STOPAIN in the Treatment of a Single Migraine Attack: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for STOPAIN in the Treatment of a Single Migraine Attack (NCT01687101), a na na study. The primary outcome is Efficacy of STOPAIN in the Acute Treatment of Migraine.

2. Clinical Question

This is a question about an acute outcome after treatment, not about preventing future attacks or comparing STOPAIN with another treatment. The stated primary outcome is pain freedom at a specific time point. The record describes the scale as four-point, from 0 for no pain to 3 for severe pain, and identifies the assessment time as 2 hours after gel application.

Because there is no control group, the study cannot directly estimate how the outcome would differ under another treatment or no treatment. Its design can describe what was recorded among participants who used the gel, but a change after application by itself cannot establish that the gel caused the change. The outcome value, the number meeting the pain-freedom definition, and any estimate of uncertainty are not reported in the registry record.

3. Trial Design

The registry describes a completed pilot study of STOPAIN topical gel in the acute treatment of one migraine attack. It lists the model as single-group, allocation as NA, and masking as none. The design is open label: participants and study personnel were not masked to the intervention, according to the record. There is no randomized comparison or like-for-like control group.

The registry enrollment is 32. The brief summary, however, describes a plan involving 25 subjects with episodic migraine, with or without aura. These are different figures in the record; an explanation of their relationship is not reported in the registry record. The record lists a start of 2012-05, a primary completion of 2013-05, and status as completed. The phase is listed as NA.

The intervention is described as topical menthol 6% gel. The stated instructions are 2 to 4 pumps applied behind the ears and to the occipital region of the neck, in one or two applications within 2 hours of migraine onset. The registry does not report further details about adherence, other permitted treatments, or how application timing was handled in analysis.

The primary outcome is pain freedom at 2 hours after gel application. Although one outcome measure is listed, the registry record reports zero analyses. It does not report an efficacy estimate, a statistical test, or a confidence interval. The protocol’s planned analysis, including any analysis population or handling of incomplete assessments, is not reported in the registry record. The study’s pilot and single-group features are important when interpreting the limited information available: this design can describe observations but does not provide a randomized treatment contrast.

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

Reasons for not completing this period:

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 Efficacy of STOPAIN in the Acute Treatment of Migraine, measured over 2 hours after the time of gel application.

The primary outcome is titled “Efficacy of STOPAIN in the Acute Treatment of Migraine.” Its description defines pain freedom as a headache pain-intensity level equal to “no pain” at 2 hours after the gel application. The scale is described as having four values: 0=no pain, 1=mild pain, 2=moderate pain, and 3=severe pain. Thus, the stated pain-freedom condition corresponds to the no-pain response at the specified assessment time.

A fixed-time outcome can make the question clinically and statistically concrete: it asks about a defined state at a defined interval following treatment, rather than an unspecified impression of improvement. A threshold such as no pain also differs from measuring average pain intensity. A person can have a lower score without reaching the no-pain threshold, so those are distinct ways to describe symptoms.

The record’s outcome fields are not fully aligned in their wording. The narrative defines pain freedom using a point on the four-point scale, while the outcome is also labeled as a mean with full-range dispersion and units on a scale. The record does not explain whether the intended analysis was of the scale score, the proportion at the no-pain level, or another summary. No observed outcome value or count attaining pain freedom is reported in the registry record, so the endpoint definition can be described but its result cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical interpretation begins with the design. This is a single-group study: the registry does not identify a concurrent control group or a randomized allocation. In a controlled comparison, the statistical contrast is between outcomes in different assigned groups. In a single-group study, the observed outcome can be summarized, but there is no randomized between-group contrast to separate the intervention’s effect from changes that might occur over time or other influences. This is a general limitation of the design, not a finding about what happened to participants in this trial.

What does the outcome definition imply?

The primary outcome description identifies a four-point pain scale and defines pain freedom as a score of 0, “no pain,” at 2 hours after gel application. The scale is ordered: its values represent increasing levels from no pain to severe pain. An analysis of the full scale and an analysis of whether the score is exactly 0 would answer different questions. A mean score summarizes the scale numerically, whereas pain freedom focuses on whether an individual meets a threshold. The registry labels the outcome as a mean with full-range dispersion, but its narrative emphasizes the threshold. Which analysis was intended is not reported in the registry record.

For a mean, a measure of dispersion describes how spread out observations are around the center. A full range records the smallest and largest observed values. General statistical explanation: a range is sensitive to the most extreme observations and does not show the distribution between those extremes. For an ordered, bounded scale, the choice of summary matters because numerical averages do not fully describe how many participants were at each level. The posted record does not provide the outcome distribution or a summary value.

Why does uncertainty matter?

