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 Safety and Tolerability of a Novel Malathion Formulation in Children Age 6-24 Months With Head Lice (NCT00752973), a non-randomized phase 2, phase 3 study. The primary outcome is Participants With a Change in Cholinesterase Level at 1 Hour (Day 0)..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00752973 |
| Phase | Phase 2, Phase 3 |
| Condition | Pediculosis |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sun Pharmaceutical Industries, Inc. |
| Results posted | Yes |
2. Clinical Question
Population
Children aged 6–24 months with pediculosis capitis, or head lice. The record states that the primary endpoint population included 10 subjects with an obtained blood sample. It also describes two subject-specific difficulties obtaining a post-treatment sample at Visit 1, Day 0.
Intervention
MALG treatment, described as a malathion gel formulation at 0.5%. The study assessed the formulation in infants and toddlers, with blood markers and clinical evaluations intended to address safety and tolerability.
Comparator
There was no separate comparator group. The registry describes a non-randomized, single-group study with one treatment arm. The primary endpoint compares post-treatment cholinesterase measurements with baseline measurements within the treated group.
Primary question
What was the mean percentage change in plasma and red blood cell (RBC) cholinesterase activity from baseline to 1 hour after treatment application, and how precisely was that change estimated? Cholinesterase measurements were also scheduled at 24 hours, but the named primary endpoint is the change at 1 hour. The numerical mean changes and confidence intervals are not reported in the registry record.
3. Trial Design
The registry describes a Phase II, multi-center, open-label safety and tolerance study of a malathion formulation in infants and toddlers with pediculosis capitis. It lists the study phases as Phase II and Phase III. Allocation was non-randomized, masking was none, and the model was single group. The listed intervention was MALG treatment, and the arm description identifies a treatment arm rather than a treatment-versus-control comparison.
The record reports an enrollment of 12. The study status is completed. The recorded start is 2008-09 and primary completion is 2011-12. Those registry entries describe the study record; they do not provide details about recruitment, follow-up completion, or the number included in each analysis.
The primary endpoint concerns the mean percentage change in plasma and RBC cholinesterase activity from baseline to 1 hour after application, on Day 0. The endpoint description says each patient was assessed at that time and reports that 10 subjects had an obtained blood sample. It identifies one subject for whom a post-treatment sample could not be obtained at Visit 1, Day 0, and another for whom a sample could not be obtained even after two attempts. Measurements were also scheduled at baseline and 24 hours after application, on Day 1.
The registry lists evaluation of local safety based on reported adverse events and observed scalp reactions as a secondary outcome. It reports seven outcome measures and no analysis records. The registry record does not report the protocol, further details of study conduct, or a comparator group. Because there was no separate control arm, the design describes changes and adverse events in the treated group; it does not provide a randomized comparison of treatment with another intervention or with no treatment.
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 | Malathion Gel 0.5% Treatment Arm |
|---|---|
| STARTED | 12 |
| COMPLETED | 12 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: 10 subjects with obtained blood sample. subject 01-003: Study coordinator was unable to obtain blood sample post treatment at Visit 1, Day 0. subject 01-004: At Visit 1 Day 0 (post treatment), Blood sample could not be obtained even after two attempts.
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.
| Characteristic | Unit | MALG Treatment Arm |
|---|---|---|
| Participants analysed | 12 | |
| Age, Continuous | months | 17.5 (SD 4.64) |
| Sex: Female, Male: Female | Participants | 10 |
| Sex: Female, Male: Male | Participants | 2 |
| 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 | 0 |
| Race (NIH/OMB): White | Participants | 9 |
| Race (NIH/OMB): More than one race | Participants | 1 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 2 |
6. Primary Endpoint
The registry lists the primary outcome as Participants With a Change in Cholinesterase Level at 1 Hour (Day 0)., measured over Change from Baseline to 1 hour.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | percentage change in cholinesterase |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the mean percentage change in cholinesterase activity from baseline to 1 hour after treatment application, reported separately for plasma and RBC cholinesterase. The registry describes the endpoint as a reduction and gives the calculation as (post-treatment value − baseline)/baseline × 100. Under that stated calculation, a value below baseline is represented as a negative percentage change.
Cholinesterase measurements are blood markers. The registry’s rationale is that the size and precision of observed changes could be considered in relation to established safety guidelines. It says that sufficiently narrow confidence intervals around the changes would show whether observed reductions fall within those guidelines. However, the guidelines themselves, a decision threshold, the observed mean changes, and the confidence intervals are not reported in the registry record. The rationale therefore does not establish what the measurements showed.
