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 A Safety Extension Study in Patients With Erythropoietic Protoporphyria (EPP) (NCT04578496), a na phase 3 study. The primary outcome is Change in Quality of Life Measured Using the EPP-quality of Life Questionnaire (EPP-QoL)..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04578496 |
| Phase | Phase 3 |
| Condition | Erythropoietic Protoporphyria |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 16 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Clinuvel Pharmaceuticals Limited |
| Results posted | Yes |
2. Clinical Question
Population
Patients with erythropoietic protoporphyria (EPP) were enrolled. The registry record lists an enrollment of 16 and identifies the intent-to-treat population for the primary quality-of-life outcome. Details such as participant ages, eligibility criteria, disease severity, and demographic composition are not reported in the registry record.
Intervention
The intervention was afamelanotide, listed as a drug. The registry record describes the study as a safety extension and gives the study’s main objectives as evaluating safety and tolerability through treatment-emergent adverse events and determining whether afamelanotide can improve quality of life. Dosing and treatment-administration details are not reported in the registry record.
Comparator
There was no comparator group in the registered design. The study is listed as single-group, with allocation recorded as not applicable and no masking. Consequently, the registered data do not provide a like-for-like control comparison. Details of any earlier study associated with the extension are not reported in the registry record.
Primary question
The primary outcome concerns change in EPP-related quality of life, measured with the EPP-quality of Life Questionnaire (EPP-QoL). The registry lists measurements at baseline, Day 60, Day 120, Day 180 or early termination if applicable. It describes the outcome as a median with the full range, but a numerical result is not reported in the registry record. The main clinical question is therefore identifiable, but the magnitude and precision of any observed change cannot be assessed from the registered results.
3. Trial Design
The registry describes NCT04578496 as a Phase III safety extension study in patients with EPP. It lists Clinuvel Pharmaceuticals Limited as the sponsor, an enrollment of 16, and a completed status. The recorded start date is 2011-07-11, and the primary completion date is 2014-02-27. The registry title identifies the study as a safety extension, but details about the study that preceded it, or how participants entered the extension, are not reported in the registry record.
The registered model is single-group, allocation is not applicable, and masking is listed as none. Afamelanotide is the intervention. No control arm or randomized comparison is described. This design can describe observations among participants in the treated group, but does not provide a concurrent group for separating changes associated with treatment from changes that might occur for other reasons.
The main stated objectives were to evaluate afamelanotide safety and tolerability by measuring treatment-emergent adverse events, and to determine whether afamelanotide can improve quality of life for patients with EPP. The primary outcome is change in EPP-QoL score. Adverse-event counts are also recorded. The registry lists 2 outcome measures and 0 analyses. A detailed schedule of visits beyond the primary outcome time points, treatment duration, adherence assessment, and procedures for collecting adverse events are not reported in the registry record.
The single-group structure is important when interpreting any change over time: a before-and-after pattern in one group is not a randomized treatment contrast. No masking also means the record does not describe procedures intended to keep participants or investigators unaware of treatment assignment. Further details of conduct, including any protocol changes, 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
| Stage | Afamelanotide |
|---|---|
| STARTED | 16 |
| COMPLETED | 12 |
| NOT COMPLETED | 4 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-treat population
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 | Afamelanotide |
|---|---|---|
| Participants analysed | 16 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 15 |
| Age, Categorical: >=65 years | Participants | 1 |
| Sex: Female, Male: Female | Participants | 11 |
| Sex: Female, Male: Male | Participants | 5 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Quality of Life Measured Using the EPP-quality of Life Questionnaire (EPP-QoL)., measured over Baseline, Day 60, Day 120, Day 180 or early termination (ET) (if applicable).
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | EPP-QoL score |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is change in quality of life measured with the EPP-quality of Life Questionnaire (EPP-QoL). The registry describes it as 15 questions about how EPP has affected the patient over the last 2 months. Each question uses a categorical response scale. The total score is described as ranging from a minimum of 0 to a maximum of 100, with higher scores indicating better quality of life.
The listed assessment times are baseline, Day 60, Day 120, Day 180 or early termination if applicable. The registry specifies a median and full range as the summary format and identifies the intent-to-treat population. It does not provide the actual median scores, ranges, or changes at those times. Thus, the direction and size of any observed quality-of-life change cannot be read from the registry record.
