This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
EPITHET was a randomized, double-masked, parallel phase 2 treatment trial evaluating alteplase t-PA in stroke. The study was designed to examine whether thrombolysis attenuated lesion growth in patients with penumbra.
| Feature | EPITHET |
|---|---|
| NCT ID | NCT00238537 |
| Acronym | EPITHET |
| Full title | Echoplanar Imaging Thrombolysis Evaluation Trial |
| Condition | Stroke |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Double |
| Primary purpose | Treatment |
| Lead sponsor | Melbourne Health |
2. Clinical Question
Population
Patients with stroke enrolled in the EPITHET study.
Intervention
Alteplase t-PA (drug).
Comparator
The randomized comparison evaluated alteplase t-PA treatment.
Primary question
In patients with penumbra, will tPA attenuate lesion growth?
3. Trial Design
Patients were assigned in a randomized trial design.
The study used double masking.
The design model was parallel.
The registry reports enrollment of 100 participants.
4. Endpoints
| Endpoint | Registry definition |
|---|---|
| Primary Hypothesis - lesion growth | Primary hypothesis endpoint. |
| Lesion growth attenuation | In patients with penumbra, there will be attenuation of lesion growth (outcome T2 lesion volume - acute DWI volume) with tPA. |
5. Planned Analysis
The ClinicalTrials.gov record does not report posted statistical analyses or trial results. The registry identifies lesion growth as the primary hypothesis and describes the outcome as the difference between T2 lesion volume and acute DWI volume.
For an imaging-based lesion-growth endpoint, a statistical analysis would typically compare the distribution of lesion growth measurements between randomized groups. Depending on the prespecified analysis plan, this type of continuous outcome may be evaluated using methods such as comparison of group means or adjusted regression models. The appropriate analysis depends on the assumptions and statistical plan defined before unblinding.
6. Statistical Methodology
Randomization
Randomization is the foundation of the treatment comparison because it is intended to balance measured and unmeasured prognostic factors between groups. In a randomized phase 2 trial, the observed difference in outcomes is interpreted within the context of that allocation process.
Continuous imaging outcomes
The primary endpoint uses lesion volume measurements. Continuous outcomes are commonly summarized using measures such as means, standard deviations, medians, and confidence intervals, with formal comparisons defined by the statistical analysis plan.
Confidence intervals
A confidence interval describes uncertainty around an estimated treatment effect. It provides information about precision and should be interpreted together with the magnitude of the observed effect.
7. Statistical Methods Explained
Why measure lesion growth?
Lesion growth provides an imaging-based measure of disease progression after stroke and can be used as a quantitative outcome.
What does attenuation of lesion growth mean?
It refers to a reduction in the increase in lesion volume between imaging assessments.
Why is randomization important?
Randomization supports unbiased comparison by assigning treatment independently of patient characteristics.
Why are confidence intervals important?
Confidence intervals show how precisely an estimated treatment difference has been measured.
Why are imaging outcomes statistically challenging?
Imaging measurements require consistent acquisition, measurement definitions, and appropriate statistical handling of variability.
8. Limitations
- The ClinicalTrials.gov record does not report posted statistical analyses.
- Effect estimates, confidence intervals, and p-values are not reported in the registry record.
- The primary endpoint depends on quantitative imaging measurements, which require careful measurement methodology.
- Phase 2 studies are generally designed to evaluate preliminary evidence rather than provide definitive clinical conclusions.
9. Why This Trial Matters Statistically
EPITHET illustrates several important concepts in clinical trial statistics: randomized treatment comparison, masked assessment, imaging-based quantitative endpoints, and the distinction between a prespecified hypothesis and a reported statistical result.
| Concept | Application |
|---|---|
| Randomization | Creates the treatment comparison framework. |
| Masking | Reduces bias in treatment assessment. |
| Continuous outcomes | Lesion volume provides a quantitative endpoint. |
| Phase 2 design | Evaluates preliminary evidence. |