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 Afamelanotide as Adjunctive Therapy in Patients Undergoing Photodynamic Therapy (PDT) Utilising Porfimer Sodium (NCT04425746), a randomized phase 2 study. The primary outcome is The First Day on Which Patients Are Free From Symptoms of Phototoxicity Following Phototesting.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04425746 |
| Phase | Phase 2 |
| Condition | Patients Undergoing Photodynamic Therapy Using Porfimer Sodium |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 16 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Clinuvel Pharmaceuticals Limited |
| Results posted | Yes |
2. Clinical Question
Population
Patients undergoing photodynamic therapy using porfimer sodium. The registry record lists enrollment as 16 and describes clinic visits and phototoxicity assessments.
Intervention
Afamelanotide, described in the study materials as CUV1647, administered as an implant alongside porfimer sodium.
Comparator
A placebo implant alongside porfimer sodium. The registry record describes both groups as following the same planned visit schedule.
Primary question
Whether the time until patients were free of symptoms or reactions of phototoxicity following phototesting could be evaluated when afamelanotide was used as an adjunct to photodynamic therapy.
The study was designed to assess safety and efficacy in patients undergoing photodynamic therapy using porfimer sodium. The primary endpoint concerned the first day on which patients were free from symptoms of phototoxicity following phototesting, with the stated timeframe from Day 04 to Day 90. The record also describes the planned efficacy measure as the number of days free of phototoxic reactions following phototesting.
That question could not be answered from the planned diary-based efficacy measure: the registry record says patients did not complete the diaries appropriately, so the data could not be collected. The registry record does not report a treatment-effect estimate for this endpoint. A secondary outcome was change in quality of life, but an estimate or result for that outcome is not reported in the registry record. Thus, the clinical question describes the study's aim, not an efficacy conclusion established by the posted results.
3. Trial Design
This was a Phase II, randomized, parallel-group, placebo-controlled pilot study. The official title describes it as multicentre and double-blind. The registry record lists quadruple masking; it does not report which roles were masked. Allocation was randomized, and the two interventions were afamelanotide and placebo. Both groups received porfimer sodium as part of the planned photodynamic therapy regimen.
The registry lists enrollment as 16. That is the stated study enrollment, not a treatment-effect estimate. The record describes a common visit plan: Day 0 for implant administration and porfimer sodium, Day 2 for photodynamic therapy, and Days 20 and 90 for assessments. The planned assessments included adverse events, concomitant medication, and phototoxicity evaluation. The endpoint timeframe is stated as From Day 04 to Day 90.
The study status is completed. Its recorded start date is 2008-08-05, and its primary completion date is 2009-05-28. The sponsor is Clinuvel Pharmaceuticals Limited. These registry entries describe the study's design and conduct; they do not establish that an endpoint was successfully measured or that a comparative analysis was completed.
The registry record does not report the randomization sequence method, allocation concealment procedures, or the specific people covered by masking. It also does not report details of the protocol's sample-size justification or a full statistical analysis plan. Those omissions limit what can be said about implementation and planned analysis beyond the design features explicitly listed in the 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 | Placebo |
|---|---|---|
| STARTED | 9 | 7 |
| COMPLETED | 9 | 6 |
| NOT COMPLETED | 0 | 1 |
Analysis population for the primary outcome, as defined in the registry: The planned primary efficacy endpoint was the number of days for patients to be free of phototoxic reactions following phototesting. This was recorded by patients through diaries, however these diaries were not completed appropriately, thus data could not be collected. Thus, the efficacy analysis was performed using the secondary efficacy endpoint, change in quality of life as measured by SF-36.
