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 Absorption, Metabolism, and Excretion of a Single Dose of Ferriprox® in Patients With Sickle Cell Disease (NCT01835496), a na phase 1 study. The primary outcome is Cmax for Serum Deferiprone and Deferiprone 3-O-glucuronide.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01835496 |
| Phase | Phase 1 |
| Condition | Sickle Cell Disease |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 8 |
| Arms in the primary outcome | n/a |
| Lead sponsor | ApoPharma |
| Results posted | Yes |
2. Clinical Question
Population
Patients with sickle cell disease. The registry record lists an enrollment of 8. It does not report further eligibility details or describe the characteristics of the participants who contributed to each endpoint.
Intervention
A single 1500 mg dose of Ferriprox. The study objective was to evaluate the pharmacokinetics of deferiprone and its 3-O-glucuronide metabolite following administration.
Comparator
There was no separate comparator group. The registry record describes a single-group study with allocation listed as NA and masking listed as NONE. The dose was not compared with a control treatment or another dose in the design described.
Primary question
What were the maximum measured serum concentrations, or Cmax values, for deferiprone and deferiprone 3-O-glucuronide over a 10-hour interval after dosing? The endpoint description specifies the measurement and sampling schedule, but numerical Cmax results are not reported in the registry record. The record therefore does not establish the size or precision of either concentration estimate.
In practical statistical terms, this is a descriptive pharmacokinetic question after a single dose, not a test of comparative efficacy. The record also lists adverse-event frequency and serious adverse-event frequency as secondary outcomes. It does not provide numerical results for the primary pharmacokinetic endpoint, nor does it report analyses that connect concentration measurements with adverse events. The clinical question is consequently limited to the planned description of concentration and safety outcomes; the posted registry information does not support a quantified account of the pharmacokinetic profile.
3. Trial Design
This was a phase 1, completed, single-group study of Ferriprox in patients with sickle cell disease. The registry lists an enrollment of 8 and describes the intervention as a single 1500 mg dose. It gives the study start as 2013-05 and primary completion as 2014-04. ApoPharma is listed as the sponsor.
The record describes allocation as NA, masking as NONE, and the model as SINGLE GROUP. There is no distinct control arm in the design described, so the study is not a randomized comparison. The dose and the participants’ measurements after dosing form the focus of the record. The registry does not report a comparator treatment, a placebo group, or a comparison between dose levels.
The primary outcome is Cmax for serum deferiprone and deferiprone 3-O-glucuronide, assessed over a 10-hour interval. Blood sampling is described from pre-dose through 10 hours after dosing, with specified post-dose sampling times. The secondary outcomes are frequency of adverse events and frequency of serious adverse events. Six outcome measures are listed, but numerical results for the primary pharmacokinetic endpoint are not reported in the registry record.
Details of the protocol beyond the registry description, including the sample-size justification, analysis plan, analysis populations, handling of missing measurements, and any interim analyses, are not reported in the registry record. The record also does not give a detailed account of the participants who contributed data to each outcome. These omissions limit how fully the study’s conduct and analysis can be reconstructed from the registration information.
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 | Ferriprox |
|---|---|
| STARTED | 8 |
| COMPLETED | 8 |
| NOT COMPLETED | 0 |
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 | Ferriprox |
|---|---|---|
| Participants analysed | 8 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 8 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 33.0 (SD 5.9) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 3 |
| Region of Enrollment: Canada | participants | 8 |
6. Primary Endpoint
The registry lists the primary outcome as Cmax for Serum Deferiprone and Deferiprone 3-O-glucuronide, measured over 10-hour interval.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | μg/mL |
| Endpoint classification | Continuous Endpoint |
Cmax is the maximum measured concentration of a substance in serum during the stated observation interval. In this study, the primary outcome concerns Cmax for deferiprone and for its 3-O-glucuronide metabolite. Both are expressed in μg/mL, and the registry describes the outcome as a mean with standard deviation over a 10-hour interval.
For pharmacokinetic description, a peak concentration helps characterize the highest measured serum exposure after a dose. It is useful alongside other features of a concentration-time profile, though the registry record does not report other numerical pharmacokinetic results. Cmax is a measured peak, not necessarily the exact concentration at every moment: its observed value depends in part on when samples are collected. The record specifies pre-dose sampling and post-dose samples at 0.25, 0.50, 0.75, 1, 1.33, 1.66, 2, 2.5, 3, 4, 6, 8, and 10 hours.
