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 Study to Evaluate the Safety and Tolerability of Fentanyl Iontophoretic Transdermal System (Fentanyl-ITS) in the Management of Post-Surgery Pain (NCT01804673), a na phase 4 study. The primary outcome is Percentage of Participants With Global Assessment of Pain at Hour 24.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01804673 |
| Phase | Phase 4 |
| Condition | Postoperative Pain |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 174 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Janssen-Cilag G.m.b.H |
| Results posted | Yes |
2. Clinical Question
Population
Hospitalized patients with acute moderate to severe pain after surgery. The primary endpoint’s analysis population included participants who received study treatment at least once and had efficacy data after the baseline visit.
Intervention
Fentanyl iontophoretic transdermal system, identified in the registry as Fentanyl-ITS. The study was intended to assess its safety and tolerability in daily clinical practice.
Comparator
There was no comparator group in the registered design. The study is classified as a single-group study, and allocation is recorded as not applicable.
Primary question
At hour 24, what percentage of participants rated their overall pain therapy as good or excellent? The endpoint definition is recorded, but the percentage and its confidence interval are not reported in the registry record.
The clinical question is descriptive rather than a comparison between treatments. Participants rated their overall assessment of pain therapy using a four-point verbal scale: poor, fair, good, or excellent. A rating of good or excellent counted as a response; poor or fair counted as no response. Thus, the primary endpoint represents the proportion meeting that prespecified response definition at hour 24, not a change in pain intensity or a direct comparison with another treatment.
The registry also describes secondary outcomes concerning pain ratings at later time points, time with pain intensity at or below a specified level, time out of bed, mobilization, global assessments by participants, physicians and nursing staff, and ability to undergo physiotherapy or mobilization. These outcomes broaden the intended description of treatment experience and activity during hospital care. Their numerical results are not reported in the registry record. The study’s stated purpose also included the comprehensibility and usefulness of accompanying information material; no result for that purpose is reported in the registry record.
3. Trial Design
This is a phase 4, single-group study of Fentanyl-ITS in the management of post-surgery pain. The registered enrollment is 174. The study has no registered comparator arm, and allocation is listed as not applicable. Masking is recorded as none, so the design does not describe blinded assessment or treatment assignment. These design features mean the registry describes outcomes among participants receiving the study treatment, rather than a randomized between-group contrast.
The registry identifies postoperative pain as the condition and describes the setting as hospitalized patients with acute moderate to severe post-surgery pain. Its primary endpoint is assessed at hour 24 and uses participants’ global assessment of pain therapy. The stated efficacy analysis set includes participants who received study treatment at least once and had efficacy data for the primary parameter after the baseline visit. The registered enrollment should not be assumed to be the size of that endpoint analysis set: the number with qualifying treatment exposure and endpoint data is not reported in the registry record.
The study began in 2008-03, with primary completion recorded as 2008-09. Its status is terminated. The registry identifies Janssen-Cilag G.m.b.H as sponsor. The rationale for termination is not reported in the registry record, so the status alone does not establish why the study ended or what happened to its planned follow-up.
The record lists 13 outcome measures and no analyses. It names several secondary outcomes, but numerical results and analysis details are not reported in the registry record. The protocol’s statistical plan, including any planned interim monitoring, sample-size justification, and approach to analysis beyond the stated primary analysis population, is not reported in the registry record. The registered design therefore supports a descriptive reading of the intended single-group assessment, not an estimate of comparative treatment effects.
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 | Fentanyl |
|---|---|
| STARTED | 174 |
| Completed Hour 24 | 170 |
| Completed Hour 48 | 79 |
| Completed Hour 72 | 36 |
| COMPLETED | 34 |
| NOT COMPLETED | 140 |
Reasons for not completing this period:
| Reason | Fentanyl |
|---|---|
| Adverse Event | 4 |
| Withdrawal by Subject | 1 |
| Lack of Efficacy | 9 |
| Change to Oral Therapy | 37 |
| No Further Therapy Required | 84 |
| Use of Prohibited Medication | 1 |
| Other | 4 |
Analysis population for the primary outcome, as defined in the registry: Efficacy analysis set included all participants who received the study treatment at least once and who had efficacy data for the primary parameter after the 0 hour Baseline visit.
