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 An Evaluation of the Safety and Pharmacokinetics of Tavaborole Topical Solution for the Treatment of Fungal Disease of the Toenail in Children and Adolescents (NCT03405818), a na phase 4 study. The primary outcome is Number of Participants With Local Tolerability Reactions by Severity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03405818 |
| Phase | Phase 4 |
| Condition | Onychomycosis, Tinea Unguium |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 55 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
Children and adolescents with toenail onychomycosis were enrolled. The official title describes pediatric subjects ages 6 to 16 years and 11 months. Eligibility included laboratory evidence of a fungal organism in the toenail. The registry lists an enrollment of 55; the primary outcome population is defined as participants who received at least 1 confirmed dose and had at least 1 post-baseline safety assessment.
Intervention
Participants applied tavaborole 5% topical solution once daily to all affected toenails for a 48-week treatment period. The study was open-label, so masking was none. A subgroup applied treatment to all 10 toenails and a small area of surrounding skin during the first 28 days, with blood samples analyzed to evaluate pharmacokinetics.
Comparator
There was no concurrent control group. The study is listed as a single-group study, and allocation is listed as not applicable. Consequently, the registry record does not support a like-for-like comparison between tavaborole and another treatment or a control condition.
Primary question
The primary outcome asks how many participants experienced local tolerability reactions, classified by severity, from baseline up to Week 52. Reactions included burning or stinging, induration or edema, oozing and crusting, pruritus, erythema, and scaling. The record also lists pharmacokinetic and clinical efficacy outcomes, but does not report their results in the registry record.
3. Trial Design
This was a completed Phase 4, open-label, single-group study sponsored by Pfizer. It evaluated tavaborole 5% topical solution in pediatric participants with onychomycosis of the toenail. The registry lists enrollment of 55. The study started on 2015-10-22, and primary completion was 2017-07-27.
After eligibility was confirmed, including laboratory evidence of a fungal organism in the toenail, participants applied the solution once daily to all affected toenails during a 48-week treatment period. Clinical assessments of infection extent and safety assessments occurred periodically during treatment and again at 52 weeks, described as 4 weeks after treatment stopped.
A subgroup used the solution on all 10 toenails and a small area of surrounding skin during the first 28 days. Blood samples from these participants were analyzed for tavaborole pharmacokinetics. The registry lists outcomes including maximum observed plasma concentration, time to maximum concentration, area under the plasma concentration-time curve, elimination rate constant, and elimination half-life. Numerical results for these pharmacokinetic outcomes are not reported in the registry record.
There was no randomized allocation or masked treatment, and no concurrent comparator arm. The registry record therefore describes observations during treatment rather than a randomized estimate of the difference between tavaborole and another condition. Further detail about the protocol, including any additional design rationale, is not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Overall Study
| Stage | Kerydin |
|---|---|
| STARTED | 55 |
| COMPLETED | 47 |
| NOT COMPLETED | 8 |
Reasons for not completing this period:
| Reason | Kerydin |
|---|---|
| Withdrawal by Subject | 4 |
| Lost to Follow-up | 4 |
Analysis population for the primary outcome, as defined in the registry: Safety Population: all participants who received at least 1 confirmed dose of study drug and had at least 1 post-baseline safety assessment.
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: Safety population included all participants who received at least 1 confirmed dose of study drug and had at least 1 post-baseline safety assessment.
| Characteristic | Unit | Kerydin |
|---|---|---|
| Participants analysed | 54 | |
| Age, Continuous | years | 13.2 (SD 2.69) |
| Sex: Female, Male: Female | Participants | 17 |
| Sex: Female, Male: Male | Participants | 37 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 27 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 27 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 8 |
| Race (NIH/OMB): White | Participants | 46 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Local Tolerability Reactions by Severity, measured over Baseline up to Week 52.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with local tolerability reactions by severity from baseline up to Week 52. It concerns reactions at or around the treated area, rather than a measure of fungal clearance. The registry lists burning or stinging, induration or edema, oozing and crusting, pruritus, erythema, and scaling, with severity categories of none, mild, moderate, and severe. The outcome description gives a symptom-specific grading scale for each reaction.