In general, a patient-reported quality-of-life measure can capture effects of illness that are not represented by clinical events alone. Repeated assessments can describe how reported quality of life varies over the study period. In a single-group study, however, those observations do not by themselves establish that a change was caused by the intervention. How the score was handled when a participant missed an assessment is not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registered results permit a limited descriptive reading. For serious adverse events, the afamelanotide group lists 0 affected participants among 16 at risk. For the other adverse-event category, it lists 1 affected participant among 16 at risk. The registry does not list serious adverse-event terms, and deaths are not reported in the registry record. These counts describe the entries recorded for this study; they do not provide a detailed account of event types, timing, severity, or relationships to treatment.
The primary outcome is well described in terms of the instrument, score direction, summary format, population, and planned assessment times. However, a numerical EPP-QoL result is not reported in the registry record. There is therefore no registered estimate of change to interpret, and no reported range with which to judge variability among participants. The registry lists 0 analyses, so no inferential result, confidence interval, or hypothesis test is available for the primary outcome in the record.
The study is single-group and has no masking. In general, a change between baseline and later assessments can reflect multiple influences, including the natural course of a condition, expectations, changes in care, or measurement variation. Without a concurrent control group, the registered design cannot distinguish these possible influences from an intervention-associated change. This is a design limitation, not a claim about what caused any individual participant’s experience.
Counts of adverse events also require careful framing. The number of participants recorded as affected is not the same as a complete description of event burden: the registry record does not give event counts by type or the timing and duration of events. The absence of listed serious adverse-event terms does not supply those details. Likewise, the reported counts should not be treated as a comparison with another treatment or with an untreated group, since no such comparator is registered.
Any sample-size figures associated with planning are illustrations rather than observations from this trial or evidence of observed power. The stated planning assumptions refer to a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the target effect defined as a fraction of the observed effect. Those assumptions do not describe the registered single-group design. The registry record does not report a primary endpoint effect estimate that could be used to assess such planning illustrations. Overall, the record supports describing the design and the adverse-event counts, but not judging the size, precision, or cause of a quality-of-life change.
9. Statistical Methods Explained
Statistical methods determine how observations are summarized and how uncertainty is assessed. The registry record identifies the primary outcome summary as a median with the full range, but does not report a statistical analysis plan or any analyses. The explanations below describe the concepts relevant to the registered design; they should not be read as methods confirmed to have been used in this study.
Why report a median and full range?
In general, the median is the middle value when observations are ordered. It describes the center of a set of scores without being pulled as strongly as the mean by unusually high or low observations. The full range gives the lowest and highest observed values, showing the overall spread but not how densely observations cluster between the endpoints. These summaries can be useful for a bounded questionnaire score, especially when the distribution is not well described by a symmetric model. The registry specifies these summaries but does not report the median or range at any assessment time.
A median at each time point would describe the group at that time; it would not, by itself, quantify the median within-person change. To evaluate change, the analysis must define how paired observations are handled and which participants contribute to each comparison. Such details, including whether the reported change is calculated from individual changes or from group summaries, are not reported in the registry record. No additional calculation can be inferred from the listed summary format alone.
What does a confidence interval represent?
In general, a confidence interval gives a range of values compatible with an estimate under the assumptions of the statistical method. Its width reflects precision: a narrower interval indicates less sampling uncertainty under those assumptions, while a wider interval indicates more. An interval does not correct for bias, missing outcomes, or limitations in the study design. The registry record does not report a confidence interval for the EPP-QoL outcome or an analysis from which one could be interpreted.
A hypothesis test and a confidence interval answer related but distinct questions. A test evaluates how compatible the data are with a specified null hypothesis, while an interval displays a range of plausible values for an effect estimate. Neither can establish causation in a single-group design simply by reaching a statistical threshold. No primary-outcome test or estimate is reported in the registry record.
Why does the single-group design matter?
For a randomized comparison, an outcome contrast between groups can help estimate the difference associated with assigned interventions, subject to the quality of conduct and analysis. This study is registered as single-group, with allocation not applicable and no masking. It therefore has no concurrent control-arm contrast. A change from baseline may be described, but other time-related influences and measurement effects cannot be separated from an intervention-associated change using a control comparison that the record does not contain.
