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 Multicenter Extension Trial to Evaluate the Safety of Testosterone Gel (NCT01703741), a na phase 3 study. The primary outcome is Percentage of Subjects With a Serum Total Testosterone Level - Maximum Observed Concentration (Cmax) of 1500-1799, 1800-2499, or Above 2500 ng/dL.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01703741 |
| Phase | Phase 3 |
| Condition | Adult Male Hypogonadism |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 145 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Ferring Pharmaceuticals |
| Results posted | Yes |
2. Clinical Question
Population
The trial enrolled adult males with hypogonadism and recorded enrollment of 145 participants. The primary endpoint used a per-protocol analysis population: participants with 24-hour pharmacokinetic data for testosterone and no major protocol violations. The number included in that endpoint analysis is not reported in the registry record, so enrollment should not be treated as the endpoint denominator.
Intervention
Participants received testosterone gel applied daily in the morning using an applicator. The listed intervention is FE 999093, while the adverse-event group is labeled FE 999303; the registry record therefore uses different product codes in these entries. The dose was based on the dose fixed in the preceding 000023 study, with possible downward adjustment according to serum testosterone levels.
Comparator
This was a single-group extension trial, with no randomized comparison group identified. Allocation is recorded as not applicable and masking as none. The record does not describe a concurrent placebo or active-control group. Consequently, the trial’s registered design does not support a like-for-like comparison between gel and another treatment.
Primary question
The primary question was what percentage of participants had a maximum observed serum total testosterone concentration in any of the listed high-concentration categories: 1500–1799 ng/dL, 1800–2499 ng/dL, or above 2500 ng/dL. The registry describes the measurements and analysis population but does not report the category counts or percentages. The endpoint’s observed result is therefore not reported in the registry record.
3. Trial Design
This completed Phase 3 study was a multicenter extension trial of testosterone gel in adult males with hypogonadism. Enrollment was 145. The record identifies a single-group model, allocation as not applicable, and no masking. These design features distinguish the study from a randomized controlled comparison: the posted design describes participants receiving gel, not assignment to gel or a concurrent control treatment.
The intervention is listed as Testosterone Gel (FE 999093), while the adverse-event group is named Testosterone Gel (FE 999303). The arm description says participants received a dose fixed on Day 56 of study 000023—23 mg, 46 mg, or 69 mg—and that the dose could be down-titrated based on serum testosterone levels at Day 90/91 of that study. Gel was applied daily in the morning using an applicator. The available arm description ends before it completes its account of application, so no further application detail can be stated.
The primary endpoint concerned the maximum observed serum total testosterone concentration, or Cmax, during pharmacokinetic sampling. Samples were scheduled before dosing and at specified post-dose times between Month 3 and Month 6, after participants had been on a stabilized dose for at least one month. The primary analysis population was per protocol and required 24-hour testosterone pharmacokinetic data without major protocol violations.
The registry lists secondary outcomes covering testosterone concentration ranges, questionnaire domains, and testosterone and dihydrotestosterone exposure. The status is completed, with a recorded start of 2012-12 and primary completion of 2013-10. A detailed statistical analysis plan, sample-size justification, and interim-analysis plan are not reported in the registry record.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Of the 172 subjects who completed study 000023 (NCT01665599), 145 subjects were enrolled into this extension study and continued to receive treatment (23 mg, 46 mg or 69 mg).
Overall Study
| Stage | Testosterone Gel (FE 999303) |
|---|---|
| STARTED | 145 |
| Per Protocol (PP) Population | 106 |
| COMPLETED | 127 |
| NOT COMPLETED | 18 |
Reasons for not completing this period:
| Reason | Testosterone Gel (FE 999303) |
|---|---|
| Withdrawal by Subject | 6 |
| Adverse Event | 2 |
| Physician Decision | 2 |
| Protocol Violation | 1 |
| Lost to Follow-up | 3 |
| Subject did not want to continue | 2 |
| Subject cannot comply with study visits | 1 |
| Subject started testosterone injections | 1 |
Analysis population for the primary outcome, as defined in the registry: PP analysis population was used which comprises data from subjects who had 24 hr PK data for testosterone, with no major protocol violations.
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.
