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 Enzalutamide in Patients With High-risk Prostate Cancer (NCT01927627), a na phase 2 study. The primary outcome is To Evaluate the Clinical Efficacy of Enzalutamide.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01927627 |
| Phase | Phase 2 |
| Condition | Adenocarcinoma of the Prostate |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 42 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Case Comprehensive Cancer Center |
| Results posted | Yes |
2. Clinical Question
Population
Patients with high-risk prostate cancer who had undergone local definitive therapy with radical prostatectomy. The primary-outcome population is described more narrowly as participants who received treatment and had biochemical recurrence; the registry record does not explain further how that population was selected for the reported measure.
Intervention
Oral enzalutamide, described as 160mg (4 capsules) once daily. The study evaluated treatment after surgery.
Comparator
No concurrent comparator is reported. The study is listed as single-group, with no allocation, and does not provide a like-for-like control arm.
Primary question
How long until biochemical recurrence, as defined by the study, among the relevant participants receiving enzalutamide after surgery? Although the primary outcome is named as an evaluation of clinical efficacy, the registry record does not report the measured median or its range.
The clinical question concerns recurrence after definitive local treatment, rather than a comparison between enzalutamide and another treatment. The registry describes a phase two study of enzalutamide in patients with high-risk prostate cancer who had undergone radical prostatectomy. Its brief description frames the question as whether cancer returns during treatment, while the primary outcome operationalizes recurrence using prostate-specific antigen findings or a subsequent treatment decision.
That operational definition matters: biochemical recurrence is a laboratory- and treatment-based endpoint, not a direct report of symptoms, metastasis, or survival. The record does not report those outcomes as the primary endpoint. Safety is listed as a secondary outcome, but detailed definitions for the safety measures are not reported in the registry record.
Because there is no concurrent control group, the study can describe observations among treated participants but cannot establish a comparative treatment effect against an untreated or differently treated group. The registry record also does not report a primary endpoint result, so the duration observed before recurrence cannot be characterized from the posted information.
3. Trial Design
This is a phase two, single-group study sponsored by Case Comprehensive Cancer Center. The registry lists an enrollment of 42 and describes the participants as having high-risk prostate cancer after radical prostatectomy. The study began on 2013-11-11, reached primary completion on 2017-03-29, and is listed as completed. These dates describe the registry record; they do not provide the duration of treatment or follow-up for any individual participant.
The listed intervention was oral enzalutamide at 160mg (4 capsules) once daily. Masking is listed as none. Allocation is listed as not applicable, consistent with the single-group model. There is no concurrent control arm in the record, so the study is not a randomized comparison and its participants cannot be contrasted with a like-for-like control group within this trial.
The primary outcome is described as median time to disease progression, with biochemical recurrence as the definition of progression and months as the unit. The timeframe is 2 years. The specified outcome population is participants who received treatment and had biochemical recurrence. The registry record does not report the outcome value or full range, nor does it give further detail on how follow-up was handled for participants who did not have recurrence.
Safety of enzalutamide is listed as a secondary outcome. The record lists 3 outcome measures, but descriptions of the other measures beyond the named primary and secondary outcomes are not reported in the registry record. The record lists no analyses. Protocol details such as the statistical plan, sample-size justification, interim analyses, and analysis timing are not reported in the registry record. Completion status alone does not establish that all planned analyses or outcome results were posted.
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 | Enzalutamide |
|---|---|
| STARTED | 42 |
| COMPLETED | 37 |
| NOT COMPLETED | 5 |
Reasons for not completing this period:
| Reason | Enzalutamide |
|---|---|
| Adverse Event | 3 |
| Lack of Efficacy | 1 |
| Financial Concerns | 1 |
Analysis population for the primary outcome, as defined in the registry: All participants who received treatment and had biochemical recurrence.
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 | Enzalutamide |
|---|---|---|
| Participants analysed | 42 | |
| Age, Continuous | years | 59 (43 to 70) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 42 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 0 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 42 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 42 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 42 |
6. Primary Endpoint
The registry lists the primary outcome as To Evaluate the Clinical Efficacy of Enzalutamide, measured over 2 years.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
The primary endpoint measures time to disease progression, defined in this study as biochemical recurrence. Recurrence was defined as a prostate-specific antigen level of at least 0.2ng/mL on 2 consecutive laboratory results, or any rise in prostate-specific antigen that resulted in subsequent therapy. The measure is expressed as a median in months, with a full range, and has a stated timeframe of 2 years.