In general, masking can reduce some ways that knowledge of treatment assignment influences expectations, care, reporting, or outcome assessment. The registry lists masking as none. The record does not describe whether any other procedures were used to reduce such influences. It also does not report a model for repeated measurements, adjustment for baseline characteristics, or an approach to within-participant correlation. Those analysis choices cannot be assumed.
What do the planning assumptions mean?
The stated sample-size assumptions describe a planning illustration: a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target is described as a stated fraction of an observed effect. These are planning assumptions, not a description of the registered study, which has a single group and no randomized comparator. Sample-size illustrations are not observed power and do not indicate what the trial actually demonstrated. No specific planning figure or primary endpoint effect estimate is reported in the registry record, so the numerical implications cannot be assessed from this record.
In general, a planned sample size depends on assumptions about the effect to detect, outcome variability, the significance threshold, and the statistical test. If the true effect or variability differs from the assumptions, the operating characteristics can differ from the plan. A planning calculation cannot substitute for a reported estimate and its uncertainty, and it cannot repair the absence of a control group.
What is not established by the registry record?
The record does not report the primary endpoint’s numerical results, inferential analyses, confidence intervals, missing-data methods, or a detailed analysis plan. It does not specify whether any interim analyses were planned or conducted. In general, those details matter because readers need to know which observations entered each analysis, how incomplete follow-up was treated, and whether the analysis followed a prespecified approach. Without those details, interpretation should remain descriptive and limited to the outcomes and counts that are actually registered.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 2 outcome measures, but provides no analyses. It identifies EPP-QoL change as the primary outcome and describes safety and tolerability as main objectives. The full details of any additional outcome, the hierarchy among outcomes, and any prespecified testing strategy are not reported in the registry record.
Multiplicity arises when several outcomes, time points, or comparisons are tested. In general, conducting many tests can increase the chance of a seemingly notable result arising by chance, so a statistical plan may specify which results are confirmatory and whether adjustment is needed. The record does not describe any multiplicity adjustment, testing hierarchy, or planned handling of repeated assessments. Because no inferential results are reported, the impact of multiplicity on any conclusion cannot be evaluated.
The primary outcome lists baseline, Day 60, Day 120, Day 180 or early termination if applicable. The record does not state how missing questionnaire responses, missed visits, early termination, or incomplete follow-up were handled. It also does not report the number contributing EPP-QoL data at each time point. The intent-to-treat population is named, but its operational definition and the specific participants included in the primary analysis are not reported in the registry record.
In general, missing outcomes can affect both precision and the meaning of an estimate, particularly if the probability of missingness relates to a participant’s health or experience. Different assumptions and methods for incomplete data can lead to different interpretations. No imputation method, sensitivity analysis, or missing-data assumption is reported in the registry record. The adverse-event denominators are recorded as 16 at risk for each listed category, but this does not establish how missing follow-up was handled for the quality-of-life endpoint.
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 |
|---|---|---|---|
| Afamelanotide | 0 | 16 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Afamelanotide | 1 of 16 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Afamelanotide |
|---|---|---|
| Headache | Nervous system disorders | 1 of 16 |
The serious adverse-event entry lists 0 affected participants among 16 at risk in the afamelanotide group. The other adverse-event entry lists 1 affected participant among 16 at risk. The registry record lists no serious adverse-event terms. Deaths are not reported in the registry record.
These are participant counts in the registered categories, not a complete narrative of individual events. The record does not report event names for the other adverse-event category, the number of events per participant, onset or duration, severity details beyond the serious-event grouping, or the assessment of relationship to afamelanotide. It also does not give a comparator group, so the counts cannot be read as a relative safety comparison.
In general, adverse-event counts are descriptive: they indicate how many participants were recorded as affected under the reported category, but do not by themselves explain why an event occurred. A count of 0 serious adverse events in this group should not be interpreted as evidence that serious events are impossible or that risk is absent. The amount and detail of follow-up needed for a broader safety assessment are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The registry record identifies a focused clinical question: quality-of-life change among patients with EPP receiving afamelanotide in a safety extension study, alongside assessment of treatment-emergent adverse events. It describes the EPP-QoL instrument and the intended assessment times, and records adverse-event counts for the single intervention group. These details make the study’s stated aims and some aspects of its measurement approach clear.