Measurements were scheduled at baseline, 1 hour (Day 0), and 24 hours (Day 1). The named primary endpoint is specifically the change from baseline to 1 hour; the later measurement is not the stated primary time point. The endpoint description reports 10 subjects with an obtained blood sample and identifies sample-collection difficulties for subject 01-003 and subject 01-004 at the post-treatment assessment on Day 0. Numerical endpoint results and details of how missing measurements were handled are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies the outcome of interest but does not give the numerical primary-endpoint results. In particular, it does not report the mean percentage change in plasma cholinesterase, the mean percentage change in RBC cholinesterase, or either confidence interval. Without those estimates, it is not possible to describe the direction or magnitude of the observed changes or the precision with which they were estimated. The endpoint description’s stated safety rationale is not itself evidence that a particular result met a guideline.
The record states that 10 subjects had an obtained blood sample for the primary endpoint. It separately describes a post-treatment sample that could not be obtained for subject 01-003 and another that could not be obtained for subject 01-004 despite two attempts. The registry does not explain whether all available measurements were used, whether subjects with incomplete samples were excluded from particular summaries, or how missing values were handled. Consequently, the reported endpoint population cannot be fully characterized beyond the stated sample information.
The analysis is within a single treatment group, comparing post-treatment measurements with baseline. It is not a randomized between-group estimate. Any change observed in this design would describe the measured change among participants with usable data; by itself, it would not separate treatment-associated change from other explanations such as natural variation or measurement variation. The registry record does not report an adjusted analysis or other method to address such explanations.
The record lists seven outcome measures but no analysis records. That means the registry does not furnish analysis details with which to assess the primary estimate, such as the method used to calculate uncertainty or the treatment of incomplete measurements. It does not establish that no analyses were conducted; their results and methods are simply not reported in the registry record.
Safety figures are also limited to the posted counts. The adverse-event record lists zero participants with serious adverse events and three participants with other adverse events in the MALG Treatment Arm. These counts do not describe event types, timing, attribution, duration, or severity for the other events. The death field is not reported in the registry record. Counts from a study of this size are descriptive and do not, on their own, establish the presence or absence of uncommon risks.
Overall, the registry supports a description of the study design, intended blood-marker endpoint, sample-collection limitations, and posted adverse-event counts. It does not provide the numerical primary results needed to judge the observed cholinesterase changes or their precision. No conclusion about treatment benefit or lack of benefit can be drawn from the information reported in the registry.
9. Statistical Methods Explained
The endpoint is a continuous measure: percentage change in cholinesterase activity. The registry identifies the summary as a mean and the intended measure of uncertainty as a 95% confidence interval. It does not report the actual mean estimates, confidence limits, or the statistical procedure used to calculate them. The explanations below describe the general meaning of these methods, not a claim about which calculations were carried out for this study.
What does a mean percentage change represent?
A percentage change puts a post-treatment measurement in relation to its baseline value. The registry’s formula is (post-treatment value − baseline)/baseline × 100. It describes the measure as a reduction in cholinesterase activity. With the stated formula, a post-treatment value below baseline produces a negative change; the magnitude indicates the relative change from baseline. This is a within-person comparison before the values are summarized across the endpoint population.
The mean is an average across the observations included in an analysis. It offers a compact description of the group’s average change, but it does not show how much individual participants’ measurements differed from one another. A group mean can therefore coexist with substantial variation among participants. The registry does not report participant-level changes, a measure of spread, or the number of complete paired observations used for each biomarker analysis.
What does a confidence interval communicate?
In general, a confidence interval describes uncertainty around an estimated quantity under the assumptions of the method used. A narrower interval indicates greater precision for that estimate, while a wider interval indicates less precision. A 95% confidence interval is a statistical procedure with a repeated-sampling interpretation: if the same procedure were applied across repeated studies under its assumptions, the intervals would contain the underlying quantity at the stated rate. It is not a range containing 95% of individual participants’ measurements, nor does it guarantee that a particular interval contains the true value.
For this endpoint, the interval would be read alongside the mean percentage change for plasma or RBC cholinesterase. Its width would help readers judge how precisely that mean was estimated. The registry mentions narrow intervals in relation to established safety guidelines, but it does not report the guideline limits or the endpoint intervals. Thus, the rationale alone cannot show whether an estimate was near a guideline, within a specified range, or precise enough to support a particular interpretation.
Why do missing measurements matter?
A paired change uses a baseline value and a post-treatment value for the same participant. If either measurement is unavailable, that participant may not contribute a complete pair to the change calculation, depending on the analysis method. The record identifies unsuccessful post-treatment blood collection for subject 01-003 and subject 01-004 at the Day 0 assessment and reports 10 subjects with obtained blood samples. It does not state which of these observations were included in the plasma and RBC summaries, whether the same participants contributed to both summaries, or how missing data were handled.
