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 Radiolabeled [14C]PF-02341066 Study To Investigate The Absorption, Metabolism And Excretion In Healthy Male Volunteers (NCT01082380), a non-randomized phase 1 study. The primary outcome is Maximum Observed Plasma Concentration (Cmax).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01082380 |
| Phase | Phase 1 |
| Condition | Healthy Volunteer |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 6 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Pfizer |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned healthy male volunteers. The registry lists the condition as Healthy Volunteer and reports an enrollment of 6. The primary pharmacokinetic analysis population was defined as treated participants with at least 1 of the primary pharmacokinetic parameters of interest. The registry does not report further eligibility details, such as age limits or specific health-screening criteria, so the population cannot be characterized more narrowly from this record.
Intervention
The intervention was PF-02341066, administered as a single radiolabeled dose according to the official study title. The stated rationale was to investigate absorption, metabolism and excretion, characterize plasma, fecal and urinary radioactivity, and identify metabolites if possible. A safety group is labeled PF-02341066 250 mg. The registry does not give a fuller dosing schedule or additional administration details in the record.
Comparator
There was no randomized or control group. The study is classified as non-randomized, unmasked and single-group. Its design therefore does not support a like-for-like comparison between treatment groups. The purpose described in the registry is characterization of the drug and radioactivity in humans, rather than estimating a contrast against a placebo or another treatment.
Primary question
The stated primary endpoint was maximum observed plasma concentration (Cmax), expressed in ng/mL and characterized using a geometric mean and standard deviation. The question is how high plasma concentration was observed after dosing, assessed over the stated sampling schedule. The actual Cmax result is not reported in the registry record, so its magnitude and precision cannot be assessed from the posted information.
This is a descriptive pharmacokinetic question, not a test of comparative clinical benefit. The registry rationale also includes broader questions about absorption, metabolism, excretion and possible metabolites. Those aims give context for the sampling and measurement program, but the record does not supply the corresponding detailed outcome values in the information available for this analysis. Accordingly, the design can be described, but the results cannot establish how much drug or radioactivity was present in the measured materials or what metabolites were identified.
3. Trial Design
This was a Phase 1, open-label, non-randomized, single-group study. The official title describes a single-radiolabeled-dose investigation in healthy male volunteers. The registry lists an enrollment of 6 and marks the study completed. The recorded start was 2010-03 and primary completion was 2010-04. Pfizer is listed as the sponsor. These details describe the registered study; they do not establish when individual participants were dosed or how long each person contributed data.
Because there was one group and no random allocation, the study was not structured as a treatment-versus-control comparison. Its stated aim was to characterize absorption, metabolism and excretion of radiolabeled PF-02341066, including plasma, fecal and urinary radioactivity and possible metabolites. The registry records PF-02341066 as the intervention. The safety group label specifies PF-02341066 250 mg, but the record does not provide a fuller account of administration or dosing procedures in the material.
The primary pharmacokinetic parameter was maximum observed plasma concentration, or Cmax. Sampling was scheduled pre-dose and at 1, 2, 3, 4, 6, 8, 10, 12, 16, 24, 36 and 48 hours, then after every 24 hours until up to 480 hours post-dose. This schedule indicates repeated measurement over time, but the registry does not report the observed concentration profile or Cmax value. The pharmacokinetic analysis population included treated participants who had at least 1 of the primary parameters of interest.
The registry lists 30 outcome measures and 0 analyses. Those counts do not provide the outcome values, analysis details or reasons for their absence. The statistical analysis plan, sample-size justification, interim-analysis plan and handling of protocol deviations are not reported in the registry record. The study’s completed status should therefore be distinguished from the availability of a complete results narrative.
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 | PF-02341066 250 mg |
|---|---|
| STARTED | 6 |
| COMPLETED | 6 |
| NOT COMPLETED | 0 |
Analysis population for the primary outcome, as defined in the registry: The Pharmacokinetic (PK) parameter analysis population included all treated participants who had at least 1 of the PK parameters of primary interest.