Time-to-event endpoints are generally used when the timing of an event is important and participants may experience that event at different points during follow-up. A median can describe the middle of the observed event-time distribution for the population analyzed. A full range can indicate the span of observed values, but by itself does not show how observations are distributed within that span or how precisely the median is estimated. A confidence interval, when reported, would help express uncertainty around an estimate; one is not reported for this endpoint in the registry record.
The endpoint is biochemical rather than a direct measure of symptoms, quality of life, metastatic disease, or death. The registry definition also includes a treatment decision triggered by a PSA rise. Those criteria make the endpoint clinically interpretable within the study's stated framework, but they do not make it interchangeable with other outcomes.
The record names the measure and its definition but does not report the median or full range. It also defines the outcome population as participants who received treatment and had biochemical recurrence. Without the result and fuller information about the analysis population and follow-up, the endpoint cannot be used to characterize the observed time to recurrence for all enrolled participants.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a single-group study of enzalutamide after radical prostatectomy, with time to biochemical recurrence as the primary endpoint. The posted information includes the endpoint definition and safety counts, but not a numerical primary endpoint result. No median time, full range, confidence interval, or sponsor-reported hazard ratio is reported in the registry record. Consequently, the size and precision of the primary outcome cannot be assessed from this record.
The outcome population is described as participants who received treatment and had biochemical recurrence. This differs from a description of all enrolled participants, and the record does not explain how participants without recurrence contribute to the time-to-event measure. In general, time-to-event analyses can include participants who have not yet experienced the event by the end of observation as censored observations. Whether and how that approach was used in this study is not reported in the registry record. The stated population therefore deserves attention when interpreting any result, but the posted record does not provide enough detail to reconstruct the analysis.
The study has no concurrent comparator. Its observations can describe what was recorded for participants in the enzalutamide group, but a single-group design cannot separate treatment-associated outcomes from other explanations, including the natural course after surgery, differences in follow-up, or participant selection. Those are general limitations of uncontrolled comparisons, not findings about what happened to individuals in this study.
The safety information lists serious adverse events in the enzalutamide group and reports 0 deaths. It also lists other adverse events. These are counts recorded in the registry; they do not establish that enzalutamide caused any event or that an event was absent outside the reporting scope. The registry does not provide further event definitions or individual-level timing in the registry record.
Any planning illustration based on an observed effect would be hypothetical rather than an observed power calculation. Planning values depend on assumptions about the effect to detect and the analysis design, and cannot substitute for the missing endpoint estimate or its uncertainty. The registry does not report the study's own sample-size rationale or full statistical analysis plan.
The appropriate statistical conclusion is therefore limited: the record identifies the study question, design, endpoint definition, and selected safety counts, but does not report the primary efficacy result needed to judge its magnitude or precision. No treatment-effect claim follows from the available information.
9. Statistical Methods Explained
The endpoint is a time-to-event measure. In general, such methods use both whether an event was observed and when it occurred. They are useful when follow-up time can vary, because a participant who has not experienced the event by the last observation may still contribute information up to that point. This situation is often handled through censoring. The registry record does not describe whether censoring was used, how follow-up ended for each participant, or which estimator generated the reported median.
What does a median time represent?
As a general statistical concept, a median is the point that divides an ordered distribution into two equal parts. For time-to-event data, it refers to the event-time distribution estimated for the population and analysis being considered. It is not an average, and it does not mean that each participant experienced the event at that time. A median needs to be interpreted alongside its population, follow-up, and uncertainty. The registry identifies the endpoint as a median in months but does not report its value or a confidence interval.
The stated event is biochemical recurrence, not every possible form of disease progression. The definition combines a PSA threshold on consecutive laboratory results with a PSA rise leading to subsequent therapy. In general, composite definitions can capture more than one route to an event, but the components may have different meanings. The registry record does not state how many events met each part of the definition, so those components cannot be evaluated separately.
Why does a confidence interval matter?
In general, a confidence interval describes the uncertainty associated with an estimate under the assumptions of the statistical method. It is not a range that guarantees where the true value lies, nor does it describe the range of individual participant outcomes. For a median time-to-event estimate, an interval would show how precisely the median is estimated. No interval for the primary endpoint is reported in the registry record, so precision cannot be judged from the posted primary outcome information.