The endpoint description identifies what was to be measured, but no mean, standard deviation, or participant-level result for either analyte is reported in the registry record. Therefore, the magnitude and variability of the observed Cmax values cannot be assessed from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record gives a clear description of the primary measurement but does not report its numerical outcome. It identifies mean Cmax and standard deviation for serum deferiprone and deferiprone 3-O-glucuronide over a 10-hour interval. Without those estimates, the posted results do not show the measured peak concentrations, their variability, or how precisely either mean was estimated. No confidence intervals or analysis results are reported in the registry record.
This absence matters for interpretation. A stated endpoint is not itself a result: the endpoint description explains what investigators intended to measure, while an estimate is needed to describe what was observed. The registry also does not provide a concentration-time result from which to characterize the course of either analyte over the sampling interval. It would be inappropriate to infer a peak value from the sampling schedule or from the study objective.
The design is single-group and has no separate comparator. Accordingly, even if the Cmax values were available, the design described would support a descriptive account of concentrations following the stated dose, rather than a randomized comparison with another treatment or dose. The record does not report an analysis comparing patient subgroups, nor does it report a statistical model for the concentration measurements. Any such details are not reported in the registry record.
The registry lists 8 participants enrolled. That figure alone does not establish how many had evaluable samples for each analyte or endpoint; endpoint-specific analysis populations are not reported in the registry record. With no estimates, dispersion values, or interval estimates posted, readers cannot assess the observed variability or the precision of the primary outcome from the record.
Safety information is also limited to participant counts: 0 of 8 participants at risk were affected by a serious adverse event, and 2 of 8 were affected by another adverse event. The registry lists no serious adverse-event terms. The death count is not reported in the registry record. These entries describe the recorded counts; they do not supply a detailed account of event types, timing, severity, or any relationship to treatment.
Overall, the posted information describes the study’s purpose, design, outcome definitions, and limited adverse-event counts. It does not report the numerical pharmacokinetic findings needed to characterize Cmax or its precision. The absence of those results should not be replaced by assumptions about what the study may have observed.
9. Statistical Methods Explained
General: what the endpoint represents. Cmax is the maximum measured concentration during an observation interval. A concentration-time profile is built from blood samples collected at specified times; the largest measured value is the observed Cmax. The registry describes measurements for two analytes, deferiprone and deferiprone 3-O-glucuronide, and states that Cmax is summarized as a mean and standard deviation. It gives a 10-hour assessment interval and specifies pre-dose and post-dose sampling times. The endpoint description is not an analysis result, and the registry record does not report the numerical means or standard deviations.
General: mean and standard deviation. A mean describes the average value in the observations included in an analysis. A standard deviation describes how dispersed those observations are around the mean. They answer different questions: the mean indicates the central level, while the standard deviation indicates variability among observations. Neither alone gives a complete account of precision. For example, a confidence interval would describe a range of values compatible with an estimate under a statistical method and its assumptions. No confidence interval is reported in the registry record for either Cmax outcome.
General: sampling and a measured peak. A measured Cmax depends on the timing of samples as well as the underlying concentration pattern. A value between scheduled samples is not directly observed by the sampling schedule described in the record. The specified time points make the intended observation process more transparent, but they do not reveal the actual concentrations. The registry does not report individual concentration-time data, the method used to derive Cmax, or how incomplete sampling was handled.
General: precision and small studies. A limited number of observations can make estimates sensitive to the values of individual participants, and uncertainty may be substantial. This is a general statistical consideration, not a claim about the study’s unreported results. The registry lists enrollment of 8, but does not report the number included in each endpoint analysis or provide uncertainty estimates. Consequently, precision cannot be evaluated from the enrollment count alone.
General: distribution and variability. Statistical summaries such as means and standard deviations can be influenced by unusually high or low observations. In some data settings, values may be unevenly distributed or more variable than a simple model assumes. Over-dispersion means that variability exceeds what a chosen model expects; it can make standard errors and inferences unreliable if not accommodated. This is a general concept, not a finding about these concentration measurements. The registry record does not report the distribution of the measurements, diagnostic checks, transformations, or a model that would allow readers to assess these issues.