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 | PF-02341066 250 mg |
|---|---|---|
| Participants analysed | 6 | |
| Age Continuous | years | 43.2 (SD 1.8) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 6 |
6. Primary Endpoint
The registry lists the primary outcome as Maximum Observed Plasma Concentration (Cmax), measured over Pre-dose, 1, 2, 3, 4, 6, 8, 10, 12, 16, 24 hours (hrs), 36 hrs, 48 hrs, then after every 24 hrs until up to 480 hrs post-dose.
| Element | Registry entry |
|---|---|
| Result type | Geometric Mean |
| Measure of spread | Standard Deviation |
| Unit | ng/mL |
| Endpoint classification | not reduced to a single comparison |
Maximum observed plasma concentration (Cmax) is the highest measured plasma concentration within the sampling period. It is a pharmacokinetic summary: it describes the observed peak concentration rather than the total amount of drug exposure over time, the time at which the peak occurs, or a clinical response. The registry specifies ng/mL as the unit and identifies the planned summary as a geometric mean with standard deviation.
In general, Cmax is used to characterize the concentration profile after a dose. It can help describe how much of a measured substance reached the circulation at its observed peak. Its interpretation depends on the sampling schedule: the reported maximum is the highest measured value, and a peak between scheduled samples may not be captured directly. Here, measurements were scheduled from pre-dose through 48 hours and then at 24-hour intervals until up to 480 hours post-dose. That schedule gives the planned observation window, but does not by itself show what concentrations were measured or when any peak occurred.
A geometric mean is a summary suited to positive measurements that may be distributed asymmetrically; in general, it summarizes values on a multiplicative scale. The registry also names standard deviation as the dispersion measure, but does not report the actual Cmax estimate, its standard deviation, participant-level observations or a confidence interval. Consequently, the endpoint definition and planned summary are known, while the observed result and its precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a pharmacokinetic endpoint and a sampling plan, but does not report the observed Cmax value. It also does not report a standard deviation or confidence interval for that endpoint. Without those results, readers cannot assess the observed peak concentration, the variability across participants, or the precision of the estimated geometric mean. The listed endpoint is therefore interpretable as a planned measurement, not as a numerical finding.
The study’s single-group, non-randomized design is consistent with its stated characterization purpose. It has no control group against which to estimate a treatment contrast. Any description of measurements from the treated group would be descriptive, not evidence of a randomized comparative effect. The record does not report an estimated effect or a comparator, and no conclusion about relative effects can be drawn from the design information alone.
The analysis population was defined as treated participants with at least 1 of the primary pharmacokinetic parameters of interest. This definition matters because enrollment and analysis populations are not automatically identical: treatment, parameter availability and analysis eligibility can affect which observations enter a particular summary. The record does not report the number included in the Cmax analysis or participant-level missingness. It is therefore not possible to determine whether all enrolled participants contributed to that endpoint.
The posted safety figures report 0 participants with a serious adverse event among 6 at risk in the PF-02341066 250 mg group. The registry also reports 6 with other adverse events among 6 at risk. These are descriptive counts for the recorded group. The record does not provide event terms for serious events, and the deaths value is not reported in the registry record. The safety information does not fill the gap in the primary pharmacokinetic result.
A registry record can describe a study’s objectives, design and planned measures without making all observed data available. In this case, the stated rationale is broad, covering absorption, metabolism, excretion, radioactivity in several materials and possible metabolite identification. The primary Cmax result and detailed results for those broader aims are not reported in the registry record. The completed status does not itself indicate what the measurements showed.
The planning illustration is based on an observed effect and specifies a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It is explicitly a planning illustration rather than the trial’s own design. Since this study is single-group and the primary result is not reported, such a calculation should not be read as observed power or as a direct description of this study’s design. The registry does not report a trial-specific sample-size justification.
9. Statistical Methods Explained
What does Cmax describe?