Population: Intent-to-treat (ITT) Population consists of all subjects who received at least one dose of Investigational Medicinal Product (IMP).
| Characteristic | Unit | Testosterone Gel (FE 999303) |
|---|---|---|
| Participants analysed | 145 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 116 |
| Age, Categorical: >=65 years | Participants | 29 |
| Age, Continuous | years | 57.1 (SD 9.4) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 145 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 12 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 133 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 |
| Race (NIH/OMB): Asian | Participants | 2 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 14 |
| Race (NIH/OMB): White | Participants | 127 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Percentage of Subjects With a Serum Total Testosterone Level - Maximum Observed Concentration (Cmax) of 1500-1799, 1800-2499, or Above 2500 ng/dL, measured over Samples were collected at pre-dose; 2, 4, 6, 8, 10, 12 (±15 min for all), 18 (±2 hr), and 24 (±1 hr) hours post-dose (between Month 3 and Month 6, after subjects had been on a stabilized dose of Testosterone gel for at least 1 month).
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | percentage of subjects |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the percentage of subjects whose maximum observed serum total testosterone concentration (Cmax) fell into one of three stated categories: 1500–1799 ng/dL, 1800–2499 ng/dL, or above 2500 ng/dL. It is a categorical summary of concentration measurements, rather than an average concentration or a comparison of change from baseline. The registered endpoint title groups the categories together, but the registry record does not provide the number or percentage of participants in each category.
Cmax is the highest concentration observed among the scheduled samples. In general, a maximum observed value describes the measurements collected at the specified sampling times; it need not capture the exact biological peak between samples. The schedule included a pre-dose sample and post-dose measurements through 24 hours, with timing tolerances specified for later samples. Measurements were collected between Month 3 and Month 6 after at least one month on a stabilized gel dose.
In general, concentration thresholds can help describe whether measured exposure reaches ranges of interest, while reporting percentages can make the frequency of those categories easier to interpret. The registry says descriptive statistics were used. The reason for selecting these particular thresholds is not reported in the registry record. Without the endpoint counts, percentages, or uncertainty estimates, the frequency and precision of the observed categories cannot be assessed from the registry entry.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted record identifies the question and planned descriptive endpoint, but it does not provide the primary endpoint result. Although the endpoint is defined as the percentage of participants with a maximum observed concentration in one of the specified ranges, no category counts, percentages, confidence intervals, or other uncertainty estimates are reported in the registry record. It is therefore not possible to state how often these concentrations were observed or how precisely their frequency was estimated.
The stated analysis population is per protocol: participants with 24-hour testosterone pharmacokinetic data and no major protocol violations. That definition matters because the enrolled population of 145 is not necessarily the same as the population contributing to the endpoint. The number analyzed is not reported in the registry record. Without that denominator and the outcome counts, neither the endpoint estimate nor its precision can be reconstructed.
The trial’s single-group design also sets an important interpretive boundary. It describes outcomes among participants receiving testosterone gel, but it does not provide a randomized control group for separating treatment-associated observations from other influences. The registry records no masking and allocation as not applicable. The record therefore does not support a comparative estimate of gel versus another treatment.
The primary endpoint description says that descriptive statistics were used. No inferential test or adjusted analysis for the primary endpoint is reported in the registry record. This means the entry does not establish whether a prespecified statistical threshold was met, nor does it provide a basis for claims about statistical significance. The absence of a posted estimate is not evidence that the endpoint was zero or that no participants entered the categories.
Safety information is available in a limited form. The record reports one serious adverse event among 145 at risk and 28 participants with other adverse events among 145 at risk. Dehydration and diverticulitis are listed among the leading serious-event terms, each at 0.7%. A death count is not reported in the registry record. These entries describe reported events in the study group; they do not establish that an event was caused by the gel, and the record does not provide a comparison group for evaluating relative risk.
The registry also lists secondary outcomes involving serum testosterone ranges, questionnaire scores, and hormone exposure. Their outcome values are not reported in the registry record. The study is marked completed, but completion status alone does not supply missing efficacy, pharmacokinetic, or safety estimates. Interpretation should therefore remain limited to the design, endpoint definitions, and adverse-event counts actually recorded.