A participant count is a straightforward way to describe how many people experienced a reaction in the safety population. Severity categories add context that a single yes-or-no count would not convey. In general, local tolerability measures can help characterize the kinds and intensity of reactions observed during topical treatment. They do not, by themselves, establish that a reaction was caused by treatment.
The registry defines the safety population as participants who received at least 1 confirmed dose and had at least 1 post-baseline safety assessment. However, the actual primary endpoint counts and severity-specific results are not reported in the registry record. The record therefore identifies what was to be measured, but does not provide the numerical outcome needed to describe the observed local tolerability profile.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The design is important for interpreting the available findings. Because the study was open-label and single-group, observations can describe participants treated with tavaborole but cannot establish how those observations compare with an untreated group or another therapy. No randomized comparison is listed. Differences attributable to participant characteristics, the course of the condition, or other influences cannot be separated from treatment effects using this design alone.
The registry identifies a primary safety and tolerability outcome, but does not report the number of participants with local reactions or the counts by severity. It also lists clinical efficacy outcomes at Week 24 and Week 52, including almost complete cure and clinical efficacy of the target great toenail. Their numerical results are not reported in the registry record. The record therefore does not permit a numerical interpretation of either the primary endpoint or those clinical outcomes.
For adverse events, the record lists 1 participant with a serious adverse event among 54 at risk, 30 with other adverse events among 54 at risk, and 0 deaths. Appendicitis is listed as the top serious term at 1.9%. These are descriptive counts from the recorded safety group. They do not show, by themselves, whether an event was caused by tavaborole, and they do not replace the missing local tolerability endpoint results.
Precision cannot be assessed for the primary outcome because its numerical results and a confidence interval are not reported in the registry record. A confidence interval, in general, describes the range of values compatible with an estimate under the model used; it does not eliminate design limitations or establish causation. No inferential analysis results are listed in the registry record.
The registry lists 38 outcome measures, which indicates that the study recorded a broad set of outcomes. The presence of multiple outcomes does not establish that every result was reported or that any particular analysis was prespecified. Details about analysis selection and multiplicity handling are not reported in the registry record. Accordingly, the safest reading is descriptive: the record documents the study design and some safety-event summaries, while leaving the primary local tolerability results and several other outcome results unavailable.
9. Statistical Methods Explained
Statistical methods depend on the question being asked and the structure of the data. In this study, the primary endpoint is a count of participants experiencing local tolerability reactions, with reaction severity also classified. The design is single-group, so the principal descriptive information would concern the treated participants rather than a treatment-versus-control contrast. The registry record does not report the primary endpoint counts or a statistical analysis plan.
What does a participant count describe?
A count describes the number of people meeting an outcome definition. For this endpoint, the outcome definition concerns specified local reactions and their grades. Counts can be useful for safety description because they retain a direct connection to how many participants had an event. When interpreting any count, the population definition and the observation period matter: the registry specifies a safety population and a timeframe from baseline up to Week 52. The numerical results for this endpoint are not reported in the registry record, so its observed frequency and severity distribution cannot be described.
Why does the design limit comparisons?
A randomized comparison can help distinguish treatment-related differences from differences that would occur between groups for other reasons. Here, allocation is listed as not applicable, masking is none, and the model is single-group. There is no concurrent control arm against which to estimate a treatment difference. A before-and-after description, if reported, would still not by itself resolve influences such as the natural course of the condition or changes in assessment over time. No adjusted comparison or causal analysis is reported in the registry record.
How should uncertainty be considered?
In general, estimates based on participant counts have sampling uncertainty. A confidence interval communicates that uncertainty around an estimate under specified statistical assumptions. Its interpretation depends on the analysis method and the data used. No confidence interval for the primary local tolerability endpoint is reported in the registry record, so the precision of that endpoint cannot be evaluated from the posted results. Statistical significance is also not a substitute for effect size, precision, or assessment of study design.
In general, over-dispersion occurs when observed variability is greater than a statistical model expects. It can make a model that assumes less variability understate uncertainty. This is relevant to some count outcomes, especially when event counts vary more widely than a simple model allows. The registry record does not report a count model or indicate that over-dispersion was assessed for this trial; this general concept should not be mistaken for a description of the analysis used.
