Efficacy and Safety of a New Dilution and Injection Volume of AbobotulinumtoxinA for the Treatment of Glabellar Lines: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Efficacy and Safety of a New Dilution and Injection Volume of AbobotulinumtoxinA for the Treatment of Glabellar Lines (NCT03960957), a randomized phase 3 study. The primary outcome is Evaluate Composite Responder Rate at Month 1 for a Single Dose of AbobotulinumtoxinA Compared to Placebo.

2. Clinical Question

3. Trial Design

The registry describes NCT03960957 as a randomized, double-blind, parallel-group phase 3 study. Its official title calls it a multicenter, randomized, double-blind, placebo-controlled study. It evaluated a new dilution and injection volume of AbobotulinumtoxinA for moderate to severe glabellar lines, with placebo as the comparator. The experimental arm is identified as AbobotulinumtoxinA, and the other arm is identified as Placebo.

The registry lists enrollment as 301. For the primary outcome, the posted arm summaries use 224 participants in the experimental arm and 77 in the placebo arm. The record does not explain the relationship between the enrollment figure and the outcome denominators, or state whether participants without outcome data were excluded. Reasons for any difference between enrollment and the primary outcome denominators are not reported in the registry record.

The study began on 2019-06-17, reached primary completion on 2019-09-27, and is marked COMPLETED. These dates describe the trial record and do not establish when results were analyzed or submitted. The registry lists Galderma R&D as sponsor. It lists AbobotulinumtoxinA as a biological intervention and Placebo as another intervention.

Randomization and double masking describe important design features, but the registry record does not state the allocation sequence method, allocation concealment procedures, who was masked, or how masking was maintained. It also does not report the planned sample-size justification, a statistical analysis plan, or whether interim analyses were conducted. The record identifies the primary endpoint and timeframe but does not provide enough detail to reconstruct the full protocol or analysis population.

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

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.

6. Primary Endpoint

The registry lists the primary outcome as Evaluate Composite Responder Rate at Month 1 for a Single Dose of AbobotulinumtoxinA Compared to Placebo, measured over Month 1 after treatment.

The primary endpoint is the number of participants meeting a composite response definition at Month 1 after treatment. A participant was counted as a responder only if the participant achieved a score of 0 or 1 and at least 2 grades of improvement on both the Investigator Live Assessment and the Subject Self Assessment. Thus, the outcome requires qualifying results on both assessments rather than success on either assessment alone.

A composite endpoint can bring multiple dimensions of assessment into a single criterion. In this trial, combining investigator and participant assessments makes the endpoint depend on both perspectives, while the score and improvement requirements define what counts as a response. This may be useful when the research question is about a response that should meet both assessment criteria. The registry does not report why this particular threshold or combination was selected, so the rationale for those choices is not reported in the registry record.

The endpoint is binary at the participant level: each participant either meets the composite definition or does not. The posted results report counts in each arm, which allow the responder proportions and their between-arm contrast to be described. The outcome is assessed at Month 1 after treatment; the registry does not establish what happened at other times. A result at this timepoint should therefore be interpreted as a comparison for the specified endpoint and timeframe, not as a summary of outcomes across the full course of follow-up.

7. Results Posted in the Registry

• Experimental: 63.4% (142/224) versus 0.0% (0/77) on control; risk difference 63.4 percentage points (95% CI 57.1 to 69.7); unadjusted two-proportion z-test p = <0.001.

8. Statistical Interpretation

9. Statistical Methods Explained

The main result is a comparison of a binary participant-level outcome: meeting or not meeting the composite responder definition. For a binary endpoint, each arm can be described by a responder count and the number of participants included in that outcome summary. The registry reports 142 responders among 224 participants in the experimental arm and 0 among 77 participants in the placebo arm. The reported contrast is a risk difference of 0.634.

What does a risk difference represent?

As a general statistical concept, a risk difference subtracts one arm's event proportion from the other arm's event proportion. It expresses an absolute contrast on the probability scale, rather than a relative comparison. Here, the registry reports the risk difference directly; no new contrast needs to be calculated from the arm counts. The registry gives the arm ordering as experimental compared with placebo. The estimate should be read with its confidence interval and the endpoint definition, rather than in isolation.