Maximum observed plasma concentration is the largest measured concentration in plasma during the observation period. It is a compact description of the peak in a concentration-time profile. It does not describe the entire profile: two profiles can have the same peak and different durations or overall exposure. In general, Cmax is used alongside other pharmacokinetic parameters to characterize what happens after dosing. The registry names Cmax as the primary endpoint, but the corresponding observed value is not reported in the registry record.
The word “observed” is important. A measurement schedule captures concentrations at selected times, and the maximum of those measurements is the maximum observed value. A true peak between scheduled samples may not be directly measured. The planned schedule began pre-dose, included measurements through 48 hours, and continued after every 24 hours until up to 480 hours post-dose. The schedule alone cannot establish the concentration at any time point or the timing of an individual peak.
Why report a geometric mean?
In general, a geometric mean summarizes positive values after expressing them on a logarithmic scale and then returning the summary to the original scale. This can be useful when measurements vary multiplicatively or have a right-skewed distribution, as concentration data sometimes do. It differs from an arithmetic mean, which averages values directly. The registry specifies a geometric mean for Cmax and standard deviation as the dispersion measure. It does not report the estimated geometric mean, the dispersion value, the data distribution or the method used to calculate the summary. The choice named in the record therefore tells readers what summary was intended, but not what the data showed.
A standard deviation describes the spread of observations around a mean on the scale used for the analysis. It is not the same as a confidence interval. A confidence interval, in general, expresses uncertainty about an estimated population quantity under the assumptions of the analysis. No confidence interval for Cmax is reported in the registry record, so precision cannot be judged using such an interval. Nor can a standard deviation be reconstructed from the information recorded.
What does a single-group design permit?
A single-group study measures participants receiving the intervention without a concurrent comparison group. In general, this design can describe measured concentrations and safety observations in that group. It cannot estimate a randomized contrast with an untreated group or another treatment. Randomization is useful in comparative studies because it supports balance between groups in expectation; it is not part of this study’s design. The registry classifies the allocation as non-randomized and the model as single-group, so a comparative treatment effect is not the relevant estimand in the posted design.
Open-label means that the study is not masked. For an objective laboratory concentration, the measurement itself is less dependent on a participant’s reported experience than a subjective outcome would be, but open-label status still describes the study’s conduct and does not remove all possible sources of bias. The registry does not report further procedures for laboratory assessment, sample handling, assay validation or blinded data review. Those details cannot be assumed.
How should the analysis population be understood?
The registry defines the pharmacokinetic parameter analysis population as treated participants with at least 1 of the primary parameters of interest. This is an eligibility rule for inclusion in the analysis, not a statement that every enrolled participant contributed every measurement. In general, missing measurements can arise for different reasons, and the choice of analysis population affects which observations support a summary. The record does not provide endpoint-specific participant counts, missing-data reasons, imputation methods or sensitivity analyses. As a result, the extent and handling of missing Cmax data are not reported in the registry record.
Repeated sampling creates observations within participants. In general, measurements from the same person are related and should not be treated as independent observations when an analysis models the full concentration profile. A summary such as Cmax reduces the profile to a participant-level quantity, but the record does not describe the detailed analysis methods used for the primary endpoint. The number of listed outcomes does not reveal which model, transformations or estimation procedures were applied.
What do the planning assumptions mean?
The registry describes a planning illustration computed from an observed effect, not the trial’s own design. It specifies a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, with the target effect expressed as a stated fraction of the observed effect. In general, such an illustration asks how many participants a hypothetical future comparison might require under its assumptions. It is not a measure of the probability that this completed study found a real effect, and it is not observed power.
The illustration’s assumptions concern a two-arm comparison, whereas this study is registered as a single-group study. The registry also does not report the primary Cmax estimate needed to identify an observed effect for a planning exercise. The planning assumptions should therefore be separated from the study’s actual design and from evidence about its measured results. No trial-specific sample-size justification or statistical analysis plan is reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 30 outcome measures, while the record summarized for this analysis gives 0 analyses. A long list of outcomes can involve multiple statistical questions, but the count alone does not establish which outcomes were formally tested, whether hypotheses were prespecified, or whether any adjustment for multiple testing was used. The multiplicity plan is not reported in the registry record. It would therefore be inappropriate to infer that the primary endpoint was protected from multiplicity, or that all listed measures were treated as confirmatory.
