Dose Titration Investigation of the Pharmacokinetics of Testosterone Transdermal Systems in Hypogonadal Men: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Dose Titration Investigation of the Pharmacokinetics of Testosterone Transdermal Systems in Hypogonadal Men (NCT01104246), a na phase 1 study. The primary outcome is Time-average (Cavg) Steady State Testosterone Concentration Over 24 Hours.

2. Clinical Question

The clinical question is pharmacokinetic rather than a comparison of treatment outcomes between groups. Pharmacokinetics concerns how drug concentration changes over time in the body. In this study, the endpoint represents an average concentration across a 24-hour sampling period, assessed at the specified time after starting treatment. The registry summary also identifies metabolism and safety as areas of investigation, but does not supply detailed metabolism results.

The record describes an open-label investigation with no masking and no randomized comparison. Consequently, the endpoint can describe the concentration measured in the analysed participants, but the record does not support estimating a difference against an untreated or active-control group. The primary numerical endpoint result is not reported in the registry record, so its size and precision cannot be assessed from the posted results.

3. Trial Design

This was a completed, open-label, single-group Phase 1 study sponsored by Watson Pharmaceuticals. The registry record lists an enrollment of 40 and the condition of hypogonadism. The study title describes dose titration of testosterone transdermal systems, and the brief summary states that pharmacokinetics at steady state would be evaluated in hypogonadal men.

Allocation is recorded as not applicable, masking as none, and the model as single group. These features mean that the record does not describe randomized assignment, blinding, or a separate control arm. The study is therefore not a randomized comparison, and its intervention group should not be interpreted as if it had a like-for-like control group. The specific titration schedule and dose levels are not reported in the registry record.

The primary endpoint was a continuous measure: time-average (Cavg) steady-state testosterone concentration over 24 hours, in ng/dL. A 24-hour pharmacokinetic sampling was performed on Day 28/29 after the start of dosing. The primary analysis used the per-protocol population. That population included participants who completed the treatment period, did not have more than two consecutive missing data, and had no major protocol deviations. The number who met those criteria is not reported in the registry record.

The record gives a study start of 2010-04, primary completion of 2010-09, and status as completed. It lists one outcome measure but no analysis results. The planned sample-size justification, detailed statistical analysis plan, and any interim analyses are not reported in the registry record. In particular, the enrollment figure alone does not establish how the study size was chosen or how precisely the endpoint could be estimated.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Per-protocol Population was used for the analysis. PP population included subjects who completed the treatment period of the study, who did not have more than two consecutive missing data, and who did not have any major protocol deviations.

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.

6. Primary Endpoint

The registry lists the primary outcome as Time-average (Cavg) Steady State Testosterone Concentration Over 24 Hours, measured over Day 28/29.

The primary endpoint is the time-average (Cavg) steady-state testosterone concentration over 24 hours, reported in ng/dL. It was assessed using 24-hour pharmacokinetic sampling on Day 28/29 after dosing began. The registry record specifies that the endpoint is summarized as a mean with a standard deviation and that the primary analysis population is per protocol.

As a general statistical concept, an average across a defined sampling period can describe the overall concentration profile during that period rather than relying on a single measurement. A steady-state assessment is intended to characterize concentrations once the dosing regimen has reached the state targeted by the study; the registry summary identifies the assessment as steady state but does not give further operational criteria for reaching it.

The mean describes the central value in the analysed participants, while the standard deviation describes how dispersed individual values are around that mean. These summaries would help readers understand both the typical measured concentration and its variability. However, the numerical mean and standard deviation are not reported in the registry record. Nor is a confidence interval or other measure of the estimate’s precision reported. As a result, the endpoint’s observed level and variability cannot be interpreted from the posted results.

This pharmacokinetic endpoint does not, by itself, establish a clinical benefit or compare outcomes against another treatment. The registry record’s description of metabolism and safety as study topics does not add numerical results for those topics beyond the adverse-event counts described separately.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean represent?

The primary measure is continuous: time-average (Cavg) steady-state testosterone concentration over 24 hours, in ng/dL. A continuous outcome can take values across a measurement scale rather than being limited to categories. The registry record specifies the mean as the summary parameter. In general, the mean gives a central summary of the values in the analysis population. Its interpretation depends on the measured observations and the population included in the analysis.

The record also specifies a standard deviation. In general, the standard deviation describes the spread of individual observations around the mean. It is not the same as the uncertainty in the estimated mean: a confidence interval is commonly used to express that uncertainty. Neither the primary mean, standard deviation, nor a confidence interval is reported in the registry record. Thus the endpoint’s central value, dispersion, and estimation precision cannot be evaluated from the posted results.

Why use a time-average concentration?

The endpoint averages concentration over a defined 24-hour sampling period. As a general pharmacokinetic concept, summarizing measurements over time can describe exposure across the interval, rather than describing only one time point. The study’s 24-hour sampling took place on Day 28/29 after the start of dosing, and the endpoint is identified as a steady-state measure. The registry record does not provide further details about the sampling schedule, dose adjustments, or criteria used to establish steady state.