Zero responders are reported in the placebo arm. A zero count is a feature of the observed data, not proof that the underlying probability is exactly zero. Estimates and uncertainty can be sensitive when an arm has no observed events, and a particular statistical method may handle that situation differently from another. The registry does not report the method used to derive the risk difference interval or p-value, so the calculation cannot be independently reconstructed from the record alone.

What does the p-value address?

In general, a p-value describes how incompatible the observed data, or data more extreme, are with a specified statistical null model, assuming that model and its assumptions. It is not the probability that the null hypothesis is true, nor does it measure the size or practical importance of an effect. The registry reports p < 0.001 for the comparison. The exact test, its assumptions, and whether the test was prespecified are not reported in the registry record. The p-value should therefore be presented as reported, without attributing it to a particular procedure.

The reported confidence interval runs from 0.571 to 0.697 around the risk difference of 0.634. As a general concept, a confidence interval gives a range of estimates compatible with the data under the method's assumptions and reflects sampling uncertainty. It does not include all possible sources of uncertainty, such as outcome measurement issues, missing data, selection effects, or limitations in the trial design. Its interpretation also depends on the method used to construct it, which is not reported in the registry record.

What can be inferred about the analysis plan?

The registry lists 1 outcome measure and 0 analyses. The primary outcome is identified, but a detailed statistical analysis plan is not reported in the registry record. In particular, the record does not describe the test or model, any covariate adjustment, handling of missing outcome data, or the analysis population. It also does not report whether interim analyses were conducted. Randomization supports a between-arm comparison in design, but it does not supply missing details about the analysis actually performed.

The outcome denominators are 224 in the experimental arm and 77 in the placebo arm, while enrollment is listed as 301. The record does not explain the denominators or identify the disposition of participants who may not be represented in the primary outcome summaries. It would be inappropriate to infer that all randomized participants were included, or that missing assessments were treated in a particular way. A reader can describe the posted denominators and counts, while recognizing that the analysis-population details are not reported in the registry record.

How should planning illustrations be read?

As a general concept, power calculations estimate the sample size needed to detect a specified effect under stated assumptions. Any planning illustrations based on an observed effect are not a measure of the trial's observed power and should not be interpreted as a feature of the original design. The stated illustration assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is a stated fraction of the observed effect. For time-to-event outcomes, the illustration convention is a total number of events; other outcomes use participants per arm. This trial's primary outcome is binary, so planning quantities for this endpoint are expressed as participants per arm. Such calculations are hypothetical planning aids, not evidence about the trial's design justification or the certainty of its observed result.

The registry does not report the trial's own sample-size justification, its target power, or assumptions used by the investigators. The planning assumptions should not be attributed to the protocol. Nor should a planning calculation based on the observed contrast be used as a retrospective claim that the study had a particular probability of detecting an effect. The registry record does not provide sufficient information to evaluate those design decisions.

10. Confidence Intervals and Precision

The registry reports a risk difference of 0.634 and a 95% confidence interval from 0.571 to 0.697 for the Month 1 composite responder outcome. The interval describes the statistical precision of the estimated absolute contrast under the method used to calculate it. The point estimate is a single value; the interval communicates that sampling variability means other values are also compatible with the data and the interval procedure's assumptions.

The reported interval does not cross zero. In the context of a risk difference, zero corresponds to no difference between arm proportions. This alignment with p < 0.001 is consistent with a statistically distinguishable contrast under the reported analysis. It does not mean that uncertainty is absent, or that the interval accounts for all potential sources of bias. Confidence intervals reflect uncertainty modeled by their calculation, not uncertainties that the registry does not describe.

The precision should also be considered in light of the observed outcome counts: the experimental arm has 142 responders among 224 participants, and the placebo arm has 0 among 77. The unequal arm denominators and the absence of observed placebo responders are features of the posted data. The registry does not state the interval method, so it is not possible to assess from the record whether alternative methods would produce different limits, particularly given the zero count in one arm.

The interval is specific to the responder definition and Month 1 timeframe. It does not quantify uncertainty about a different endpoint, a later assessment, or the generalizability of the trial population. Nor does it resolve the missing information about outcome completeness and analysis population. It is best read as precision for the reported comparison, conditional on the analysis and assumptions that produced it; those calculation details are not reported in the registry record.