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 | Fentanyl |
|---|---|---|
| Participants analysed | 174 | |
| Age Continuous | Years | 49.3 (SD 16.7) |
| Sex: Female, Male: Female | Participants | 86 |
| Sex: Female, Male: Male | Participants | 88 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Participants With Global Assessment of Pain at Hour 24, measured over Hour 24.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | 95% Confidence Interval |
| Unit | percent of participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of participants with a global assessment of pain therapy rated good or excellent at hour 24. Participants used a four-point verbal rating scale: poor, fair, good, or excellent. The endpoint combines the two more favorable categories as a response and the other two categories as no response. It is therefore a binary summary of a participant’s overall judgment at a specified time, rather than a measure of the magnitude of pain or change from baseline.
A percentage can make the frequency of a defined response easier to interpret than a list of individual ratings. Its confidence interval is intended to communicate the statistical uncertainty around the estimated percentage: a narrower interval indicates greater precision, while a wider interval indicates less precision. The registry names a 95% confidence interval as the endpoint’s dispersion measure, but neither the percentage nor the interval is reported in the registry record. Consequently, the magnitude and precision of the primary endpoint cannot be assessed from this record.
The endpoint is based on participant global assessment, which captures an overall impression of pain therapy rather than a clinician-rated judgment alone. It is measured at hour 24, so it describes a particular time point and does not by itself characterize ratings at later times. The registry lists separate outcomes for later global assessments and other aspects of pain and activity. Those outcomes should not be substituted for the primary endpoint, and their results are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry provides a clear definition of the primary outcome but does not report its observed percentage or 95% confidence interval. Without those values, the primary endpoint cannot be interpreted quantitatively: the rate of good or excellent ratings, and the uncertainty around that rate, are not reported in the registry record. The endpoint’s definition alone does not establish what participants reported.
Even if a single-group response percentage were available, it would describe the observed responses among eligible participants in this study. With no comparator group and no randomized allocation, it would not estimate a treatment difference relative to another therapy or to no treatment. Changes over time, clinical context, patient selection, and other influences could not be separated from the treatment experience through a between-group contrast in this design. This is a general limitation of interpreting single-group outcomes, not a finding about the participants’ results.
The primary analysis population is described as participants who received study treatment at least once and had efficacy data after baseline. That definition matters because the enrolled group and the group contributing to the endpoint may differ. The registry does not report the size of the endpoint analysis population, the number with missing hour 24 ratings, or the missing-data method. The extent to which the reported endpoint, if available elsewhere, would represent all enrolled participants therefore cannot be determined from the registry record.
The endpoint’s 95% confidence interval would describe sampling uncertainty under the analysis used; it would not account automatically for biases arising from selection, missing responses, measurement, or the absence of a comparator. General statistical interpretation distinguishes precision from validity: a precise estimate can still be limited by the design or by how the data were collected. Here, neither the estimate nor its interval is reported, so even precision cannot be evaluated.
Several secondary outcomes are listed, including pain intensity, time with lower average pain intensity, time out of bed, mobilization, global assessments at later times, and assessments by clinicians and nursing staff. Their definitions indicate a range of intended measurements, but no numerical secondary results are reported in the registry record. The record lists 13 outcome measures and no analyses; it does not explain how the outcomes were prioritized or how any multiple testing was handled.
The safety record reports 3 participants affected by serious adverse events and 86 affected by other adverse events, with 174 at risk recorded for each category. These figures describe safety reporting in the registry and should not be read as a comparative risk estimate. The record does not report a comparator group, and it does not provide the information needed to determine whether events were caused by treatment. The death count is not reported in the registry record. The listed serious event terms each have a recorded value of 0.6%; the record does not establish whether those terms overlap within participants.
Overall, the record supports conclusions about study structure, endpoint definition, and the presence of recorded safety counts. It does not support a numerical conclusion about the primary response rate, its precision, secondary outcomes, or comparative benefit and harm. The reason for termination and the study’s detailed statistical plan are not reported in the registry record.