General: single-group interpretation. In a single-group study, measurements after dosing can describe the participants’ observed response over time, but there is no separate randomized group in this record to provide a concurrent contrast. Thus a comparison with another treatment, dose, or untreated course is not part of the design described. The record lists allocation as NA and masking as NONE. It does not report a comparative estimate or a statistical test of treatment differences.
General: planning calculations. The stated planning illustration uses a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is a stated fraction of an observed effect. For non-time-to-event outcomes, its convention is participants per arm. These are planning assumptions, not a description of the original single-group study’s design. The registry does not report a sample-size justification for the original study. No planning values or observed effect estimates are reported in the registry record, so a planning illustration cannot be interpreted as an observed result or as observed power.
The registry lists no analyses. It does not describe the statistical method used to estimate either Cmax mean, how standard deviations were calculated, whether observations were excluded, or how missing measurements were handled. It also does not report whether estimates were adjusted for any factors. Those details should not be inferred from the endpoint label or from the sampling schedule. The posted information supports a description of the intended measurement, but not a reconstruction of an analysis or a judgment about its assumptions.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists six outcome measures. The primary endpoint covers Cmax for two analytes, and the listed secondary outcomes concern frequency of adverse events and frequency of serious adverse events. Considering multiple outcomes can raise a multiplicity issue: when several statistical questions are tested, the chance of at least one apparently notable result may change. This is a general statistical concern, not a statement that such tests were performed in this study.
A prespecified analysis plan can explain which outcomes are primary, how related tests are handled, and which estimates are intended to support conclusions. Any multiplicity adjustment, hierarchy among outcomes, or planned interpretation strategy is not reported in the registry record. The record lists no analyses and does not report p-values or other inferential results. Therefore, it is not possible to determine whether multiplicity was addressed or whether any testing was conducted.
Missing-data handling is also not reported in the registry record. Although enrollment is listed as 8, the record does not state how many participants had usable measurements for each analyte, whether any samples were missing, or how incomplete concentration profiles would be treated. It does not describe imputation, exclusion rules, or sensitivity analyses. No assumptions about missing observations can be made from the enrollment count.
The analysis populations are not reported in the registry record. In particular, the record does not define which participants were included in the primary endpoint analysis or in adverse-event summaries. These omissions mean readers cannot establish whether the outcome summaries, if available, would represent all enrolled participants or a subset. They also prevent assessment of whether the analysis followed a prespecified plan.
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 |
|---|---|---|---|
| Ferriprox | 0 | 8 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Ferriprox | 2 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Ferriprox |
|---|---|---|
| Abdominal Pain | Gastrointestinal disorders | 1 of 8 |
| Oropharyngeal Pain | Respiratory, thoracic and mediastinal disorders | 1 of 8 |
| Headache | Nervous system disorders | 1 of 8 |
| Fatigue | General disorders | 1 of 8 |
| Fever | General disorders | 1 of 8 |
The safety entries list 8 participants at risk for serious adverse events and 0 affected. For other adverse events, 8 were at risk and 2 were affected. These are counts of participants recorded as affected, not a detailed account of the number or nature of individual event episodes. The registry lists no serious adverse-event terms. A death count is not reported in the registry record.
These counts should be read descriptively. The record does not provide event types for the other adverse events, timing, severity, duration, or participant-level detail. It also does not report an analysis comparing safety with a control group; the study has a single-group design. The counts therefore do not estimate a comparative difference.
General statistical context: when the number of participants is limited, an event count alone gives little information about how precisely an underlying event frequency has been estimated. A count of zero recorded serious events does not establish that serious events cannot occur, and the posted information does not include an uncertainty interval. The registry’s entries are a limited safety summary, not a complete characterization of risk.
12. What the Result Does, and Does Not, Mean
This study addresses a descriptive pharmacokinetic question: what maximum measured serum concentrations of deferiprone and deferiprone 3-O-glucuronide followed a single 1500 mg dose of Ferriprox in patients with sickle cell disease? The registry gives the intended endpoint, unit, summary type, assessment interval, and sampling schedule. It also describes a completed phase 1, single-group study with enrollment of 8.