An estimate from a study is subject to sampling variability: another sample from a similar population may produce a different result. A confidence interval is a statistical range expressing uncertainty around an estimate under the assumptions of the method used. A narrow interval indicates greater precision than a wide interval, while neither alone establishes whether an observed association is causal. The registry record does not report an efficacy estimate or confidence interval, so the precision of the primary outcome cannot be assessed.

A p-value, when reported, measures how compatible data are with a specified null model and analysis assumptions. It is not the probability that a treatment works, and it does not describe the size or practical importance of an effect. No efficacy p-value or statistical test is reported in the registry record. Therefore, there is no reported test result to interpret. The absence of a posted analysis is not evidence that a particular statistical result was or was not obtained.

How should planning illustrations be read?

The assumptions for the planning illustrations describe a hypothetical two-arm design, with equal allocation, a two-sided significance level of 0.05, and a normal approximation. They also frame the effect to detect as a stated fraction of the observed effect. This is distinct from the actual single-group design, which has no two-arm randomized comparison. The illustrations are planning calculations, not observed study outcomes and not observed power. Sample sizes under such assumptions indicate what a hypothetical design might require under those assumptions; they do not show the probability that this completed study detected an effect.

General statistical explanation: a normal approximation is a modeling choice, and its usefulness depends on the outcome and the sampling distribution. A bounded four-point scale and a threshold outcome have features that may differ from an unbounded continuous measurement. The registry does not report the analysis model, diagnostics, or rationale for a model used in the trial. The assumptions attached to planning calculations should not be mistaken for the trial’s analysis plan.

What is missing from the analysis record?

The registry lists one outcome measure and zero analyses. It does not report how the primary outcome was summarized, what statistical test or model was used, whether an adjustment was made, or which participants were included in an analysis. It also does not report how missing assessments or protocol deviations were handled. These omissions prevent reconstruction of an inferential result from the registry record.

General statistical explanation: analysis choices should be prespecified where possible, because choices about the outcome definition, timing, population, and model can affect estimates and uncertainty. When those details are unavailable, readers cannot evaluate whether a reported estimate follows a planned approach or how sensitive it might be to alternative reasonable choices. Here, the efficacy result and analysis details are not reported in the registry record; accordingly, there is no basis for interpreting a trial-specific effect estimate, confidence interval, or p-value.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists one outcome measure, the pain-freedom outcome at 2 hours, and zero analyses. The record does not describe a multiplicity plan, such as how it would handle testing more than one outcome, time point, subgroup, or analysis. It also does not report whether any interim analyses were planned or conducted. These details are not reported in the registry record.

General statistical explanation: when several statistical tests are conducted, the chance of at least one apparently notable result can increase if each test is interpreted independently. A prespecified strategy can address that issue, for example by defining a primary outcome and limiting confirmatory testing or by adjusting inference. The existence of one listed outcome measure does not by itself establish that only one analysis was performed; the registry lists no analyses and does not describe the complete analysis plan.

Missing-data handling is also not described. The record does not state how many participants had an evaluable assessment at 2 hours, how incomplete outcome measurements were treated, or whether any participants were excluded from an analysis. These details are not reported in the registry record. General statistical explanation: missing observations can affect both the estimate and its uncertainty, especially when the reasons for missingness are related to the outcome. Knowing the number assessed and the approach to missing data is therefore important for interpreting a result.

The analysis population is not reported in the registry record. There is no description of an intention-to-treat population, a per-protocol population, or another defined set of participants for efficacy analysis. The registry enrollment is 32, but enrollment alone does not establish how many contributed to the primary outcome analysis. Without a stated population and denominator, the completeness and scope of any efficacy summary cannot be evaluated.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 2% reporting threshold.

Most frequent non-serious adverse event terms

For the STOPAIN topical gel group, the registry lists 32 participants at risk for serious adverse events and 0 affected. It lists 32 at risk for other adverse events and 2 affected. The record does not list any serious adverse-event terms. A death count is not reported in the registry record.

These entries are counts recorded for this study group. They should not be read as a comparison with another treatment, because the study has no comparator group. The entries also do not establish whether an event was caused by the gel: the record does not provide event descriptions, attribution details, or a comparative analysis. The phrase “other adverse events” is not further characterized in the registry record, so the nature and severity of those events cannot be interpreted from the counts alone.

General statistical explanation: event counts are most informative when the definitions, observation period, ascertainment methods, and participant denominators are clear. The group figures give at-risk counts, but the registry does not report additional detail on follow-up or how events were collected. The counts describe the posted safety information; they should not be taken as a comprehensive estimate of risk.

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

The record establishes that a completed, open-label, single-group pilot study evaluated STOPAIN topical gel for a single migraine attack. It specifies the application instructions and defines the primary outcome as pain freedom, or no pain on a four-point scale, at 2 hours after application. It also records enrollment of 32 and lists adverse-event counts for the intervention group.