The record does not report numerical EPP-QoL results, a primary endpoint estimate, or statistical analyses. It therefore does not establish the size or precision of any quality-of-life change. The adverse-event counts are limited descriptive information and do not include event terms or a control comparison. The registered information does not support a conclusion about whether a change was caused by afamelanotide.
In general, results from a single group can describe what was observed among participants, but they do not provide the same causal contrast as a randomized comparison. Changes over time may have several explanations, and the registry record does not report an analysis that separates them. The absence of a reported primary endpoint result is also distinct from a finding of no change: without the numerical result, neither the direction nor the magnitude of change can be assessed.
The findings should therefore be read as a limited registry account of a completed study, not as a full statistical report. More detailed outcome results, participant flow, missing-data handling, and analysis methods are not reported in the registry record. This distinction is important: a stated objective, an outcome definition, and an observed result are different kinds of information, and the record supplies the first two more fully than the third.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the difference between a clearly stated outcome and a reported result. The registry specifies a patient-reported quality-of-life instrument, its scoring direction, the summary format, and intended time points. Yet it does not report the numerical outcome values or any analysis. Readers can identify what was meant to be measured, but cannot assess the observed pattern or its precision.
The design also highlights why the comparison structure matters. A single-group extension can contribute descriptive observations about participants followed during the study, and the registry records adverse-event counts. But without a concurrent comparator, changes cannot be interpreted as a controlled treatment effect. This is especially relevant for outcomes measured repeatedly over time, where time itself and other influences may affect scores.
The safety entries illustrate the limits of sparse adverse-event summaries. The record distinguishes serious from other adverse events and gives participant counts at risk, but does not provide event terms or details about timing and severity. Such counts are useful for a basic description, while a fuller safety interpretation requires information not reported in the registry record.
Finally, planning assumptions should not be confused with evidence from the study. The stated sample-size approach refers to a two-arm, equal-allocation illustration, whereas the registered trial is single-group. Planning figures can show how assumptions relate to a hypothetical design, but are not observed power and cannot replace results. Together, these features make the record a useful illustration of why study design, outcome reporting, and analysis transparency must be considered separately.
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 most direct limitation for interpretation is that the registry record does not report a numerical result for the primary EPP-QoL outcome. Although the instrument, scoring direction, summary format, and assessment times are described, there is no median, full range, estimate of change, or measure of uncertainty to evaluate. The record also lists 0 analyses.
The registered single-group design has no concurrent control, and masking is listed as none. In general, these design features limit the ability to attribute changes over time to the intervention rather than to other influences. The record does not describe other measures that might address these issues. It also does not report treatment dose, adherence, detailed eligibility criteria, participant characteristics, or details about the earlier study associated with the extension.
For the primary outcome, the registry names the intent-to-treat population but does not report the number assessed at each time point or define how that population was formed. Methods for missing questionnaire data and early termination are not reported in the registry record, although early termination is included as a possible assessment time. The effects of incomplete follow-up therefore cannot be assessed.
Safety information is limited to participant counts in the serious and other adverse-event categories. Serious event terms are not listed, and deaths are not reported in the registry record. The event types, timing, severity details, and relationship assessments are also not reported. Finally, no inferential analysis, confidence interval, multiplicity approach, or detailed statistical plan is reported. These gaps restrict the conclusions to the design description and the limited counts recorded, rather than a full evaluation of efficacy or safety.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Safety Extension Study in Patients With Erythropoietic Protoporphyria (EPP) — NCT04578496.
- Registry record last updated 2020-11-19; status last verified 2020-11.
- Results first posted 2020-11-02.
- 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
NCT04578496 is a completed Phase III, single-group safety extension study of afamelanotide in patients with EPP, sponsored by Clinuvel Pharmaceuticals Limited. The registry lists enrollment of 16, a start date of 2011-07-11, and a primary completion date of 2014-02-27. Allocation is not applicable and masking is none.
The primary outcome is change in EPP-QoL score, summarized as a median with the full range, in the intent-to-treat population. Assessments are listed at baseline, Day 60, Day 120, Day 180 or early termination if applicable. Numerical primary outcome results and analyses are not reported in the registry record. Serious adverse events are recorded for 0 of 16 participants at risk, and other adverse events for 1 of 16 at risk. Serious-event terms are not listed, and deaths are not reported in the registry record.