9. Statistical Methods Explained
The primary endpoint is a percentage: the proportion of an analysis population whose maximum observed serum total testosterone concentration falls within specified categories. The registry describes use of descriptive statistics. It does not report an endpoint estimate or an inferential analysis, so the posted record supports explanation of the measurement and design, but not a conclusion about the frequency of the categories.
What does a percentage endpoint represent?
In general, a percentage expresses how many participants in a defined group meet a stated condition, relative to the group assessed. To interpret one, readers need both the number meeting the condition and the denominator. Here, the condition is a Cmax in one of the listed concentration ranges. The registry gives the per-protocol population definition but does not report how many participants were analyzed or how many met each category. The percentage therefore cannot be verified or interpreted from the posted endpoint entry.
The endpoint title names three concentration ranges. A category-based endpoint groups measurements according to cut points; it does not preserve all the detail in the original continuous concentration values. In general, categorization can make a result easier to summarize, but it also means the category boundaries and the distribution within each category matter. The rationale for these particular boundaries is not reported in the registry record. The record also does not give individual concentration values or a distribution from which the categories could be recreated.
What is maximum observed concentration?
Cmax refers to the highest measured concentration in a sampling profile. In general, an observed maximum depends on when samples are collected, because a peak between scheduled measurements may not be recorded. The registered schedule included a pre-dose sample and post-dose samples at 2, 4, 6, 8, 10, 12, 18, and 24 hours, with stated timing tolerances for the later collection times. Sampling took place between Month 3 and Month 6 after participants had been on a stabilized dose for at least one month. This defines the measurement context, but the record does not report individual profiles or the endpoint results.
The registry states that the data were presented using descriptive statistics. In general, descriptive statistics summarize observed data; they do not by themselves establish that an observed pattern is caused by treatment or differs from a comparator. The record does not identify a hypothesis test, model, or adjusted estimate for this primary endpoint. It also does not report confidence intervals. A confidence interval, in general, describes the uncertainty around an estimate under the assumptions of the method used; without an estimate and interval, the precision of the percentage cannot be judged.
Why does the analysis population matter?
The primary endpoint used a per-protocol analysis population comprising participants with 24-hour testosterone pharmacokinetic data and no major protocol violations. In general, restricting an analysis to participants who meet defined protocol and data requirements can make the analysis focus on participants with the relevant measurements. It can also mean that the analyzed group differs from everyone enrolled. The size of this per-protocol group and the reasons participants may have been excluded are not reported in the registry record. The enrollment count should not be substituted for the missing analysis denominator.
The registry lists 13 outcome measures and zero analyses. It identifies secondary measures involving the percentage of participants within specified testosterone concentration ranges, questionnaire domain scores, and area under the concentration-time curve for total testosterone and dihydrotestosterone. The zero listed analyses does not provide outcome estimates; the registered results entry does not report the endpoint values. Specific missing-data procedures and methods for handling incomplete pharmacokinetic profiles are not reported in the registry record.
What can the design establish?
This is a single-group extension study, with no randomized comparison identified. In general, a control group can provide a concurrent reference for interpreting outcomes, while randomization helps balance groups on measured and unmeasured factors in expectation. Neither a concurrent randomized comparator nor masking is described in this record. The study can describe observations among its participants, but the registered design does not establish a comparative treatment effect.
The record includes a sample-size planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. Such an illustration is a planning calculation, not the trial’s own design justification and not observed power. The registered study itself is single group, so the assumptions described for that illustration do not turn the extension trial into a two-arm randomized comparison. A trial-specific sample-size justification is not reported in the registry record.
Over-dispersion is a general concern for count data when variation exceeds what a simple model assumes; in general, accounting for it can affect standard errors and intervals. The primary endpoint is a percentage derived from categories, and the registry does not report a model, dispersion estimate, or inferential procedure. There is no basis in the record to say whether an over-dispersion adjustment was considered or used.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 13 outcome measures, including the primary testosterone Cmax categories and secondary measures spanning testosterone concentrations, questionnaire domains, and hormone exposure. It lists zero analyses. The results entry does not provide outcome estimates for the primary endpoint or the listed secondary outcomes. A detailed statistical analysis plan, including any approach to multiple testing, is not reported in the registry record.