Hazard ratios are another common time-to-event statistic. In general, a hazard ratio compares event rates over time between groups, subject to the model and assumptions used. It is inherently comparative and requires an appropriate contrast. This study is listed as single-group and does not report a control arm; a treatment-versus-control hazard ratio is therefore not available in the registry record. A hazard ratio should not be inferred from the median or from the study design.
What does the single-group design allow?
General statistical interpretation distinguishes description from causal comparison. A single-group result can describe outcomes observed under the study conditions. Without a concurrent comparator, it cannot isolate the contribution of the intervention from other influences. Even a precisely estimated time-to-event outcome would not, on its own, establish what would have happened to the same participants under another treatment or no treatment.
Allocation is listed as not applicable, masking as none, and the model as single-group. These design features mean there is no randomized allocation between study arms to support a randomized contrast. They do not reveal how participants were recruited, how adherence was assessed, or how outcome assessment was conducted; those details are not reported in the registry record.
How should planning illustrations be understood?
In general, sample-size planning asks how much information a future study might need to detect a prespecified effect under stated assumptions. An illustration based on a fraction of an observed effect explores hypothetical planning scenarios; it does not describe the number of participants actually analyzed, establish the study's original design rationale, or measure observed power. The registry record says that its planning assumptions use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with time-to-event planning expressed as a total number of events. Those are planning assumptions, not the design of this single-group study. Its original sample-size justification is not reported in the registry record.
Observed power is generally not a useful substitute for an effect estimate and its confidence interval: it is tied to the observed data and does not resolve uncertainty about the effect. Since the primary outcome value is absent, planning illustrations cannot fill that gap. They should be read as hypothetical design calculations rather than evidence about the study's result.
What can the posted record support?
The record supports a description of the study design, intervention, endpoint definition, timeframe, and selected safety counts. It does not support a recalculation of the primary endpoint, because the required result and supporting summary statistics are not reported. The record lists no analyses, and detailed methods for the primary outcome, missing observations, and analysis population are not reported in the registry record. A statistical interpretation should preserve these distinctions rather than infer an analysis from the endpoint label alone.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity concerns the interpretation of statistical testing when a study examines multiple endpoints, comparisons, or analysis opportunities. In general, testing multiple hypotheses can increase the chance of a nominally unusual result unless the analysis plan accounts for that structure. The registry record lists 3 outcome measures and identifies safety as a secondary outcome, but does not report a multiplicity strategy, a hierarchy of tests, or whether formal hypothesis tests were conducted. The record lists no analyses. It is therefore not possible to determine how multiplicity was addressed or whether it affected any reported inference.
Missing-data methods matter because participants may have incomplete follow-up, incomplete endpoint measurements, or an unknown event status at the end of observation. For time-to-event outcomes, censoring is often used for observations that end before an event is documented; other kinds of missingness may require different treatment. These are general considerations. The registry record does not report the amount or pattern of missing data, reasons for missingness, censoring rules, or sensitivity analyses.
The primary-outcome population is described as all participants who received treatment and had biochemical recurrence. The record does not explain whether this describes the analysis set, how participants without recurrence were handled, or whether every enrolled participant received treatment. It also does not report a population definition such as intention-to-treat. Those details are not reported in the registry record and should not be inferred from enrollment or completion status.
Because there is no reported primary result or analysis description, readers cannot assess whether exclusions, missing observations, or multiple outcome analyses changed the estimate. The appropriate interpretation is that these analytic details remain unspecified 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 |
|---|---|---|---|
| Enzalutamide | 2 | 42 | 4.8% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Enzalutamide | 0 of 42 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Enzalutamide | 41 of 42 |
Most frequent serious adverse event terms
| Event term | Organ system | Enzalutamide |
|---|---|---|
| Abducens nerve disorder | Nervous system disorders | 1 of 42 |
| Bone infection | Infections and infestations | 1 of 42 |
| Thromboembolic event | Vascular disorders | 1 of 42 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Enzalutamide |
|---|---|---|
| Fatigue | General disorders | 37 of 42 |
| Gynecomastia | Reproductive system and breast disorders | 31 of 42 |
| Pain | General disorders | 27 of 42 |
| Weight gain | Investigations | 20 of 42 |
| Hyperglycemia | Metabolism and nutrition disorders | 17 of 42 |
| Breast pain | Reproductive system and breast disorders | 16 of 42 |
| Alopecia | Skin and subcutaneous tissue disorders | 15 of 42 |
| Diarrhea | Gastrointestinal disorders | 11 of 42 |
| Weight loss | Investigations | 11 of 42 |
| Arthralgia | Musculoskeletal and connective tissue disorders | 10 of 42 |
Serious events with the highest arm-level rate: abducens nerve disorder (2.4%), bone infection (2.4%), thromboembolic event (2.4%).
