Ovicidal Efficacy and Safety of Abametapir Lotion 0.74% Administered for the Treatment of Head Lice Infestation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ovicidal Efficacy and Safety of Abametapir Lotion 0.74% Administered for the Treatment of Head Lice Infestation (NCT02097485), a randomized phase 2 study. The primary outcome is Percentage of Hatched Eggs Pre Treatment Relative to Post Treatment.

2. Clinical Question

3. Trial Design

This was a Phase 2 randomized, double-blind, vehicle-controlled study with a parallel-group model. The registry record lists quadruple masking. Participants were assigned to abametapir lotion 0.74% w/w or vehicle lotion. Both were administered to the hair and scalp for 10 minutes. The stated purpose was to evaluate the ovicidal efficacy and safety of a single application of abametapir for head lice infestation.

The record reports an enrollment of 50. For the primary outcome, the reported group summaries each list 25 participants. The primary analysis population was not defined simply by randomization: subjects also had to receive any amount of study treatment and have at least 1 viable egg evaluable both before and after treatment. This eligibility requirement matters when interpreting the outcome because the primary summary concerns subjects meeting those criteria, rather than necessarily every randomized subject.

The study is listed as completed. Its recorded start was 2014-05 and its primary completion was 2014-09. These registry dates describe the study record; they do not provide additional detail about when each participant was treated or assessed.

The registry record describes a controlled comparison but does not report the method used to generate the random allocation sequence or the process used to conceal assignments. It also does not explain how masking was maintained or assessed. The quadruple-masking designation is recorded, but the roles included in that designation are not specified in the registry record. Further protocol details, including the planned sample-size justification, 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.

Overall Study

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS) included all randomized subjects who received any amount of study treatment and had at least 1 viable pre-treatment egg and 1 viable post-treatment egg evaluable for analysis.

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: All Randomized Population included subjects who were randomized into the study.

6. Primary Endpoint

The registry lists the primary outcome as Percentage of Hatched Eggs Pre Treatment Relative to Post Treatment, measured over 14 days.

The primary endpoint concerns egg hatching. For each treatment group, the reported measure is the percentage of eggs that hatched after treatment relative to the pre-treatment hatching percentage. The registry description defines the change as post-treatment hatching percentage minus pre-treatment hatching percentage. Eggs were incubated for 14 days before the post-treatment assessment.

This outcome was chosen to address the study’s stated ovicidal question: whether egg hatching was reduced after application. In general, an endpoint tied to egg hatching can provide a direct measure of the outcome of interest when evaluating an intervention intended to affect eggs. It is distinct from a measure of live lice or symptoms, neither of which is reported as the primary endpoint in this record.

The reported means are -92.9 for abametapir and -42.3 for vehicle. Because the endpoint is a post-minus-pre change, negative values indicate lower post-treatment hatching percentages than pre-treatment percentages on the reported scale. The confidence intervals describe uncertainty around each group mean. The registry record does not provide a direct estimate of the difference between the groups, so the two means should not be treated as a reported between-group effect.

The analysis population required viable eggs evaluable both before and after treatment. This makes the endpoint dependent on having those measurements available. The registry record does not report how many randomized subjects were excluded from the Full Analysis Set or why any pre-treatment or post-treatment egg measurements might not have been evaluable.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary outcome is continuous: it is expressed as a percentage-scale change in egg hatching. The registry record identifies the reported statistic as a mean and gives a 95% confidence interval for each group. A mean summarizes the average observed change in the analysis group. It does not show how individual participants’ or egg-level measurements varied around that average; a standard deviation or other measure of individual-level spread is not reported.

What does the confidence interval describe?

In general, a confidence interval expresses uncertainty about an estimated quantity under a statistical method and its assumptions. The intervals in this record accompany the group means, so they describe uncertainty around each arm’s mean change. They do not directly quantify uncertainty about the difference between arms. A comparison requires an estimate of that difference and its uncertainty, neither of which is reported in the registry record.

The interval endpoints are -99.4 and -86.5 for abametapir, and -54.4 and -30.2 for vehicle. The corresponding means are -92.9 and -42.3. As the endpoint is post-treatment minus pre-treatment, a negative value represents a decrease on the reported scale. The confidence intervals also lie below zero for both group means. This observation concerns each group separately; it is not a test of whether the groups differ.

Why is the direct comparison important?

In a randomized comparison, the primary treatment question concerns the contrast between assigned groups, not just whether either group changed from its pre-treatment value. A direct estimate would quantify the difference in mean changes, with an uncertainty interval or test result to show its precision. The registry record does not report those comparison statistics. The available summaries can be described side by side, but a new contrast should not be calculated from them for this account.