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 | Placebo | Total |
|---|---|---|---|---|
| Participants analysed | 9 | 7 | 16 | |
| Age, Continuous | Years | 63.0 (SD 9.3) | 72.6 (SD 8.8) | 67.2 (SD 10.0) |
| Sex: Female, Male: Female | Participants | 0 | 1 | 1 |
| Sex: Female, Male: Male | Participants | 9 | 6 | 15 |
6. Primary Endpoint
The registry lists the primary outcome as The First Day on Which Patients Are Free From Symptoms of Phototoxicity Following Phototesting, measured over From Day 04 to Day 90.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “The First Day on Which Patients Are Free From Symptoms of Phototoxicity Following Phototesting.” The record describes the planned efficacy measure as the number of days patients were free of phototoxic reactions following phototesting, assessed over the timeframe From Day 04 to Day 90. Patients were expected to record this information in diaries.
As a general statistical concept, a time-based endpoint can capture how long it takes for a defined event or state to occur. It can be useful when the timing of a change matters, rather than only whether that change has occurred by a single assessment. Interpretation depends on a clear definition of the event, consistent assessment, and sufficiently complete follow-up. The registry record does not report additional operational details for identifying symptom-free status or handling diary entries.
In this study, the record says the diaries were not completed appropriately and the data could not be collected. Therefore, the endpoint's title and planned timeframe describe the intended measurement, but no treatment comparison or estimate for it is reported in the registry record. The measure cannot establish how quickly symptoms resolved or whether the groups differed. The record lists change in quality of life as a secondary outcome, but does not report a result for it.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive issue is that the registry record does not report a usable result for the planned primary efficacy endpoint. The intended measure depended on patient diaries documenting days free from phototoxic reactions after phototesting. The record says those diaries were not completed appropriately and the data could not be collected. Without the endpoint data, the posted results cannot quantify the timing of symptom freedom or compare the afamelanotide and placebo groups on that outcome.
This is different from a finding of no difference. A missing or unmeasurable endpoint does not establish that the treatments had identical outcomes, and it does not show that either treatment changed phototoxicity. It means the planned efficacy question is unanswered by the reported primary endpoint. No confidence interval, p-value, or treatment-effect estimate for that endpoint is reported in the registry record.
The study is described as a randomized, placebo-controlled Phase II pilot study, with enrollment listed as 16. Randomization is a design feature intended to support fair comparisons, but it cannot recover outcome information that was not collected. The registry record does not report a completed efficacy analysis or analysis populations. It lists zero analyses. The record also does not report whether an alternative efficacy measure was used after the diary data could not be collected.
Safety information is reported separately from the efficacy endpoint. The registry lists serious adverse events affecting 2 participants in the afamelanotide group and 3 in the placebo group, among 9 and 7 participants at risk, respectively. It lists other adverse events affecting 6 participants in the afamelanotide group and 1 in the placebo group, with the same group-specific at-risk counts. These are descriptive registry figures; they are not a comparative estimate of treatment effect. The record does not provide a statistical analysis of the group differences, event-level context, or death counts.
General statistical interpretation requires attention to both the magnitude of an estimate and its uncertainty. A confidence interval, when reported, describes a range of values compatible with the data and analysis under its assumptions; it does not repair missing endpoint observations. No such interval is reported for the primary efficacy measure. Because the efficacy data could not be collected, the registry record does not support a precise estimate of efficacy or a conclusion about comparative benefit. The posted information is best read as documenting the study's design, the failure to collect its planned primary efficacy data, and the reported adverse-event counts.
9. Statistical Methods Explained
What does randomization contribute?
Randomization assigns participants to study groups through a chance-based process. In general, its purpose is to reduce systematic differences between groups at the outset, so that a later comparison can be more informative about the intervention. It does not guarantee that groups will be identical, particularly in a pilot study, and it does not prevent problems caused by missing outcomes, inconsistent measurement, or incomplete reporting. The registry record identifies this study as randomized, but does not report the sequence-generation or allocation-concealment methods.
What does masking mean?