Multiplicity refers, in general, to the increased chance of obtaining apparently notable findings when many outcomes or tests are examined. Researchers may address this in different ways, such as designating a primary outcome in advance or adjusting interpretation across tests. The record identifies a primary endpoint, but does not describe whether or how multiplicity across the secondary outcomes was handled. It would be inappropriate to assume that an adjustment was made or that none was needed.
The primary analysis population is described as per protocol, requiring 24-hour testosterone pharmacokinetic data and no major protocol violations. The number analyzed, the number missing endpoint data, and reasons for missingness are not reported in the registry record. Specific imputation methods, rules for incomplete sampling profiles, and sensitivity analyses for missing data are also not reported. In general, missingness can affect both the denominator and the interpretation of an estimate; without these details, the direction or extent of any effect cannot be assessed.
The entry does not describe interim analyses or stopping rules. Their presence or absence is not reported in the registry record. The completed status and the stated descriptive approach do not fill those gaps. The record therefore supports a clear description of the planned endpoint and its defined population, but does not provide enough information to assess the full analysis plan, multiplicity control, or missing-data handling.
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 |
|---|---|---|---|
| Testosterone Gel (FE 999303) | 1 | 145 | 0.7% |
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 |
|---|---|
| Testosterone Gel (FE 999303) | 28 of 145 |
Most frequent serious adverse event terms
| Event term | Organ system | Testosterone Gel (FE 999303) |
|---|---|---|
| Dehydration | Metabolism and nutrition disorders | 1 of 145 |
| Diverticulitis | Infections and infestations | 1 of 145 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Testosterone Gel (FE 999303) |
|---|---|---|
| Haematocrit increased | Investigations | 4 of 145 |
| Haemoglobin increased | Investigations | 2 of 145 |
| Hypertonic bladder | Renal and urinary disorders | 2 of 145 |
| Hypertension | Vascular disorders | 2 of 145 |
| Ventricular extrasystoles | Cardiac disorders | 1 of 145 |
| Dyspepsia | Gastrointestinal disorders | 1 of 145 |
| Gastrointestinal haemorrhage | Gastrointestinal disorders | 1 of 145 |
| Gastrooesophageal reflux disease | Gastrointestinal disorders | 1 of 145 |
| Periodontal disease | Gastrointestinal disorders | 1 of 145 |
| Bronchitis | Infections and infestations | 1 of 145 |
Serious events with the highest arm-level rate: dehydration (0.7%), diverticulitis (0.7%).
The adverse-event entry reports one serious adverse event among 145 participants at risk. It also reports other adverse events in 28 participants among 145 at risk. These are counts of participants in the registry’s safety categories, not estimates of the primary testosterone-concentration endpoint. Dehydration and diverticulitis are the listed leading serious-event terms, each reported at 0.7%.
In general, a serious adverse event is a safety classification, while an event term names the reported condition or occurrence. The record does not give a causal assessment for the listed events, so their presence should not be read as proof that the gel caused them. The single-group design also provides no concurrent control group for comparing event frequency with another treatment or with an untreated group.
The death field is not populated with a count; deaths are not reported in the registry record. That is different from a documented count of zero. The entry also does not provide detailed event timing, duration, outcomes, or participant-level links between serious and other adverse events. The reported counts describe the safety information recorded, but do not by themselves establish comparative risk or explain the relationship of any event to treatment.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this was a completed, multicenter, single-group extension trial of testosterone gel in adult hypogonadal males. It defines a primary pharmacokinetic endpoint based on the percentage of participants whose maximum observed serum total testosterone concentration fell within specified high-concentration categories. It also identifies a per-protocol population and a sampling schedule after stabilization on a gel dose.
The record does not report the primary endpoint percentages or category counts. It therefore does not establish how frequently the listed concentration ranges were observed in the analysis population, nor how precisely those frequencies were estimated. No confidence intervals or inferential results for the primary endpoint are reported. The absence of these values cannot be interpreted as evidence that the categories were absent or that a particular threshold was or was not met.
The single-group structure means that observations cannot be compared against a concurrent randomized control group in this trial. In general, outcomes in a treated group may reflect multiple influences; a comparison group and a defined analysis can help distinguish treatment-associated differences from background variation. This record does not provide such a comparison. It consequently cannot establish a comparative treatment effect.