9. Statistical Methods Explained
Statistical methods help distinguish what an outcome measures from how precisely it is estimated and what comparisons the design can support. In this record, the primary endpoint is a binary response: a participant’s hour 24 global assessment is classified as response if rated good or excellent, and as no response if rated poor or fair. The target summary is the percentage of participants classified as responders in the defined efficacy analysis set.
What does a percentage estimate?
For a binary outcome, the percentage describes the fraction of participants in an analysis population who meet a stated category. It is not a measure of the average rating, and it does not preserve the distinction between good and excellent or between poor and fair once the categories are combined. This simplification can make the endpoint easy to communicate, but it also means that the endpoint does not show the full distribution of ratings.
The registry identifies the primary endpoint’s dispersion measure as a 95% confidence interval. In general, a confidence interval gives a range of values compatible with the data and the statistical method used, while reflecting sampling uncertainty. It does not guarantee that the true value lies within the interval, and it does not include every source of uncertainty. For example, it does not automatically correct for missing data, selection effects, or limitations of a single-group design. The endpoint estimate and interval are not reported in the registry record, so their numerical interpretation is unavailable.
What can a single-group design estimate?
A single-group study can describe outcomes observed among participants in that group. Without a comparator, it cannot directly estimate a difference between Fentanyl-ITS and another treatment. A result from one group could be influenced by factors other than the treatment, such as the circumstances of enrollment, clinical care, or changes over time. These are general considerations for interpreting noncomparative studies, rather than claims about what occurred in this study.
Allocation is recorded as not applicable and the model as single group. Masking is recorded as none. There is consequently no registered randomized treatment contrast to interpret. The absence of masking can also matter for subjective assessments: participant and assessor expectations may influence reported or observed judgments in general. The registry record does not describe additional procedures intended to reduce such influence.
Why does the analysis population matter?
The primary endpoint population is defined as participants who received the study treatment at least once and had efficacy data for the primary parameter after the baseline visit. This definition specifies who qualifies for that endpoint analysis. It is not necessarily identical to the registered enrollment, because treatment exposure and available endpoint data are part of the definition. The number included in the primary analysis is not reported in the registry record.
Missing outcome data can affect an estimated percentage if participants with unavailable ratings differ from those with observed ratings. Statistical approaches to missing data make assumptions about the unavailable values and about the process that made them unavailable. The registry does not report the number missing at hour 24 or the method, if any, used to address missing values. No particular missing-data assumption should therefore be attributed to this study.
How should planning illustrations be read?
General sample-size calculations ask how many participants might be needed to detect a specified effect under stated assumptions. The planning illustration associated with this study uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; its target effect is a stated fraction of the observed effect. These assumptions describe a planning exercise, not the registered single-group study design. In particular, the two-arm equal-allocation assumption does not turn this trial into a comparative trial.
A planning sample size is not an observed sample size and is not evidence that a study had a particular probability of detecting an effect after the fact. Such calculations depend on the effect selected for planning and on other assumptions. The observed primary effect is not reported in the registry record, and no numerical planning estimates are reported in the registry record. The protocol’s own sample-size justification is not reported in the registry record. These planning concepts should not be interpreted as a retrospective measure of study success or as an account of the original design rationale.
What do multiple outcomes imply?
The registry lists 13 outcome measures, including the primary endpoint and multiple secondary outcomes, and lists no analyses. When many outcomes or time points are examined, the chance of at least one apparently notable finding can increase if each is tested separately. General statistical practice may address this through a prespecified hierarchy, adjusted thresholds, or descriptive reporting, depending on the study’s purpose. The registry does not report a multiplicity procedure, so none can be assumed. Since numerical outcome results are not reported, the record also does not permit assessment of how findings across outcomes relate to one another.
Overall, the available methods information defines the primary measure, the endpoint time, the response categories, and the efficacy analysis population. It does not provide the numerical endpoint estimate, the confidence interval, the missing-data approach, or a full statistical analysis plan. A careful statistical interpretation should keep those distinctions explicit.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 13 outcome measures and identifies a primary endpoint at hour 24 alongside secondary outcomes addressing pain intensity, activity, mobilization, and global assessments at other times or by other assessors. Multiple outcomes can raise a multiplicity concern when several statistical tests are used to support conclusions: the chance of at least one apparently positive result can rise as more tests are considered. General approaches include prespecifying a hierarchy, adjusting inference, or treating secondary outcomes as descriptive. The registry record does not report which approach, if any, was planned. It lists no analyses, and no outcome results are reported in the registry record.
