14 days after the first dose, or early withdrawal after receiving at least one dose. It does not explain how participants with incomplete outcome assessments were treated in analyses, or whether other analysis populations were used. The endpoint description's reference to 7 patients and the planned recruitment of 3 evaluable subjects per group are not reconciled.

The record lists enrollment of 48, while 20 participants at risk are listed for each adverse-event group. Participant flow, reasons for exclusion, and the relationship between those figures are not reported in the registry record. The record also does not describe imputation, sensitivity analyses, or how missing healing assessments would affect time-to-event analyses. Without these details, it is not possible to assess whether missingness or selective emphasis among multiple outcomes could affect the interpretation of 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.

Most frequent non-serious adverse event terms

The adverse-event records list 20 participants at risk in each group. Serious adverse events are listed for 0 participants in the TWB-103 add-on Tegaderm group and 0 participants in the Placebo+Tegaderm group. Deaths are listed as 0 in both groups. For other adverse events, the affected-participant counts are 7 for TWB-103 and 10 for placebo. These are counts, not calculated rates or treatment effects.

The distinction between serious and other adverse events matters: the zero serious-event counts do not mean that no adverse events of any kind were recorded. The record lists other affected participants in both groups. It also does not say whether those other events were treatment-related, whether they occurred during the Phase I primary-endpoint period, or how event severity and relatedness were determined. The primary safety objective refers specifically to treatment-related adverse events and serious adverse events, including infections and bleeding, whereas the group breakdown does not supply that classification detail.

Zero observed serious events does not establish zero risk. The registry record does not report a comparative safety analysis or uncertainty estimates for these counts. The figures therefore describe the posted safety records, but do not by themselves establish a causal difference between treatments or resolve the primary safety question.

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

The registry record establishes that the study was designed to compare TWB-103 with placebo in adults with split-thickness skin graft donor site wounds. It describes randomized, triple-masked, parallel-group allocation and an intervention schedule for both arms. It also identifies a Phase I safety objective and an efficacy objective focused on healing time to 100% re-epithelialization. These details explain what the trial set out to assess, but they are not themselves evidence of a treatment effect.

The posted adverse-event information describes zero serious events and zero deaths in each group, alongside other adverse-event counts of 7 and 10 participants. These figures are descriptive. They do not establish whether events were treatment-related, whether the counts align with the Phase I primary endpoint, or whether the groups differ beyond what might arise from chance. No comparative estimate or uncertainty interval is reported.

The record does not report a result for the primary safety endpoint or for the central healing-time objective. It also does not provide results for the listed secondary outcomes in the registry record. Consequently, the record cannot support a conclusion about whether TWB-103 changes healing time, wound closure, pain, or other outcomes relative to placebo.

In general, trial interpretation depends on outcome definitions, analysis populations, methods, estimates, and uncertainty—not only on the study design or raw counts. The registry record does not report several of these elements, including participant flow, missing-data handling, or the statistical plan. The posted information can be used to identify the questions studied and read the available safety counts, but it cannot substitute for unreported efficacy results or a full statistical analysis.

13. Why This Trial Matters Statistically

This trial raises a useful statistical distinction between safety and efficacy questions. Its listed primary endpoint counts participants with treatment-related adverse events and serious adverse events during a specified period, while its efficacy objective concerns time to 100% re-epithelialization. These outcomes have different definitions and require different interpretations. A safety count cannot answer a healing-time question, and a healing-time result would not by itself resolve the safety endpoint.

The record also illustrates why denominators and analysis populations matter. The enrollment figure is 48, the adverse-event groups each list 20 participants at risk, and the Phase I descriptions refer to 7 patients and planned recruitment of 3 evaluable subjects per group. These figures are not reconciled in the registry record. Without participant flow and clear analysis-set definitions, readers cannot determine how the posted counts map to the study's phases and planned endpoint population.

The trial has multiple registered outcomes, including assessments at different visits and several safety measures. In general, this makes prespecification and multiplicity handling important for distinguishing confirmatory findings from exploratory observations. The statistical plan and multiplicity approach are not reported in the registry record. Nor are comparative estimates and uncertainty measures reported for the safety counts.

Finally, the stated sample-size illustrations are planning exercises based on specified assumptions, not evidence about the precision of the observed trial results. Separating design labels, planning calculations, raw counts, and inferential results is essential: each answers a different statistical question. The record's gaps make that distinction particularly important when interpreting this study.

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.

Several limitations specific to this study are apparent from the registry record. The endpoint description says the Phase I safety observation involved 7 patients, while the population description says Phase I was planned to recruit 3 evaluable subjects in each group. The record does not explain the relationship between these descriptions. It also lists enrollment of 48, whereas each posted adverse-event group has 20 participants at risk; the participant flow and relationship between these figures are not reported.

The primary endpoint is described as treatment-related adverse events and serious adverse events, but the available group breakdown does not identify which events were treatment-related or whether it corresponds to the Phase I primary endpoint. The record does not report event definitions, adjudication procedures, or a comparative safety analysis. No results are reported for the healing-time objective, despite its role as the stated efficacy objective for Phase I and Phase II.

The registry record does not report the statistical analysis plan, analysis populations beyond the Phase I evaluable-subject description, missing-data procedures, multiplicity handling, or confidence intervals. It does not explain the roles covered by triple masking or the randomization and allocation-concealment procedures. The trial's sample-size justification is not reported in the registry record. These omissions limit assessment of precision, bias, and the consistency between planned and reported analyses.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: TWB-103 for Adult Patients With Split-Thickness Skin Graft Donor Site Wounds — NCT02737748.
• Registry record last updated 2023-07-28; status last verified 2023-06.
• Results first posted 2023-07-28.
• 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

NCT02737748 is a completed randomized, triple-masked, parallel-group Phase I/II study of TWB-103 versus placebo in adults with split-thickness skin graft donor site wounds. The registry record lists enrollment of 48 and identifies Transwell Biotech Co., Ltd. as sponsor. Both interventions were described as being administered 2 to 3 times until 100% re-epithelialization or up to 10 days, around once every 3 days.

The listed primary endpoint concerns participants with treatment-related adverse events and serious adverse events during Day 0 to Day 28 in Phase I. The study's efficacy objective concerns healing time to 100% re-epithelialization. Adverse-event records list 0 serious events and 0 deaths in each group, with other-event counts of 7 in the TWB-103 group and 10 in the placebo group. A primary endpoint result, healing-time result, comparative estimates, and key analysis details are not reported in the registry record.