11. Multiplicity, Missing Data and Analysis Populations

The registry identifies the primary endpoint as the composite responder rate at Month 1 after treatment. It lists 1 outcome measure and 0 analyses, and no secondary outcomes are posted. The registry record does not describe a multiplicity strategy, such as how statistical error would be handled if multiple outcomes, timepoints, or comparisons were tested. It is therefore not possible to establish whether the reported p-value was adjusted for multiple testing or whether any adjustment was planned. The registry does not report a broader statistical analysis plan.

Multiplicity is a general concern when investigators conduct multiple statistical tests: the chance of at least one apparently notable result can increase as the number of tests grows, depending on the testing framework. Identifying a primary endpoint can help distinguish the main question from other analyses, but the record alone does not establish how all planned tests were controlled. Since secondary results and analysis details are not reported, the extent of testing cannot be determined from the registry record.

The outcome summaries include denominators of 224 in the experimental arm and 77 in the placebo arm, while enrollment is listed as 301. The registry does not explain whether participants lacked assessments, were excluded from the outcome analysis, or were handled by another approach. The missing-data methods, number of missing outcomes, reasons for missingness, and any sensitivity analyses are not reported in the registry record. No particular approach, such as imputation or complete-case analysis, should be assumed.

The record also does not name the primary analysis population or state whether the analysis followed randomized assignment. This limits assessment of how the posted comparison relates to the randomized design. The reported counts remain interpretable as the registry's outcome summaries, but the analysis population and completeness of assessment cannot be established from the available record.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: worsening knee pain (0.4%), acute diverticulitis (0.4%), long qt syndrome (0.4%), worsening of hemorrhoids (0.4%).

The registry reports serious adverse events for 4 participants at risk in the experimental arm and 0 participants at risk in the placebo arm. The denominators at risk are 223 and 77, respectively. The record lists Worsening knee pain, Acute diverticulitis, Long QT syndrome, and Worsening of hemorrhoids among the serious event terms, each at 0.4%. These terms are registry summaries; the record does not provide further detail about timing, duration, severity, relatedness to treatment, or the number of events represented by each term.

Other adverse events are listed separately: 24 participants at risk in the experimental arm and 6 in the placebo arm were affected, using denominators at risk of 223 and 77. Deaths are reported as 0 in both arms. Serious and other adverse events are different summary categories in the registry and should not be combined or treated as interchangeable. The registry record does not describe event collection procedures, follow-up completeness, or how events were judged to be serious.

These counts are descriptive. They do not by themselves establish whether an event was caused by the intervention or whether the observed arm differences reflect treatment, chance, or other factors. The record does not provide sufficient detail to infer a comprehensive safety profile. Interpretation should remain limited to the posted categories, counts, denominators, and event terms.

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

The posted primary outcome shows that the composite response criterion was met by 142 participants among 224 in the AbobotulinumtoxinA arm and by 0 among 77 in the placebo arm at Month 1 after treatment. The registry reports a risk difference of 0.634, a 95% confidence interval from 0.571 to 0.697, and p < 0.001. These results describe a substantial observed separation in the responder proportions for this defined endpoint at this specified timepoint.

The result is not a guarantee that an individual participant will meet the response criterion. A group-level estimate summarizes the trial participants' observed outcomes, and its interpretation depends on the trial population, measurement definitions, follow-up, and analysis. The record does not provide enough information about eligibility details, outcome completeness, or the primary analysis population to resolve all questions about those features.

The endpoint requires a score of 0 or 1 and at least 2 grades of improvement on both the Investigator Live Assessment and Subject Self Assessment. Consequently, the result pertains to this combined threshold rather than every possible measure of glabellar lines, participant experience, or treatment response. The registry does not report secondary outcome results or results at other timepoints, so the primary result cannot stand in for unreported measures.

A small p-value does not measure clinical importance, establish the absence of bias, or show that every assumption is satisfied. Likewise, the confidence interval describes precision under its calculation method but does not address all limitations of design or reporting. The method used for the reported interval and test is not reported in the registry record. Safety should also be considered separately: the registry lists serious and other adverse events and deaths, but the summaries do not establish causality or provide a complete account of safety.