Missingness can affect both the amount of information available and the interpretation of the estimate. If measurements are unavailable for reasons related to participant characteristics or observed outcomes, the analyzed observations may not represent all enrolled participants in the same way. This is a general statistical concern, not a finding that the missing samples in this study created bias. The registry does not report enough detail to assess the reason for missingness beyond the collection difficulties it describes.
What can the design estimate?
A single-group baseline-to-follow-up analysis estimates change over time among the observations analyzed. Without a separate comparator group, it does not estimate a contrast against an untreated or differently treated group. General influences on measurements over time cannot be distinguished from a treatment-associated change using the within-group change alone. This limitation follows from the design and does not depend on whether a mean change is large or small.
The registry lists 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. It specifies that an effect to detect is a stated fraction of the observed effect. These are planning assumptions, not results from the primary endpoint analysis and not the study’s recorded single-group design. Any sample-size values associated with such assumptions are planning illustrations, not observed power. The registry record does not report the original sample-size justification or a statistical analysis plan.
What is not available for statistical review?
The record reports seven outcome measures and zero analysis records, but does not supply numerical primary-endpoint estimates or their confidence intervals. It also does not report model details, distributional checks, or procedures for handling missing values and multiple outcomes. No particular statistical test or model should be inferred from the stated mean and confidence interval. In general, a confidence interval depends on both the data and the method used to construct it; without the method and results, readers cannot independently assess the estimate’s precision or verify its calculation.
10. Multiplicity, Missing Data and Analysis Populations
The registry counts seven outcome measures and lists local safety based on reported adverse events and observed scalp reactions as a secondary outcome. It does not report a multiplicity adjustment, a hierarchy among outcomes, or a plan for interpreting several statistical tests together. These details are not reported in the registry record. When several outcomes or comparisons are examined, the chance of at least one apparently notable result can increase; methods for controlling or interpreting that issue depend on the analysis plan. This is a general statistical consideration, not evidence that a particular multiplicity problem occurred in this study.
The registry reports zero analysis records. This indicates that no analysis details are listed in the record, but it does not establish that investigators conducted no analyses. The statistical plan, including any prespecified primary analysis and any interim analyses, is not reported in the registry record.
For the primary endpoint, the record reports 10 subjects with an obtained blood sample and describes unsuccessful post-treatment collection for subject 01-003 and subject 01-004 at Visit 1, Day 0. It does not state how these missing post-treatment measurements were handled, whether the endpoint used only complete baseline and follow-up pairs, or whether a method for incomplete data was applied. It also does not report analysis populations beyond the endpoint description’s statement about obtained blood samples. The reasons recorded for the collection difficulties do not establish that missingness was unrelated to the values that would have been observed.
These gaps limit assessment of which observations contributed to each endpoint, whether the analysis followed a prespecified plan, and how uncertainty was quantified. No missing-data or multiplicity method should be assumed where the registry record does not describe one.
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 |
|---|---|---|---|
| MALG Treatment Arm | 0 | 12 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| MALG Treatment Arm | 3 of 12 |
Most frequent non-serious adverse event terms
| Event term | Organ system | MALG Treatment Arm |
|---|---|---|
| Cough | Respiratory, thoracic and mediastinal disorders | 3 of 12 |
| Diarrhoea | Gastrointestinal disorders | 1 of 12 |
| Head injury | Injury, poisoning and procedural complications | 1 of 12 |
| Wheezing | Respiratory, thoracic and mediastinal disorders | 1 of 12 |
The adverse-event record lists 12 participants at risk for serious adverse events and zero participants affected. For other adverse events, it lists 12 participants at risk and three participants affected. These are participant counts as recorded for the MALG Treatment Arm; they are not descriptions of the number, type, or timing of individual events.
The record does not list any top serious adverse-event terms. It does not provide details for the other adverse events, such as their specific terms, severity, duration, relationship to treatment, or whether any participant had more than one event. The deaths field is not reported in the registry record. The secondary safety outcome also refers to observed scalp reactions, but numerical results for that outcome are not reported in the registry record.
A zero count for serious adverse events in this study is a description of the posted data, not proof that serious events cannot occur. Similarly, the other-event count cannot by itself characterize risk without event-level details and a suitable comparison. The small study context and the missing detail in the registry record make these counts descriptive rather than a complete assessment of safety.
12. What the Result Does, and Does Not, Mean
The registry record describes a study designed to assess safety and tolerability of a malathion formulation in children aged 6–24 months with head lice. Its primary endpoint focuses on mean percentage change in plasma and RBC cholinesterase activity from baseline to 1 hour after application. The record also describes blood measurements at 24 hours and a secondary outcome concerning local safety based on adverse events and observed scalp reactions.