Masking is intended to limit the influence of expectations on treatment delivery, participant reports, clinical assessments, or interpretation. The official title describes the study as double-blind, while the registry lists quadruple masking. The record does not specify which parties were masked or how masking was maintained. It is therefore possible to describe the registry's design labels, but not to infer the precise masking procedures or assess whether masking remained effective.
What was the endpoint intended to measure?
The primary endpoint concerned the first day patients were free from symptoms of phototoxicity after phototesting. The planned efficacy measure was described as the number of days free of phototoxic reactions, based on patient diaries, over the timeframe From Day 04 to Day 90. As a general concept, time-to-event methods address the timing of an event and can account for differing observation periods when the necessary data are available. They require an adequately defined event and information about when it occurred or whether it remained unobserved during follow-up. The registry record says the diaries were not completed appropriately and data could not be collected, so the planned efficacy endpoint cannot be interpreted through a time-to-event comparison from the posted results.
Why does missing outcome information matter?
Missing data are not simply a smaller version of complete data. General statistical methods may make assumptions about why values are missing and how missingness relates to outcomes or treatment groups. Those assumptions affect the validity of estimates. The registry record identifies diary completion as the reason the primary efficacy data could not be collected, but does not report how many diary records were incomplete, whether any usable observations remained, or whether a missing-data method was applied. No efficacy analysis is reported. Without those details, it is not possible to evaluate a statistical adjustment or infer the likely direction of any bias.
How should adverse-event counts be read?
Adverse-event summaries are descriptive unless a comparative analysis and its uncertainty are also presented. The registry gives group-specific counts of participants at risk and participants affected for serious and other adverse events. General interpretation distinguishes the number of affected participants from the number of individual events: one participant can experience more than one event, but the record's counts do not provide event-level detail. A group comparison would also need a clear definition of the analysis population, follow-up, event coding, and statistical method. Those details and an inferential comparison are not reported in the registry record.
What does a confidence interval tell a reader?
As a general statistical concept, a confidence interval expresses uncertainty around an estimated quantity under a specified method and its assumptions. A relatively wide interval signals less precision than a narrow one, although its interpretation depends on the outcome and analysis. An interval does not mean that all values inside it are equally likely, and it cannot establish that an effect is clinically important. The registry record does not report a confidence interval or an estimate for the primary efficacy endpoint. Accordingly, there is no reported interval from which to judge the precision of a primary efficacy comparison.
What is over-dispersion, and is it relevant?
General explanation: over-dispersion occurs when the observed variability in count data exceeds what a chosen statistical model expects. If a model fails to account for that extra variability, standard errors may be too small and statistical evidence may appear stronger than it is. This concept can matter when analyzing counts or rates, but the registry record does not report a count-based primary efficacy analysis or a model for such data. It is not possible to say that over-dispersion affected this study's results.
What can be said about sample-size planning?
The registry record does not report the trial's own sample-size justification. A separate planning illustration may use the observed effect as a reference and assume a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. Such an illustration is a planning exercise, not a result of the trial and not observed power. The record does not report an observed primary efficacy effect from which to assess precision, and no numeric planning estimates are stated in the registry record details.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists a primary endpoint and a secondary outcome of change in quality of life. It also states that there are two outcome measures and zero analyses. The primary efficacy measure relied on patient diaries, which were not completed appropriately; the record says the data could not be collected. It does not report a quality-of-life estimate or result, so the secondary outcome cannot be interpreted from the posted results.
Multiplicity arises when several outcomes, time points, groups, or statistical tests are examined. In general, examining more tests can increase the chance of finding an apparently notable result by chance unless the analysis plan addresses that issue. The record does not report a multiplicity adjustment, a hierarchy among outcomes beyond identifying the primary endpoint, or a complete statistical analysis plan. It is therefore not possible to assess how multiple comparisons were planned or handled.
The registry record does not report the analysis populations, the handling of missing observations, or any imputation method. It does not state whether any participants were excluded from an efficacy analysis or whether the intention-to-treat principle was applied. These are important details because analysis choices can affect how a randomized comparison is interpreted. Given the stated failure to collect the diary data and the absence of reported analyses, the primary efficacy result remains unavailable rather than statistically adjusted or conclusive.