The safety entry provides counts of serious and other adverse events and lists dehydration and diverticulitis among the serious-event terms. Those observations describe reported events, but do not show that the gel caused them. Deaths are not reported in the registry record. The available safety information also does not provide a comparative estimate.
The registry’s definitions are useful for understanding what was intended to be measured, but a defined endpoint is not the same as a reported result. The secondary outcome values, missing-data procedures, multiplicity strategy, and fuller statistical plan are not reported in the registry record. Interpretation should stay within these limits: the design and measurement are described, while the primary outcome magnitude, its uncertainty, and comparative conclusions are unavailable.
13. Why This Trial Matters Statistically
This study illustrates a common distinction in clinical trial interpretation: a registry may describe an endpoint and its measurement in detail without reporting the numerical outcome. The primary measure is clearly framed as the percentage of participants in defined maximum observed testosterone concentration categories, and the record specifies the pharmacokinetic sampling schedule and analysis population. Yet the actual category counts and percentages are not reported in the registry record. Without them, the endpoint’s magnitude and precision cannot be assessed.
The design is also central to statistical interpretation. This is a single-group extension trial, not a randomized comparison. That distinction prevents readers from treating the observed safety counts or concentration measurements as a direct estimate of a difference between treatments. Descriptive observations can characterize participants in the study, but a comparative claim requires a suitable comparator and analysis.
The record also shows why analysis populations and denominators matter. Enrollment was 145, while the endpoint population required complete 24-hour testosterone pharmacokinetic data and no major protocol violations. Since the number analyzed is not reported, enrollment alone cannot determine the denominator for the primary percentage. The same principle applies to safety summaries: counts need to be read alongside the stated at-risk population and the definitions used.
Finally, the entry separates endpoint specification from statistical transparency. It states that descriptive statistics were used, but a detailed analysis plan, missing-data approach, and multiplicity strategy are not reported in the registry record. Recognizing what is defined, what is observed, and what remains unavailable is essential to a disciplined reading of clinical trial evidence.
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 trial’s primary outcome is that the registry defines the endpoint but does not report its numerical result. The category counts, percentages, uncertainty intervals, and number included in the per-protocol analysis are not reported in the registry record. As a result, neither the observed frequency nor its precision can be assessed.
The single-group design offers no randomized concurrent comparator. Allocation is recorded as not applicable and masking as none. This limits interpretation to descriptions of observations among participants and does not support a controlled estimate of a treatment difference. The extension context also means the dose information refers to an earlier study: the dose was fixed on Day 56 of study 000023 and could be down-titrated according to serum testosterone levels at Day 90/91. The registry does not provide the full dose distribution during this extension.
The per-protocol endpoint population excludes participants without 24-hour testosterone pharmacokinetic data or with major protocol violations, but the number excluded and the reasons are not reported. The record does not specify how incomplete sampling, missing measurements, or other missing data were handled. The rationale for the concentration thresholds, endpoint-specific analysis details, and confidence-interval method are also not reported in the registry record.
The registry lists secondary outcomes but does not report their results or a multiplicity strategy. It does not report a detailed sample-size justification, interim-analysis plan, or full statistical analysis plan. The product code differs between the listed intervention, FE 999093, and the adverse-event group, FE 999303. The arm description is also incomplete after its reference to application using an applicator. These gaps should be kept in mind when interpreting the record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Multicenter Extension Trial to Evaluate the Safety of Testosterone Gel — NCT01703741.
- Registry record last updated 2017-10-06; status last verified 2017-09.
- Results first posted 2017-10-06.
- 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
NCT01703741 is a completed Phase 3 multicenter extension trial of testosterone gel in adult males with hypogonadism. Enrollment was 145. The design is listed as single group, with allocation not applicable and no masking. The primary endpoint was the percentage of participants in specified maximum observed serum total testosterone concentration categories, assessed using a per-protocol population after pharmacokinetic sampling on a stabilized dose.
The registry describes descriptive statistics but does not report the primary endpoint counts or percentages, the number analyzed, or uncertainty estimates. Secondary outcome results and a detailed statistical analysis plan are not reported in the registry record. The safety entry records one serious adverse event and other adverse events in 28 participants; deaths are not reported. With no randomized comparator and no posted primary result, the record describes the trial’s design and measures but does not establish a comparative treatment effect.