In short, the registry supports a statistical description of the posted primary comparison and its reported uncertainty. It does not by itself answer questions about longer-term outcomes, broader applicability, participant-level prediction, or unreported aspects of trial conduct and analysis.

14. Why This Trial Matters Statistically

This trial is statistically notable as a randomized, double-blind, placebo-controlled phase 3 comparison with a clearly described composite binary endpoint. Its responder definition combines investigator and participant assessments, requiring both to meet specified criteria. That makes the statistical question concrete: how do the proportions satisfying the entire composite definition compare between the randomized arms at Month 1 after treatment?

The registry reports a risk difference of 0.634 with a confidence interval from 0.571 to 0.697 and p < 0.001. Reporting an absolute contrast together with an interval allows readers to consider both the estimated magnitude and its statistical precision. The arm summaries also make the basis of the comparison visible: 142 responders among 224 participants in the experimental arm and 0 among 77 in the placebo arm.

The record illustrates why a result must be interpreted alongside its endpoint definition, denominators, and analysis details. A composite outcome can be informative while also narrowing what the result means to the criteria it includes. Unequal outcome denominators and the lack of reported analysis-population and missing-data methods leave important questions unresolved. The registry does not state how the interval and p-value were calculated, so their exact statistical procedures cannot be assessed from the record.

It also illustrates the difference between evidence about an observed result and assumptions used for planning. Planning calculations based on the observed effect are hypothetical illustrations, not observed power and not the investigators' sample-size rationale. The trial's own sample-size justification and statistical plan are not reported in the registry record. These distinctions are relevant when judging how far the posted result supports statistical conclusions.

15. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry record leaves important details of trial conduct and analysis unspecified. It identifies the study as randomized and double-blind, but does not describe the randomization sequence, allocation concealment, which parties were masked, or procedures used to maintain masking. It names a multicenter design, but does not report the number or locations of centers. These details are not reported in the registry record and cannot be inferred from the design labels.

The outcome denominator differs by arm, and the registry does not explain the relationship between those outcome summaries and enrollment of 301. Reasons for any participants not represented in the primary outcome counts, the number with missing assessments, and missing-data handling are not reported. The primary analysis population is also not identified. These gaps limit evaluation of whether the summaries reflect all randomized participants and how missing observations may have affected the comparison.

The reported risk difference and p-value are not accompanied by the statistical test or model, interval-construction method, or a detailed analysis plan. The registry does not report covariate adjustment, interim analyses, or the investigators' sample-size justification. Although the primary outcome is named, multiplicity procedures are not described, and no secondary results are posted.

The endpoint is specific to the composite assessment criteria and Month 1 after treatment. The registry does not provide evidence about other outcome definitions or timepoints. Safety summaries lack event-level context, including timing, duration, relatedness, and ascertainment methods. These limitations do not alter the posted counts, but they constrain how broadly the result and safety information can be interpreted.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Efficacy and Safety of a New Dilution and Injection Volume of AbobotulinumtoxinA for the Treatment of Glabellar Lines — NCT03960957.
• Registry record last updated 2022-08-26; status last verified 2021-05.
• 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.

19. Record Summary

NCT03960957 is a completed phase 3 randomized, double-blind, parallel-group, placebo-controlled study of AbobotulinumtoxinA for moderate to severe glabellar lines. The record lists enrollment of 301, a start date of 2019-06-17, primary completion on 2019-09-27, and Galderma R&D as sponsor.

The primary endpoint was the composite responder count at Month 1 after treatment. The posted results list 142 responders among 224 participants in the experimental arm and 0 among 77 in the placebo arm. The reported risk difference is 0.634, with a 95% confidence interval from 0.571 to 0.697 and p < 0.001.

The registry lists serious adverse events affecting 4 participants at risk in the experimental arm and 0 in the placebo arm, other adverse events affecting 24 and 6, respectively, and 0 deaths in each arm. It lists 1 outcome measure, 0 analyses, and no secondary outcome results. The statistical plan, missing-data methods, and analysis population are not reported in the registry record.