The primary efficacy population includes participants who received treatment at least once and had efficacy data after baseline. This is a stated eligibility definition, not a count of analyzed participants. The registry does not report the number with hour 24 data, the number missing, or how missing values were handled. It also does not report whether analyses used any other populations or sensitivity analyses. Missingness can affect a response percentage if people without recorded outcomes differ from those with recorded outcomes; how much it matters depends on the pattern and handling of missing data, neither of which is reported.
The record’s lack of an analysis description should not be taken to mean that no statistical work occurred outside the registry record. It means the registry does not report an analysis plan or results that would allow readers to evaluate multiplicity, missing-data assumptions, or consistency across analysis populations. These gaps limit interpretation of both the primary endpoint and the wider set of registered outcomes.
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 |
|---|---|---|---|
| Fentanyl | 3 | 174 | 1.7% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 1% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Fentanyl | 86 of 174 |
Most frequent serious adverse event terms
| Event term | Organ system | Fentanyl |
|---|---|---|
| Hypoventilation | Respiratory, thoracic and mediastinal disorders | 1 of 174 |
| Intra-abdominal haematoma | Gastrointestinal disorders | 1 of 174 |
| Impaired healing | General disorders | 1 of 174 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Fentanyl |
|---|---|---|
| Nausea | Gastrointestinal disorders | 27 of 174 |
| Application site erythema | General disorders | 18 of 174 |
| Vomiting | Gastrointestinal disorders | 16 of 174 |
| Dizziness | Nervous system disorders | 6 of 174 |
| Hypotension | Vascular disorders | 6 of 174 |
| Application site vesicles | General disorders | 5 of 174 |
| Erythema | Skin and subcutaneous tissue disorders | 5 of 174 |
| Application site burn | General disorders | 4 of 174 |
| Procedural nausea | Injury, poisoning and procedural complications | 4 of 174 |
| Procedural vomiting | Injury, poisoning and procedural complications | 4 of 174 |
Serious events with the highest arm-level rate: hypoventilation (0.6%), intra-abdominal haematoma (0.6%), impaired healing (0.6%).
The registry reports 3 participants affected by serious adverse events and 86 affected by other adverse events. For each category, 174 is recorded as at risk. These are safety counts, not estimates of treatment effects against a control group. The registry does not describe a comparator arm, and the figures alone do not establish whether an event was caused by Fentanyl-ITS.
Hypoventilation, intra-abdominal haematoma, and impaired healing are listed among the serious adverse event terms, each with a recorded value of 0.6%. The registry record does not clarify whether a participant could contribute to more than one term, so the terms should not be added or treated as mutually exclusive categories. The death count is not reported in the registry record.
In general, adverse-event counts depend on how events were defined, collected, and classified, as well as the period of observation. Those details are not reported in the registry record. The counts describe what is recorded, but they do not provide a comparative safety estimate or a complete account of event timing, severity beyond the serious classification, or causal attribution.
12. What the Result Does, and Does Not, Mean
The record documents a phase 4, single-group study intended to evaluate safety and tolerability of Fentanyl-ITS in daily clinical practice for acute moderate to severe post-surgery pain in hospitalized patients. It defines a primary endpoint based on participant global assessment at hour 24 and specifies which ratings count as response. It also records adverse-event counts and lists several other outcome measures. These are meaningful details about what the study set out to assess and what the registry records.
The primary endpoint’s result is not reported in the registry record. Neither the percentage classified as good or excellent nor its 95% confidence interval is available. As a result, the record does not establish the observed response rate or how precisely it was estimated. Secondary outcome results are also not reported. The endpoint definition must not be mistaken for an endpoint finding.