The primary pharmacokinetic analysis population included treated participants with at least 1 of the primary parameters of interest. This tells readers the stated eligibility criterion, but not how many participants contributed to Cmax or to other parameters. Endpoint-specific analysis counts, reasons for missing data, exclusions and methods for handling missing measurements are not reported in the registry record. No imputation or sensitivity-analysis approach is described.
The distinction between the enrollment figure and the analysis population is important in general: a participant may be enrolled without contributing usable data to every endpoint. The record does not give enough detail to determine whether this occurred for Cmax. It also does not report a protocol-deviation approach, an interim-analysis plan, or a statistical analysis plan. These omissions limit assessment of prespecification and the potential influence of missing measurements or multiple outcomes. The absence of those details is not evidence that a particular method was or was not used; it means the method is not reported in the registry record.
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 |
|---|---|---|---|
| PF-02341066 250 mg | 0 | 6 | 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 |
|---|---|
| PF-02341066 250 mg | 6 of 6 |
Most frequent non-serious adverse event terms
| Event term | Organ system | PF-02341066 250 mg |
|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 4 of 6 |
| Abdominal discomfort | Gastrointestinal disorders | 1 of 6 |
| Abdominal pain upper | Gastrointestinal disorders | 1 of 6 |
| Constipation | Gastrointestinal disorders | 1 of 6 |
| Dyspepsia | Gastrointestinal disorders | 1 of 6 |
| Somnolence | Nervous system disorders | 1 of 6 |
| Seborrhoeic dermatitis | Skin and subcutaneous tissue disorders | 1 of 6 |
| Skin exfoliation | Skin and subcutaneous tissue disorders | 1 of 6 |
The registry reports 0 participants with a serious adverse event among 6 at risk in the PF-02341066 250 mg group. It reports 6 participants with other adverse events among 6 at risk in that group. These are participant counts as recorded for the safety categories; they do not describe event severity beyond the category labels, event duration, causal attribution or clinical course. The record lists no serious-event terms, so specific serious-event descriptions are not reported in the registry record.
The deaths field is null, which means a death count is not reported in the registry record. It should not be converted into a claim that no deaths occurred. Similarly, the reported count of participants with other adverse events does not show how many separate events occurred, what they were, or whether they were considered related to the intervention. The registry record does not provide that detail in the information.
These safety counts are descriptive and come from a single-group study. There is no control group for comparing event counts. They should not be interpreted as a comparative risk estimate or as a complete account of safety. The record’s safety figures also do not provide information about the primary pharmacokinetic result, which is not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The record establishes that a completed Phase 1 study was registered to investigate radiolabeled PF-02341066 in healthy male volunteers. Its stated rationale covered absorption, metabolism and excretion, characterization of plasma, fecal and urinary radioactivity, and possible metabolite identification. It also specifies maximum observed plasma concentration as the primary endpoint and describes the planned sampling schedule. These details show what the study set out to measure, not what the measurements found.
The actual primary Cmax estimate and its dispersion are not reported in the registry record. Without those values, the concentration result cannot be described quantitatively, and its precision cannot be evaluated. The record also does not report the relevant detailed outcome values for the broader characterization aims in the information. A completed status does not supply those missing results or establish that any particular finding was observed.
The design is single-group, open-label and non-randomized. It can support descriptive characterization of measurements in the treated group if those results are reported, but it does not supply a concurrent control comparison. No comparative treatment effect should be inferred from this design. Likewise, the safety counts do not establish a comparison with another group or identify causes of events.
The record does not report a trial-specific sample-size justification, a full statistical analysis plan, detailed missing-data handling or a multiplicity strategy. These omissions constrain assessment of how the outcomes were analyzed and how robust any estimates might be. They do not establish that the study was poorly conducted; they limit what can be concluded from the registry information available.