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 | 2 | 9 | 22.2% |
| Placebo | 3 | 7 | 42.9% |
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 | 6 of 9 |
| Placebo | 1 of 7 |
Most frequent serious adverse event terms
| Event term | Organ system | Afamelanotide | Placebo |
|---|---|---|---|
| Haematemesis | Gastrointestinal disorders | 0 of 9 | 1 of 7 |
| Oesophageal stenosis | Gastrointestinal disorders | 1 of 9 | 0 of 7 |
| Overdose of Previscan (Fluindione) | Injury, poisoning and procedural complications | 1 of 9 | 0 of 7 |
| Drug toxicity (morphine) | Injury, poisoning and procedural complications | 1 of 9 | 0 of 7 |
| Subdiaphragmatic abscess | Infections and infestations | 0 of 9 | 1 of 7 |
| Thrombosis | Vascular disorders | 0 of 9 | 1 of 7 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Afamelanotide | Placebo |
|---|---|---|---|
| Headache | Nervous system disorders | 3 of 9 | 0 of 7 |
| Nausea | Gastrointestinal disorders | 2 of 9 | 0 of 7 |
| Erythema | Skin and subcutaneous tissue disorders | 1 of 9 | 1 of 7 |
| Dyspepsia | Gastrointestinal disorders | 1 of 9 | 0 of 7 |
Serious events with the highest arm-level rate: haematemesis (14.3%), subdiaphragmatic abscess (14.3%), thrombosis (14.3%), oesophageal stenosis (11.1%), overdose of previscan (fluindione) (11.1%).
The registry lists serious adverse events for the afamelanotide group as 2 affected among 9 at risk, and for the placebo group as 3 affected among 7 at risk. For other adverse events, it lists 6 affected among 9 at risk in the afamelanotide group and 1 affected among 7 at risk in the placebo group. These are participant counts in the registry record; they do not provide a treatment-effect estimate or establish that the groups differed.
The record also lists serious-event terms with percentages: Haematemesis, Subdiaphragmatic abscess, and Thrombosis at 14.3% each; Oesophageal stenosis, Overdose of Previscan (Fluindione), and Drug toxicity (morphine) at 11.1% each. The registry record does not identify these listed percentages by treatment group or report their denominators, so they should not be treated as group-specific rates. Death counts are not reported in the registry record.
As a general principle, adverse-event counts need context, including timing, severity, relationship assessments, follow-up, and whether participants experienced more than one event. Those details are not reported in the registry record. The figures are descriptive safety information, not proof that an intervention caused or prevented an event.
12. What the Result Does, and Does Not, Mean
The registry record supports a narrow account of what the study set out to do and what information was reported. It describes a randomized, parallel-group, placebo-controlled Phase II pilot study of afamelanotide as adjunctive therapy in patients undergoing photodynamic therapy using porfimer sodium. It also states that the planned diary-based primary efficacy data could not be collected because the diaries were not completed appropriately.
That outcome is a limitation of the evidence, not an efficacy result. The absence of a reported primary endpoint estimate does not mean that there was no effect, nor does it demonstrate an effect. It means the registry record does not answer the planned efficacy question. The secondary outcome, change in quality of life, is listed, but its result is not reported in the registry record.
The adverse-event counts provide descriptive information about participants listed as affected in each group. They do not, on their own, establish causation or quantify a reliable comparative safety effect. The registry does not report a statistical comparison, confidence intervals, detailed event timing, or death counts. Interpretation should therefore remain limited to the counts and terms that are explicitly recorded.
As a general statistical principle, a trial's design and its observed results answer different questions. Randomization and masking describe how a comparison was intended to be conducted; usable outcome data and an appropriate analysis are needed to estimate a treatment difference. In this record, the design is documented, but the planned primary efficacy measure is not available for analysis. The record does not report enough information to infer why diary completion failed, whether other measures could substitute for it, or how any unreported outcomes compare between groups.