A time-average concentration can be useful for describing the concentration profile across the specified period, but it does not answer every pharmacokinetic or clinical question. The posted record does not provide other concentration summaries, individual profiles, or numerical metabolism findings. It also does not establish a comparison against a separate group.

What does the per-protocol population mean?

The primary analysis used the per-protocol population. The registry record defines this population as participants who completed the treatment period, did not have more than two consecutive missing data, and did not have major protocol deviations. This definition makes the analysis conditional on meeting the stated criteria. The number meeting those criteria is not reported in the registry record.

As a general statistical consideration, restricting an analysis to participants who meet protocol criteria can make the analysed population differ from everyone enrolled. If completion, missing measurements, or protocol deviations are related to the endpoint, the resulting estimate may not describe all enrolled participants in the same way. The record does not report analyses comparing the per-protocol population with other populations, and it does not specify how missing measurements were handled beyond the stated eligibility rule.

What can the study design estimate?

The record identifies a single-group, open-label design, with no masking and allocation listed as not applicable. In general, a single-group study can describe observations in its participants, but without a comparator it cannot estimate a difference between the intervention and a control group. Open-label status means the record does not describe masking; it does not, on its own, determine the direction or size of any measurement or reporting bias.

The registry record does not report an inferential analysis for the primary measure. It lists one outcome measure and zero analyses. No model, hypothesis test, covariate adjustment, or confidence-interval method is reported in the registry record. It would therefore be inappropriate to infer an analysis method from the endpoint type alone.

How should planning calculations be read?

The record’s planning assumptions describe an illustration based on a fraction of an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The record distinguishes total events for time-to-event illustrations from participants per arm for other illustrations. These assumptions describe planning calculations, not the original design of this single-group study. The equal-allocation, two-arm setup does not match the recorded study design.

As a general concept, power calculations estimate the sample size associated with detecting a specified effect under stated assumptions. They are planning illustrations, not observed power and not evidence that an effect was detected. The observed primary endpoint result is not reported in the registry record, so the effect underlying the illustration cannot be assessed from the posted results. The study’s own sample-size justification is not reported in the registry record.

What is not available for evaluating the analysis?

The registry record does not report the numerical primary outcome, a confidence interval, a p-value, an analysis population size, or details of any interim analyses. It also does not report a full statistical analysis plan. These absences constrain interpretation: the endpoint is defined, but the posted information does not allow readers to assess the size, variability, or inferential uncertainty of the result.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Testosterone Transdermal Systems")
n   <- c(35)
m   <- c(463)
sp  <- c(122.1)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Testosterone Transdermal Systems  35  463.000  122.100  421.057  504.943

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure and identifies a primary endpoint. It lists zero analyses, and no analysis results are reported. A multiplicity adjustment or a broader family of statistical tests is not reported in the registry record. The absence of a reported adjustment does not establish that none was planned; the full statistical plan is not reported in the registry record.

The primary analysis population was per protocol. It included participants who completed treatment, had no more than two consecutive missing data, and had no major protocol deviations. The record does not state the number included in this population. It also does not describe how missing values were treated in the analysis, whether measurements were imputed, or whether sensitivity analyses were conducted. Those details are not reported in the registry record.

As a general statistical point, missing outcome measurements can affect both the amount of information available and the conclusions drawn from an analysis. Excluding participants under per-protocol criteria may also make the analysed group differ from the enrolled group. Whether either issue materially affected this study cannot be determined from the posted results. No alternative analysis population or missing-data assessment is reported in the registry record.

The study enrolled 40 participants, but that number should not be treated as the endpoint analysis denominator because the primary analysis used eligibility criteria that could exclude participants. The registry record does not report the final per-protocol count or a participant flow accounting for exclusions and missing endpoint data.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The safety figures list 40 participants at risk for serious adverse events and 0 participants affected. For other adverse events, 40 participants were at risk and 9 were affected. These are counts within the testosterone transdermal systems group. No serious adverse-event terms are listed in the record. Deaths are not reported in the registry record.

As a general statistical point, a count of participants with an event describes what was recorded in the study group; it does not by itself establish whether an event was caused by the intervention. The record gives no control group for comparison, so these counts cannot be used to estimate a relative difference in safety between groups. The counts also do not provide detailed information about event timing, severity among non-serious events, or participant-level follow-up.

The reported at-risk counts are 40 for each adverse-event category, but the record does not give further detail about duration of observation or how adverse events were collected. The absence of listed serious-event terms is not the same as a detailed account of all safety findings. These figures should therefore be read as the registry’s reported counts, not as a complete characterization of safety.

13. What the Result Does, and Does Not, Mean

The record establishes that a completed Phase 1 study evaluated testosterone pharmacokinetics during dose titration in hypogonadal men. It specifies a primary endpoint, a 24-hour sampling period on Day 28/29, and a per-protocol analysis population. It also reports adverse-event counts for the single study group.