Because the study is single group and has no registered comparator, its design does not provide a direct estimate of how outcomes would differ under another treatment. This general design limitation applies even if an outcome percentage is available from another source. The registry record also does not report the reason for termination, a detailed analysis plan, or the handling of missing outcomes, limiting assessment of the study’s conduct and interpretation.
The safety counts indicate that adverse events were recorded, including serious adverse events. They do not by themselves establish treatment causality, comparative risk, or the full clinical context of each event. The listed serious event terms and their percentages should be read as descriptive entries, not as a comparison or a complete event profile.
Accordingly, the record can be used to understand the study question, design, endpoint definition, analysis-population criteria, and selected safety information. It cannot support a quantitative conclusion about the primary response outcome or comparative effectiveness. It also cannot resolve uncertainty about missing data, the statistical plan, or why the study was terminated. Those limits are central to interpreting the registered information.
13. Why This Trial Matters Statistically
This study is statistically notable as a single-group, phase 4 evaluation with a participant-reported primary endpoint and no registered comparator. It illustrates the difference between defining an outcome and reporting its estimate. The registry specifies how the hour 24 rating becomes a binary response, but without the percentage and confidence interval readers cannot judge the observed response frequency or its precision.
The design also highlights the distinction between descriptive evidence and comparative evidence. A single-group study can record participant assessments and safety events in a clinical setting, but it does not isolate a treatment contrast against another group. This is a general interpretation issue rather than a statement about the direction of any unreported outcome.
The analysis-population definition is another important statistical detail. Requiring treatment exposure and post-baseline efficacy data identifies who was eligible for the primary analysis, but the number analyzed and the amount of missing data are not reported. Those details would help readers understand how much the endpoint reflects the enrolled population and how sensitive it might be to unavailable ratings.
Finally, the record lists many outcome measures but no analyses. Without reported results or a multiplicity plan, readers cannot assess whether outcomes were analyzed as a prespecified hierarchy, how secondary findings relate to the primary question, or how uncertainty was managed across endpoints. These are broadly relevant issues when interpreting registry records: study design, outcome definition, analysis population, missingness, and reporting all shape what a numerical result could mean.
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 primary limitation for interpretation is that the registry defines the hour 24 primary endpoint but does not report its result or 95% confidence interval. The registered enrollment is 174, but the number meeting the primary analysis-set definition is not reported. The record therefore does not show either the endpoint’s observed response proportion or the precision of that estimate.
The single-group design has no registered control comparison. Masking is recorded as none, and allocation is not applicable. As a result, any descriptive outcome could not by itself distinguish treatment-associated changes from other influences. This is a design limitation, not evidence that any particular influence occurred.
The registry does not report the number of missing primary endpoint observations, the method for handling missing data, or sensitivity analyses. It does not report a multiplicity procedure despite listing 13 outcome measures, and it lists no analyses. Results for the secondary outcomes are not reported in the registry record.
The status is terminated, but the reason for termination is not reported in the registry record. The duration and completeness of safety observation, event definitions, event timing, and causal assessments are also not reported. The death count is not reported in the registry record. These gaps mean that the recorded safety counts should be treated as limited descriptive information, not as a complete safety assessment or a comparative risk estimate.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study to Evaluate the Safety and Tolerability of Fentanyl Iontophoretic Transdermal System (Fentanyl-ITS) in the Management of Post-Surgery Pain — NCT01804673.
- Registry record last updated 2013-08-05; status last verified 2013-08.
- Results first posted 2013-08-05.
- 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
The registry describes a phase 4, single-group study of Fentanyl-ITS for post-surgery pain in hospitalized patients. Enrollment is recorded as 174; masking is none, and allocation is not applicable. The study began in 2008-03, primary completion is recorded as 2008-09, and status is terminated.
The primary endpoint is the percentage of participants rating pain therapy good or excellent at hour 24, with a 95% confidence interval specified. The endpoint result, interval, secondary outcome results, and detailed statistical plan are not reported in the registry record. The efficacy population is defined by treatment exposure and post-baseline efficacy data, but its size is not reported.
The safety record lists 3 participants affected by serious adverse events and 86 affected by other adverse events, with 174 at risk recorded for each category. Three serious event terms are listed at 0.6% each. The death count and reason for termination are not reported in the registry record.