The record indicates that values were missing or not estimable for a two-arm comparison of this continuous endpoint. As a result, no recalculated comparison is presented. There is no reported discrepancy between the posted results and a recalculated comparison, because such a comparison is not available in the record.

What does the analysis population mean?

The Full Analysis Set included randomized subjects who received any amount of study treatment and had at least 1 viable pre-treatment egg and 1 viable post-treatment egg evaluable for analysis. In general, such eligibility rules define which observations contribute to the endpoint analysis. They also mean the group summaries do not automatically represent every randomized subject. The registry record does not report a detailed flow from randomization to inclusion in this analysis population, or describe the handling of subjects who lacked evaluable eggs.

What do the planning calculations represent?

In general, sample-size calculations illustrate how many participants might be needed under specified assumptions to detect an effect with a chosen statistical power. The planning illustration described in the record uses the observed effect as its reference, assumes two-sided significance level 0.05, equal allocation, and a normal approximation, and considers the effect to detect as a stated fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence that the trial was originally designed using those assumptions. The trial’s own sample-size justification is not reported in the registry record.

The record states that non-time-to-event planning results are expressed as participants per arm. No numerical planning results are included in the registry record for this explanation, so no planning sample size is stated. General statistical interpretation also depends on assumptions about the distribution and variability of the outcome. The registry record does not report details of the confidence-interval method, model specification, or any assessment of those assumptions.

How should the reported precision be read?

The confidence intervals give a sense of precision for the arm-specific means, but precision of a mean is not the same as precision of a treatment contrast. In general, a comparison’s uncertainty depends on the variability and amount of information in both arms and on the analysis method. Because the record does not provide a direct comparison estimate, readers cannot use these arm-specific intervals alone as a substitute for its confidence interval or test.

The endpoint also depends on paired pre-treatment and post-treatment egg information. In general, repeated measurements can help describe change within a participant or sample, but the registry record does not state how egg measurements were aggregated, whether the analysis accounted for clustering of eggs within participants, or what distributional methods were used. Those methodological details are not reported in the registry record. The posted group means and intervals should therefore be interpreted according to the endpoint definition and population description available, without assuming an unreported model or analysis plan.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 1 outcome measure and no posted secondary outcome results. It also does not provide a multiplicity strategy, such as a prespecified hierarchy or adjustment for testing multiple endpoints. Because no primary between-group test result is posted, there is no reported p-value from which to assess any multiplicity adjustment. The record does not establish whether additional analyses were planned but not reported.

The primary analysis population required subjects to be randomized, to receive any amount of treatment, and to have at least 1 viable pre-treatment and 1 viable post-treatment egg evaluable. This definition identifies the observations used for the primary outcome, but it does not explain how missing or unevaluable measurements were handled. The registry record does not report imputation, sensitivity analyses, reasons for missing data, or a comparison of included and excluded subjects.

The group summaries list 25 participants in each arm. The record does not include a participant-flow description connecting those analysis counts to the enrollment figure, or an account of any post-randomization exclusions. It is therefore not possible to assess from the registry record whether missing measurements could have affected the observed group means.

The number of analysis entries posted is 0. This is a statement about what appears in the registry record, not proof that no analysis was conducted. Details of the statistical analysis plan, including any prespecified handling of missing outcomes, are not reported in the registry record.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety summary lists 25 participants at risk for serious adverse events in each group. Serious adverse events are reported for 0 in the abametapir group and 0 in the vehicle group. Deaths are also reported as 0 in each group. These are counts in the registry record; they do not show that the possibility of a serious event or death was ruled out.

Other adverse events are reported for 4 participants in the abametapir group and 2 in the vehicle group. The record does not provide further terms for these events in the posted summary, and no serious adverse-event terms are listed. It also does not report a formal comparison or uncertainty estimate for the safety counts. The counts should therefore be read descriptively rather than as evidence of a statistically established difference between groups.

In general, safety findings depend on the events collected, the observation period, and how events are defined and attributed. The registry record does not provide enough detail to evaluate those features or to draw conclusions beyond the reported counts.

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

The posted primary results show negative mean changes in egg hatching in both groups after treatment, with a more negative reported mean in the abametapir group than in the vehicle group. The endpoint is the post-treatment hatching percentage minus the pre-treatment percentage following 14 days of incubation. Thus, the signs of the means indicate a decrease on that measure. The record also reports 95% confidence intervals for each group mean.

These data do not, by themselves, provide a complete statistical answer to the comparative question. The registry record does not report a direct between-group estimate, its confidence interval, or a p-value. It is therefore not possible to state from the posted results how precisely the difference between groups was estimated or whether a prespecified statistical criterion was met. The arm means are not a substitute for that missing comparison.