What the posted record does not show is the numerical Cmax result for either analyte. It contains no reported mean or standard deviation for the primary endpoint, and no confidence intervals or analysis results. Therefore, it does not allow readers to quantify the observed concentrations, their dispersion, or the precision of the estimates. The record also does not report a numerical concentration-time profile.
The design does not include a separate comparator group. It cannot provide a randomized contrast between Ferriprox and another treatment or between different doses, based on the design described. Nor does this record establish a comparative treatment effect. The stated study objective is pharmacokinetic evaluation after a single dose, not a comparative efficacy question.
The safety entries report 0 participants affected by serious adverse events and 2 affected by other adverse events among 8 at risk in each category. Those limited counts do not describe event details or provide a comparative safety estimate. The death count is not reported in the registry record.
General interpretation: a result is most informative when its estimate, uncertainty, and analysis context are available together. In their absence, the endpoint definition and study design can be described, but the size and precision of the measured pharmacokinetic outcomes cannot be inferred. The registry information should not be read as proof of either a particular concentration profile or a particular clinical effect.
13. Why This Trial Matters Statistically
This study is statistically useful to consider because it separates a measurement plan from a reported finding. The registry defines Cmax for two analytes, gives units and a sampling schedule, and identifies the intended summary as a mean with standard deviation. Those details clarify what the primary outcome was meant to describe. But without numerical estimates, readers cannot evaluate the central values or variability. A clearly specified endpoint does not replace an observed result.
The single-group design also makes the scope of inference important. Measurements after a dose can be described for the studied participants, but the record contains no randomized comparison with a different dose or control group. The design should not be interpreted as answering a comparative question that it was not set up to address.
The record further illustrates why enrollment and analysis populations are distinct statistical details. Enrollment is listed as 8, while the number with evaluable measurements for each endpoint is not reported in the registry record. Without that information, even an estimate would be harder to interpret fully. The record also omits the analysis methods, missing-data handling, and multiplicity approach, leaving important aspects of precision and inference unspecified.
Finally, the adverse-event counts show how descriptive safety reporting should be framed. The entries state the number affected in the study group, but event details and comparative estimates are absent. Together, these features make the record a useful example of the limits of interpreting registry information when endpoint definitions are present but numerical outcome analyses are not.
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 for statistical interpretation is that numerical results for the primary endpoint are not reported in the registry record. No Cmax means or standard deviations are given for deferiprone or its 3-O-glucuronide metabolite. Confidence intervals, participant-level measurements, and analysis results are also not reported, so neither magnitude nor precision can be assessed.
The registry describes enrollment of 8, but does not state how many participants contributed usable data to each endpoint. Analysis populations and reasons for any missing or excluded measurements are not reported in the registry record. The record also does not explain the statistical methods used, the method for deriving Cmax, or any checks of model assumptions.
The study is single-group, with no separate comparator. It therefore provides no concurrent randomized contrast in the design described. Allocation is listed as NA and masking as NONE. The record does not report a sample-size justification or analysis plan, so the intended precision and inferential approach cannot be reconstructed.
Safety reporting is limited: the registry lists participant counts but does not provide event terms for serious events, details for other events, or the death count. The approach to multiplicity across six outcome measures and to missing data is not reported in the registry record. These limitations constrain interpretation of both the pharmacokinetic outcomes and the safety summary.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Absorption, Metabolism, and Excretion of a Single Dose of Ferriprox® in Patients With Sickle Cell Disease — NCT01835496.
- Registry record last updated 2015-07-24; status last verified 2013-04.
- Results first posted 2015-07-24.
- 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 NCT01835496 as a completed phase 1, single-group study sponsored by ApoPharma. It enrolled 8 patients with sickle cell disease to receive a single 1500 mg dose of Ferriprox. The primary endpoint was mean Cmax, with standard deviation, for serum deferiprone and deferiprone 3-O-glucuronide over a 10-hour interval. The record specifies pre-dose and post-dose blood sampling times.
Numerical primary endpoint results and analyses are not reported in the registry record. The listed safety counts are 0 of 8 affected by a serious adverse event and 2 of 8 affected by another adverse event; the death count is not reported. Analysis populations, missing-data methods, and multiplicity procedures are also not reported in the registry record.