The study can therefore be understood as a completed pilot trial whose primary efficacy endpoint did not yield analyzable data in the registry report. It should not be read as a positive or negative efficacy finding. Its posted safety figures are also descriptive and should not be treated as definitive comparative evidence.
13. Why This Trial Matters Statistically
This trial illustrates a basic distinction in clinical research: a well-defined question and a randomized design do not guarantee an answer if the outcome data are not successfully collected. The planned primary measure depended on participants recording symptom-free days after phototesting. The registry record states that the diaries were not completed appropriately, leaving the planned efficacy data unavailable.
That matters statistically because missing outcome data can prevent estimation of the treatment effect and its precision. Randomization can support a fair comparison when outcomes are observed, but it cannot replace the observations needed to calculate that comparison. Nor can a lack of an estimate be interpreted as evidence of no difference. This distinction is especially important when a registry record contains design details and adverse-event counts alongside no analyzable primary efficacy result.
The study also highlights the importance of practical measurement procedures. As a general research principle, participant-reported outcomes require clear instructions, feasible recording methods, and monitoring that supports complete data collection. The registry record does not describe what caused the diary problem or what measures were used to address it. It does, however, document the consequence for the planned endpoint: the data could not be collected.
Finally, this record shows why safety counts and efficacy outcomes should be interpreted separately. Descriptive adverse-event figures can inform what the registry reports, but they do not answer the primary efficacy question or establish causality. For readers assessing clinical evidence, the key statistical lesson is to distinguish a study's intended analysis from the results it could actually report.
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 main limitation specific to this study is the unavailability of the planned primary efficacy data. The endpoint depended on diaries completed by patients, and the registry record states that the diaries were not completed appropriately. As a result, data could not be collected and no efficacy analysis is reported. The record does not describe the extent of diary incompleteness, whether any observations were usable, or whether a replacement endpoint was analyzed.
The registry lists enrollment as 16, but does not report an efficacy analysis population or the number included in any endpoint analysis. It does not report a primary efficacy estimate, confidence interval, or p-value. These omissions preclude assessment of the magnitude and precision of a treatment comparison for the planned endpoint.
The record lists change in quality of life as a secondary outcome without reporting its result. It does not report a statistical analysis plan, multiplicity procedures, or the handling of missing data. The masking label differs between the official title, which says double-blind, and the registry field, which says quadruple; the specific masked parties are not reported in the registry record.
Safety reporting is also limited. Group-specific participant counts are listed for serious and other adverse events, but the record does not report event-level timing, group assignments for the listed serious-event percentages, or death counts. The available information supports descriptive reading only and does not establish causality or a comparative safety effect.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Afamelanotide as Adjunctive Therapy in Patients Undergoing Photodynamic Therapy (PDT) Utilising Porfimer Sodium — NCT04425746.
- Registry record last updated 2021-10-01; status last verified 2021-09.
- Results first posted 2021-10-01.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed, randomized, parallel-group, placebo-controlled Phase II pilot study of afamelanotide as adjunctive therapy for patients undergoing photodynamic therapy using porfimer sodium. Enrollment is listed as 16. The study compared an afamelanotide implant with a placebo implant, with porfimer sodium used in both groups.
The planned primary endpoint concerned the first day free from symptoms of phototoxicity following phototesting, assessed over From Day 04 to Day 90. The record says the patient diaries were not completed appropriately, so the efficacy data could not be collected. No primary efficacy analysis is reported. Change in quality of life is listed as a secondary outcome without a reported result.
The registry reports group-specific counts for serious and other adverse events. These are descriptive figures; the record does not report a comparative safety analysis or death counts. The posted information documents the study design and the limitation affecting its primary efficacy endpoint, but does not establish an efficacy conclusion.