The outcome is specific to egg hatching. It should not be interpreted as a measure of every aspect of head lice infestation or as evidence about outcomes that were not reported as primary. The record does not post secondary outcome results. It also does not report how the observed egg-hatching change relates to other clinical outcomes.

The analysis applies to the Full Analysis Set, which required treatment receipt and evaluable viable eggs before and after treatment. The record does not state how many randomized subjects were not included in that analysis or how unevaluable measurements were handled. This limits assessment of how representative the reported summaries are of all randomized subjects.

The safety record reports no serious adverse events or deaths in either arm, alongside other adverse-event counts of 4 and 2. These counts are limited descriptions of the recorded safety outcomes. They do not establish that an event cannot occur, and the registry record does not supply a comparative safety analysis.

In short, the registry record presents group-level egg-hatching summaries and limited safety counts. It does not provide the comparative inferential results or methodological detail needed for a fuller assessment of the precision and robustness of the findings. No conclusion beyond those posted data is warranted from these summaries alone.

13. Why This Trial Matters Statistically

This study illustrates a useful statistical distinction between change within groups and the contrast between randomized groups. The primary endpoint is defined as post-treatment minus pre-treatment hatching percentage, and the record reports a mean and confidence interval for each arm. Those summaries describe the direction and precision of each group’s change. The treatment comparison, however, requires a direct estimate of how the groups differ. That estimate and its uncertainty are not reported in the registry record.

The distinction matters because a change observed in an intervention group is not, on its own, an estimate of the intervention’s comparative effect. The vehicle group also had a negative mean change. A reader needs the direct contrast to understand the estimated difference between groups and how uncertain it is. Comparing two arm-specific means informally cannot replace a reported analysis of that contrast.

The endpoint also highlights the importance of defining the analysis population. The Full Analysis Set required viable eggs evaluable before and after treatment, in addition to randomization and treatment receipt. This definition is relevant to interpretation because the outcome depends on paired pre- and post-treatment information. Without a participant-flow account and missing-data methods, readers cannot assess how the analysis population relates to all randomized subjects.

Finally, the record shows why registry summaries and statistical methods need to be read together. Group means, confidence intervals, and adverse-event counts are informative descriptions, but the record does not report a primary comparison test, a detailed analysis plan, or a multiplicity strategy. Recognizing what is and is not reported helps distinguish descriptive evidence from a fully documented comparative inference.

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 trial-specific limitations follow from the registry record. The reported primary endpoint summaries are arm-specific; a direct comparison estimate, confidence interval, and p-value are not reported. The group means therefore cannot quantify the precision of the treatment contrast. The registry record also indicates that a two-arm comparison value was missing or not estimable.

The analysis population required subjects to have viable eggs evaluable both before and after treatment. The record does not provide a flow of subjects into that population, explain exclusions, or report the handling of missing and unevaluable measurements. As a result, the possible influence of incomplete outcome data cannot be assessed from the registry record.

Statistical-method details are sparse. The record does not report the method used to calculate the confidence intervals, the model or other analysis procedure, or whether assumptions were assessed. It does not provide a multiplicity plan or a statistical analysis plan. The original sample-size justification is not reported; planning illustrations based on observed effects should not be treated as the trial’s original design rationale.

The safety summary gives counts but no event-level descriptions for other adverse events and no formal comparative analysis. Serious adverse-event terms are not listed. The record also does not specify the roles covered by quadruple masking or explain allocation concealment. These unreported details limit assessment of the trial’s conduct and the robustness of its interpretation.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Ovicidal Efficacy and Safety of Abametapir Lotion 0.74% Administered for the Treatment of Head Lice Infestation — NCT02097485.
• Registry record last updated 2021-05-11; status last verified 2021-04.
• Results first posted 2021-05-11.
• 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

The registry record describes a completed Phase 2 randomized, double-blind, vehicle-controlled, parallel-group study of abametapir lotion 0.74% w/w for head lice infestation. The treatment and vehicle were applied to the hair and scalp for 10 minutes. The stated purpose was to evaluate ovicidal efficacy and safety after a single application.

The primary endpoint was the change in egg-hatching percentage, defined as post-treatment minus pre-treatment after 14 days of incubation. The reported group means were -92.9 for abametapir and -42.3 for vehicle, with respective 95% confidence intervals of -99.4 to -86.5 and -54.4 to -30.2. A direct two-arm comparison is not reported.

The Full Analysis Set required treatment receipt and at least 1 viable egg evaluable before and after treatment. The safety summary reports 0 serious adverse events and 0 deaths in each arm; other adverse events are reported for 4 and 2 participants, respectively. Details of missing-data handling, the statistical analysis plan, and the original sample-size justification are not reported in the registry record.