However, the registry record does not report the primary endpoint’s numerical mean or standard deviation, nor does it list an analysis result. The concentration level, the variability among participants, and the precision of any estimate therefore cannot be described from the posted results. A confidence interval and inferential test result are also not reported in the registry record.

The study’s single-group, open-label design does not provide a like-for-like control comparison. Accordingly, the record cannot establish a comparative effect against another treatment or control condition. The study title and summary identify pharmacokinetics, metabolism, and safety as areas of investigation, but detailed metabolism findings are not reported in the registry record.

The safety counts indicate 0 participants with serious adverse events and 9 with other adverse events among 40 at risk in the study group. These figures do not, without a comparator and additional detail, quantify a comparative safety difference or establish causation. Deaths are not reported in the registry record.

In general, a study can be informative about the measurements collected in its participants even when it does not answer comparative questions. Here, the endpoint and design are described, but the absence of numerical primary results leaves the central pharmacokinetic finding unavailable for interpretation. The registry record also does not report the per-protocol sample size, detailed missing-data handling, or the study’s sample-size justification.

14. Why This Trial Matters Statistically

This study is statistically notable for the distinction between a clearly specified measurement and an unavailable numerical result. The record identifies a continuous primary endpoint, its unit, a mean and standard deviation summary, the sampling interval, and the analysis population. Those details define what the study intended to describe, but without the endpoint values they do not show the observed concentration or its variability.

The single-group structure is also central to interpretation. A single-group pharmacokinetic investigation can describe measurements in participants exposed to the study intervention, but the registry record does not include a control group for estimating a between-group contrast. This matters because a within-group measurement and a comparative treatment effect are different statistical quantities.

The per-protocol definition gives some information about who contributed to the primary analysis: participants had to complete treatment, avoid more than two consecutive missing data, and have no major protocol deviations. Yet the number meeting those criteria is not reported. Readers therefore cannot determine the endpoint analysis denominator or assess how much the population was narrowed from the enrollment of 40.

The record also illustrates why planning assumptions should be separated from study results. The sample-size assumptions describe an illustration using equal allocation between two arms and a fraction of an observed effect, whereas the recorded trial is single group. Such planning values are not the trial’s original design and are not observed power. The numerical endpoint result underlying an observed-effect illustration is not reported in the registry record.

For statistical interpretation, the main contribution of the record is thus its description of the study question, endpoint, timing, and analysis population. The absence of numerical results prevents assessment of the endpoint’s magnitude and precision, while the noncomparative design limits causal and comparative claims.

15. 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 interpreting the study’s main question is that the numerical endpoint result is not reported in the registry record. Although the measure is defined as a mean with a standard deviation, neither statistic is available, and no confidence interval or inferential result is listed. The magnitude and precision of the pharmacokinetic estimate therefore cannot be assessed.

The study is recorded as single group, open label, and without masking. Allocation is not applicable, and no comparator is described. This design does not support a like-for-like estimate of a difference against a control group. The record also does not provide dose levels, titration details, or further operational criteria for the steady-state assessment.

The primary analysis used a per-protocol population that excluded participants who did not complete treatment, had more than two consecutive missing data, or had major protocol deviations. The final size of that population is not reported. The record does not describe participant flow, missing-data handling beyond the eligibility rule, sensitivity analyses, or results from another analysis population.

Additional statistical details are not reported in the registry record, including the full analysis plan, any interim analyses, and the sample-size justification. The planning assumptions describe an equal-allocation, two-arm illustration that does not match the recorded single-group design. Those calculations should not be treated as the study’s design or as observed power.

Safety reporting is limited to the counts of participants affected by serious and other adverse events. Serious-event terms are not listed, and deaths are not reported in the registry record. Further details about event timing, follow-up, and collection are not reported.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Dose Titration Investigation of the Pharmacokinetics of Testosterone Transdermal Systems in Hypogonadal Men — NCT01104246.
• Registry record last updated 2012-10-05; status last verified 2012-10.
• Results first posted 2011-02-23.
• 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.

19. Record Summary

The registry record describes a completed, open-label, single-group Phase 1 investigation of testosterone transdermal systems in hypogonadal men. Enrollment was 40. The study evaluated pharmacokinetics at steady state, with a primary endpoint of time-average testosterone concentration over 24 hours in ng/dL, sampled on Day 28/29 after dosing began.

The primary endpoint was summarized as a mean with a standard deviation and analysed in a per-protocol population. That population required treatment completion, no more than two consecutive missing data, and no major protocol deviations. Its size and the numerical endpoint result are not reported in the registry record. No analysis results are listed.

The adverse-event record reports 0 participants with serious adverse events and 9 with other adverse events among 40 at risk. The study has no reported comparator group, and deaths are not reported in the registry record. The primary endpoint’s magnitude and precision cannot be interpreted from the posted results.