Those design and outcome details do not establish what the study found on its primary efficacy question. The primary outcome value, the number of participants who were pain-free, and any estimate of uncertainty are not reported in the registry record. The record lists zero analyses. Consequently, a reader cannot determine from this record the frequency of pain freedom, the distribution of pain scores, or the precision of an efficacy estimate.

Even if a descriptive outcome value were available, the design would not provide a randomized comparison. General statistical explanation: without a control group, a before-and-after observation cannot distinguish an intervention-related change from changes that might have occurred with time or other influences. Open-label assessment can also be susceptible to expectation effects, depending on how outcomes are collected. These are general interpretive cautions, not claims about the conduct or participants in this study.

The safety entries are similarly limited: 0 participants are listed as affected by serious adverse events among 32 at risk, and 2 by other adverse events among 32 at risk. The record does not provide detail sufficient to characterize those other events or make a comparative safety assessment. The data therefore support a narrow description of the registered design and recorded counts, but not a conclusion about efficacy or a broad estimate of safety.

The planning illustrations are not evidence of what occurred in the trial. Their assumptions describe a hypothetical two-arm calculation, whereas the study is single-group. They are not observed power and do not supply the missing efficacy result. The record’s most important interpretive boundary is that it documents the question and design without reporting the analysis needed to answer that question.

13. Why This Trial Matters Statistically

This trial illustrates why study design and outcome reporting must be read together. The record defines a focused, time-specific endpoint—pain freedom at 2 hours—but does not report the value or analysis for that endpoint. A clear outcome definition helps identify what investigators intended to measure; it cannot replace the observed result, denominator, or uncertainty estimate needed to interpret what was measured.

The single-group, open-label structure also makes the target of inference important. A description of outcomes among participants who used the gel is not equivalent to an estimate of the difference between treatment and control. General statistical explanation: causal comparisons are strengthened when assignment creates groups that differ mainly in the intervention received. Without a comparator, the observed experience cannot by itself separate treatment effects from the course of symptoms or other influences.

The record also shows how planning calculations can be detached from the design they are meant to inform. The stated planning assumptions describe equal allocation between two arms and a normal approximation, while the registered trial is single-group. Such illustrations may be useful as hypothetical planning exercises, but they are not evidence of study power or a substitute for a reported analysis.

Finally, the record makes the difference between outcome definitions and statistical summaries visible. The narrative identifies a no-pain threshold, while the outcome fields label a mean and full-range dispersion. Because the intended analytic summary is not clarified, the planned estimand cannot be fully reconstructed. For clinical research readers, this case underscores the value of aligning the question, outcome definition, analysis method, and posted results.

14. Limitations

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

Several limitations specific to this trial are evident from the registry record. First, the study is single-group and open label, with no comparator and no randomized allocation. It can therefore provide no direct controlled estimate of the difference associated with STOPAIN versus another condition. The record describes an acute-use pilot, rather than a comparative trial.

Second, the main efficacy result is not reported. Although the primary outcome is defined, the record does not include an observed pain-freedom count, scale summary, effect estimate, confidence interval, or p-value. It lists zero analyses. This prevents assessment of both the direction and precision of the primary outcome.

Third, outcome specification is not entirely clear. The narrative describes pain freedom as a score of 0 on a four-point scale, but the outcome is labeled as a mean with full-range dispersion. The registry does not explain how those descriptions relate to the intended analysis. The analysis population, missing-data approach, and handling of deviations are also not reported in the registry record.

Fourth, the brief summary refers to 25 subjects, while the registry enrollment is 32. The record does not explain the relationship between these figures. It also does not report further participant characteristics, assessment completeness, or additional details of the intervention’s use beyond the stated application instructions.

Finally, safety information is limited to counts: 0 affected by serious adverse events and 2 affected by other adverse events, with 32 at risk in each category. Event details are not reported, and there is no comparison group. These limitations restrict interpretation of both efficacy and safety to the information explicitly recorded.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: STOPAIN in the Treatment of a Single Migraine Attack — NCT01687101.
• Registry record last updated 2017-06-09; status last verified 2017-05.
• Results first posted 2015-04-27.
• 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, open-label, single-group pilot study of STOPAIN topical gel for one migraine attack. The intervention is topical menthol 6%, applied as 2 to 4 pumps behind the ears and to the occipital region of the neck, in one or two applications within 2 hours of migraine onset. The listed enrollment is 32; the brief summary refers to 25 subjects with episodic migraine, with or without aura.

The primary outcome is pain freedom, defined as no pain on a four-point scale, at 2 hours after gel application. The record lists one outcome measure and zero analyses. No primary efficacy result or uncertainty estimate is reported in the registry record. The safety entries list 0 participants affected by serious adverse events and 2 affected by other adverse events, with 32 at risk for each category. The study has no comparator, so the record does not provide a randomized treatment contrast.