The posted information does not report numerical mean changes or 95% confidence intervals for the primary endpoint. It therefore does not show the magnitude, direction, or precision of the observed changes. The stated rationale connects interval width to established safety guidelines, but neither the intervals nor the relevant guideline limits are reported. The endpoint rationale should not be mistaken for a reported finding.
The safety record lists zero participants with serious adverse events and three participants with other adverse events, among the listed participants at risk. It does not identify the other events or report their characteristics. These counts provide limited descriptive information and do not establish that an event is caused by the treatment or that an event cannot occur.
The study has one treatment group and no randomized comparator. A within-group change from baseline, even if its numerical estimate were available, would not by itself distinguish treatment-related change from other influences over time. The registry does not report a comparison that could answer that separate question.
Accordingly, the record documents the intended measures, the study structure, sample-collection difficulties, and limited adverse-event counts. It does not provide enough numerical endpoint or analysis information to assess the primary result’s size and precision. It does not establish efficacy, a definitive safety profile, or a causal effect. Those conclusions cannot be drawn from the registry information reported.
13. Why This Trial Matters Statistically
This study is statistically notable for the question it set out to measure in a young population: change in plasma and RBC cholinesterase after application of a malathion formulation. The endpoint uses repeated measurements, comparing post-treatment values with baseline for the same participant. That makes sample collection at each scheduled time important, because a change requires corresponding measurements that can be paired.
The endpoint description makes the practical measurement issue visible: it reports 10 subjects with an obtained blood sample and identifies difficulties obtaining post-treatment samples for subject 01-003 and subject 01-004 at the Day 0 visit. Such details matter when interpreting a mean, since the observations included in an analysis determine whose changes contribute to the estimate. The registry record does not explain how the incomplete measurements were handled, so the exact analysis population and potential effect of missingness remain unclear.
The record also illustrates why an estimate and its uncertainty are both important. A mean percentage change would describe an average, while a confidence interval would convey precision under the method’s assumptions. Yet the numerical estimates and intervals are not reported, so neither the average observed change nor its precision can be evaluated from the registry record.
Finally, the single-group design and limited adverse-event detail constrain interpretation. The record offers no randomized comparator for attributing changes to treatment, and posted event counts do not describe event characteristics. The statistical importance of the study therefore lies in its measurement question and in the information needed to interpret it, as well as in the limits imposed by unreported results and analysis details.
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 the primary endpoint is that its numerical results are not reported in the registry record. The mean percentage changes for plasma and RBC cholinesterase and their 95% confidence intervals are absent. The stated aim of relating interval width to safety guidelines cannot be evaluated without the estimates and guideline limits.
The endpoint description reports 10 subjects with obtained blood samples and records unsuccessful post-treatment collection for subject 01-003 and subject 01-004 at Visit 1, Day 0. It does not specify which measurements were available for each biomarker, how many complete baseline-to-follow-up pairs contributed to each estimate, or how missing values were handled. This limits assessment of the analysis population and the possible influence of incomplete measurements.
The study is non-randomized, open-label, and single group, with no separate comparator arm. Any baseline-to-follow-up change would therefore lack a concurrent control comparison. The registry does not report the statistical analysis plan, details of the analysis method, or procedures for multiplicity. It lists seven outcome measures and zero analysis records, leaving those issues unresolved in the registry record.
Safety information is also limited. The record lists zero participants with serious adverse events and three with other adverse events, but provides no terms for those other events or details about severity, timing, attribution, or duration. The deaths field is not reported in the registry record, and numerical results for the local scalp-reaction outcome are not given.
These limitations concern what can be assessed from the registry record. They do not establish that the study lacked additional data or analyses outside the record, but such information is not reported in the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Safety and Tolerability of a Novel Malathion Formulation in Children Age 6-24 Months With Head Lice — NCT00752973.
- Registry record last updated 2014-08-07; status last verified 2014-07.
- Results first posted 2014-04-03.
- 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
NCT00752973 is a completed, multi-center, open-label study of MALG treatment in children aged 6–24 months with pediculosis capitis. The registry lists Phase II and Phase III, non-randomized allocation, and a single-group model. Enrollment is recorded as 12.
The primary endpoint is mean percentage change in plasma and RBC cholinesterase from baseline to 1 hour after application. The record reports 10 subjects with obtained blood samples and describes post-treatment collection difficulties for subject 01-003 and subject 01-004. Numerical endpoint estimates and confidence intervals are not reported in the registry record.
The adverse-event record lists zero participants with serious adverse events and three with other adverse events in the treatment arm. Event details and the deaths field are not reported in the registry record. The record lists seven outcome measures and no analysis records.