What do the planning assumptions mean?
The registry describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such calculations are planning illustrations, not observed power and not evidence that the study had a particular probability of detecting an effect. The described two-arm allocation does not match this study's single-group design. The registry record does not report the trial's own sample-size justification, so the illustration should not be treated as the rationale for the enrolled group.
What is not available?
There are no analysis results listed in the registry record. The specific statistical tests, model choices, covariate adjustments, confidence interval methods, and any interim analyses are not reported in the registry record. The handling of repeated observations over the treatment period is also not reported. These omissions mean that a reader cannot reproduce or fully assess the statistical approach to the endpoint from the registry record alone. General statistical explanations describe possible methods, not methods confirmed for this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 38 outcome measures, covering safety, pharmacokinetics, and clinical outcomes. When a study considers many outcomes, multiplicity can matter: in general, evaluating numerous hypotheses can increase the chance that at least one result appears noteworthy by chance. A prespecified hierarchy, adjustment method, or other strategy can help clarify how multiple results should be interpreted. Whether such a strategy was used is not reported in the registry record.
The registry record does not list analysis results. It also does not report how missing observations were handled, whether participants who stopped treatment remained in particular analyses, or whether any sensitivity analyses were performed. Those details matter because incomplete follow-up or unavailable measurements can affect the population represented by an estimate. No assumption about missingness or imputation can be made from the posted information.
The primary outcome population is defined as participants who received at least 1 confirmed dose and had at least 1 post-baseline safety assessment. That definition identifies who could contribute to the safety outcome, but the registry record does not report how many met it for the primary endpoint or provide the outcome counts. The adverse-event summaries use a group at risk of 54; that safety denominator should not be silently substituted for the primary endpoint population definition.
The registry record does not report the statistical analysis plan, interim analyses, or a specific multiplicity procedure. Consequently, the listed outcomes identify what was measured, but do not establish which analyses were confirmatory or how missing data and multiple outcomes were addressed.
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 |
|---|---|---|---|
| Kerydin | 1 | 54 | 1.9% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Kerydin | 0 of 54 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Kerydin | 30 of 54 |
Most frequent serious adverse event terms
| Event term | Organ system | Kerydin |
|---|---|---|
| Appendicitis | Infections and infestations | 1 of 54 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Kerydin |
|---|---|---|
| Nasopharyngitis | Infections and infestations | 7 of 54 |
| Contusion | Injury, poisoning and procedural complications | 5 of 54 |
| Sinusitis | Infections and infestations | 3 of 54 |
| Vomiting | Gastrointestinal disorders | 3 of 54 |
| Influenza | Infections and infestations | 2 of 54 |
| Concussion | Injury, poisoning and procedural complications | 2 of 54 |
| Oropharyngeal pain | Respiratory, thoracic and mediastinal disorders | 2 of 54 |
| Headache | Nervous system disorders | 2 of 54 |
| Acute sinusitis | Infections and infestations | 1 of 54 |
| Conjunctivitis | Infections and infestations | 1 of 54 |
Serious events with the highest arm-level rate: appendicitis (1.9%).
The adverse-event summary lists 54 participants at risk for serious adverse events and 54 at risk for other adverse events. It records 1 participant with a serious adverse event, 30 with other adverse events, and 0 deaths. Appendicitis is listed as the top serious term at 1.9%.
These figures are descriptive safety summaries. “Serious” and “other” are separate adverse-event categories in the registry summary; the figures do not provide a severity breakdown for the primary local tolerability endpoint. The record does not state whether participants with a serious event were also among those counted for other adverse events, so the counts should not be combined or treated as mutually exclusive.
The serious-event count does not establish that tavaborole caused the event. Nor does the absence of recorded deaths establish that no other safety concern occurred. The primary local tolerability results, including counts by reaction and grade, are not reported in the registry record, so the adverse-event summary cannot stand in for those results.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a pediatric, open-label, single-group study evaluated once-daily tavaborole 5% topical solution applied to affected toenails over a 48-week treatment period, with assessment again at 52 weeks. It describes a primary endpoint focused on local tolerability and lists pharmacokinetic and clinical outcomes. The record also includes a limited adverse-event summary.