In general, pharmacokinetic measures describe concentrations and their timing, while clinical benefit and harm require appropriate clinical outcome evidence. Cmax alone is not a measure of clinical effectiveness. The stated purpose is characterization, and the posted primary result is unavailable in the registry record. The defensible interpretation is therefore limited to the registered aim, design and reported safety counts, rather than a claim about the magnitude or consequences of the pharmacokinetic findings.
13. Why This Trial Matters Statistically
This study illustrates the distinction between a registered measurement plan and an interpretable numerical result. The registry names Cmax, its unit, its summary form and an extensive sampling schedule. Those details are statistically useful because they identify the target quantity and indicate how observations were intended to be collected. Yet without the reported estimate and variability, the endpoint cannot answer the quantitative question posed by the study.
It also demonstrates why design determines the kind of inference available. A single-group study can be suited to descriptive pharmacokinetic characterization, but it does not create a randomized contrast. Readers should not treat a within-group measurement as evidence of a comparative effect. The design’s purpose and its limitations need to be read together.
The stated analysis population is another important part of interpretation. Requiring treatment and at least 1 primary parameter does not establish that every enrolled participant contributed to every analysis. Endpoint-specific counts and missing-data methods would help readers understand the basis of each summary. Their absence means that the precision and completeness of the primary analysis cannot be assessed.
Finally, the record illustrates the difference between an actual trial design and a hypothetical planning calculation. A planning illustration based on an observed effect and two-arm assumptions does not describe this single-group study’s design and is not observed power. Statistical quantities are meaningful only in relation to the population, estimand, design and assumptions they represent. The registry supplies some of that context, but the missing primary result prevents a full appraisal of the study’s central pharmacokinetic finding.
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 principal limitation for interpreting this study is that the primary Cmax result is not reported in the registry record. The geometric mean, standard deviation and any confidence interval are also not reported there. The sampling schedule is specified, but the observed concentration-time data and the timing of the maximum are unavailable in the information. As a result, neither the magnitude nor the precision of the primary endpoint can be assessed.
The single-group, non-randomized design offers no concurrent control comparison. That is consistent with the stated characterization aim, but it limits the kinds of conclusions the design can support. The registry also does not describe the detailed assay procedures, handling of samples, or analysis of the broader radioactivity and metabolite outcomes. Those elements should not be inferred from the stated rationale.
The analysis population rule is given, but the number contributing to Cmax, endpoint-specific missingness, exclusion details and methods for handling missing measurements are not reported in the registry record. The multiplicity strategy and statistical analysis plan are also not reported. These gaps make it difficult to evaluate prespecification and the analytical basis for any estimates that might exist outside the record.
The safety information is limited to group counts. Specific event terms, causal assessments and a reported death count are not available in the record; the deaths value is not reported in the registry record. The enrollment figure and completed status do not resolve these information gaps or establish the completeness of the posted results.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Radiolabeled [14C]PF-02341066 Study To Investigate The Absorption, Metabolism And Excretion In Healthy Male Volunteers — NCT01082380.
- Registry record last updated 2012-02-29; status last verified 2012-02.
- Results first posted 2011-10-26.
- 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
This completed Phase 1 study was an open-label, non-randomized, single-group investigation of radiolabeled PF-02341066 in healthy male volunteers. The registry lists an enrollment of 6, a start of 2010-03, primary completion in 2010-04, and Pfizer as sponsor. The stated aim was to characterize absorption, metabolism and excretion, including radioactivity in plasma, feces and urine and possible metabolite identification.
The primary endpoint was maximum observed plasma concentration (Cmax), summarized as a geometric mean with standard deviation and measured in ng/mL. The primary result and its dispersion are not reported in the registry record. Safety counts include 0 participants with serious adverse events and 6 with other adverse events among 6 at risk in the PF-02341066 250 mg group. A death count is not reported in the registry record. The design supports descriptive characterization, not a randomized comparison.