What the record does not establish is the observed result for the primary endpoint. Counts of participants with local reactions and their severity are not reported in the registry record. Numerical results for the listed clinical efficacy and pharmacokinetic outcomes are also not reported. As a result, the posted record does not support a numerical conclusion about those outcomes.
The study has no concurrent control group and no masking. Observations in a single treated group cannot show what would have happened under a different treatment or no treatment. The design therefore does not estimate a randomized treatment effect. Even if outcome changes were available, a single-group design would require caution when attributing them to treatment.
The safety summary records 1 serious adverse event, 30 participants with other adverse events, and 0 deaths among the listed safety group, with appendicitis identified as the top serious term at 1.9%. These figures describe recorded events; they do not by themselves determine cause or establish a full benefit-risk profile.
In general, a registry entry is useful for understanding study design and the outcomes selected, but its interpretive value depends on whether results and analysis details are present. Here, the design is clear enough to identify the study as descriptive and uncontrolled, while missing endpoint results and analysis information constrain what can be concluded.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how design determines the questions that results can answer. An open-label, single-group study can document what was observed among treated participants, including safety events, but it cannot make a randomized comparison with a control condition. That distinction is central when interpreting any apparent change in infection or tolerability over time.
The primary endpoint is framed as participant counts by local reaction severity, which is a direct safety-oriented measure. Its interpretation depends on the stated safety population and follow-up period. However, the numerical endpoint results are not reported in the registry record. The design and measurement definitions can therefore be reviewed, while the observed distribution of reactions cannot.
The record also illustrates the difference between a broad set of measured outcomes and a complete statistical account. It lists 38 outcome measures, including pharmacokinetic and clinical outcomes, but does not report analysis results or how multiplicity and missing observations were handled. Those details matter for assessing uncertainty, selective emphasis, and reproducibility.
Finally, a planning illustration based on a two-arm setup should not be confused with the actual single-group design or with observed power. Planning calculations address hypothetical design choices; they do not supply missing results or establish that a particular effect was detected. The registry record's limitations make careful separation of design details, descriptive safety counts, and unreported outcomes especially important.
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 principal limitation for interpreting outcomes is that the registry record does not report the primary local tolerability counts or severity results. It also does not report numerical results for the listed clinical efficacy or pharmacokinetic outcomes. This prevents assessment of the magnitude and precision of those outcomes from the registry record.
The study had no concurrent comparator and was open-label. As a result, it cannot provide a randomized estimate of the difference between tavaborole and another treatment or control condition. The record does not describe masking, and none is listed. Participant or assessor knowledge of treatment may also be relevant to subjective assessments, although the record does not quantify any such influence.
The registry lists an enrollment of 55, while the adverse-event summary lists 54 at risk. These figures refer to different stated summaries and should not be treated as interchangeable denominators. The actual number contributing to the primary endpoint is not reported in the registry record. Missing-data handling, reasons for unavailable observations, and sensitivity analyses are not reported.
The record lists many outcome measures but does not report the analysis plan, multiplicity handling, or interim analyses. It therefore does not show which outcomes were designated for confirmatory interpretation or how uncertainty across outcomes was managed. The registry also does not report the trial's own sample-size justification. These limitations constrain statistical interpretation beyond the basic design and the adverse-event counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: An Evaluation of the Safety and Pharmacokinetics of Tavaborole Topical Solution for the Treatment of Fungal Disease of the Toenail in Children and Adolescents — NCT03405818.
- Registry record last updated 2018-04-17; status last verified 2018-03.
- Results first posted 2018-04-17.
- 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
This completed Phase 4 study evaluated tavaborole 5% topical solution in children and adolescents with toenail onychomycosis. It was open-label and single-group, with enrollment of 55. Participants applied the solution once daily to affected toenails for 48 weeks, with assessment at 52 weeks.
The primary outcome concerned participant counts for local tolerability reactions by severity. The record also lists pharmacokinetic and clinical outcomes. It does not report numerical results for the primary endpoint or those listed outcomes. The adverse-event summary records 1 serious adverse event, 30 participants with other adverse events, and 0 deaths among 54 at risk for each category. No concurrent comparator was used, limiting interpretation to descriptive observations rather than a randomized treatment comparison.