The registry lists the enzalutamide group with 42 participants at risk for serious adverse events and 2 affected. It lists 42 at risk for other adverse events and 41 affected, and reports 0 deaths. These counts describe the posted safety record; they should be read separately from the efficacy endpoint.
The listed serious-event terms are abducens nerve disorder, bone infection, and thromboembolic event, each reported as 2.4%. The registry does not provide further detail about event timing, severity grading, recurrence, or the relationship of each event to treatment. The term “at risk” is used in the registry counts, but the record does not explain the specific safety-analysis rules behind that denominator.
Counts of participants with events do not by themselves establish causation. They also do not indicate how long each participant was observed or whether all events were captured in the same way. The “other adverse events” count is a separate registry category, and the record does not give its detailed event list in the registry record. A count of 0 deaths is a report for this study record, not proof that an event could never occur.
The safety figures should therefore be treated as descriptive counts. They do not provide a comparative risk estimate, since there is no control group, and the registry record does not include the detail needed for a fuller safety assessment.
12. What the Result Does, and Does Not, Mean
The study addresses a specific statistical question: the time to a registry-defined biochemical recurrence among participants treated with enzalutamide after radical prostatectomy. The record gives the intervention and outcome definition, but not the primary endpoint estimate. It therefore does not show the median time to recurrence, the full range, or the precision of that estimate.
Even if a median were reported, its meaning would depend on the population included in the analysis, follow-up, and handling of participants without a documented event. The registry describes the outcome population as participants who received treatment and had biochemical recurrence, but does not clarify how this description relates to the full enrolled group. The result cannot be extended to all enrolled participants without that information.
The design also constrains interpretation. A single-group study has no concurrent control against which to compare outcomes. It can describe observations within the treated group, but cannot show how outcomes would have differed under an alternative. This distinction is central: a treatment effect is a contrast, and the record does not supply a comparative estimate.
The safety counts describe events recorded in the registry. They do not prove that enzalutamide caused an event, and they do not establish the absence of risks not captured by the reported counts. The listed event percentages are descriptive, not comparative estimates.
Accordingly, the posted record supports statements about the planned clinical question, study structure, endpoint definition, and selected safety observations. It does not support a conclusion about the size or precision of an efficacy result, or a causal claim that the intervention changed recurrence. Those conclusions would require outcome results and analytic details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This study illustrates how an endpoint definition shapes the statistical question. Here, progression is operationalized as biochemical recurrence using PSA results or a subsequent treatment decision. That definition is more specific than a broad label such as disease progression, and its components determine what counts as an event. A reader should therefore distinguish the study's defined endpoint from other possible measures of disease status.
It also demonstrates why the analysis population matters. The registry describes the primary-outcome population as participants who received treatment and had recurrence, while the enrolled group is described separately. Without a clear account of who contributed to the time-to-event estimate and how participants without an event were handled, the scope of any result would be difficult to interpret.
The single-group design is statistically important because it supports description, not a randomized comparison. That limitation is separate from the precision of any estimate: a result can be measured with precision within one group without identifying a causal effect relative to another treatment. The absence of a reported endpoint value adds a further limitation, preventing assessment of even the descriptive result's magnitude and uncertainty.
Finally, the safety record highlights the distinction between event counts and comparative risk. Counts can convey what was recorded, while causal and comparative conclusions require appropriate design and more detailed analysis. In this study, the registry record gives selected safety counts but does not report the supporting detail needed to interpret them beyond description.
These features make the record useful for understanding the question and design, while also showing why endpoint results, analysis populations, uncertainty estimates, and a suitable comparator are essential to statistical interpretation.
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 interpreting this trial from the registry record is that the primary endpoint result is not reported. The record names a median time-to-event measure and a full range, but gives neither value. It also does not report a confidence interval or a sponsor-reported hazard ratio. The magnitude and precision of the primary result therefore cannot be evaluated.
The study is single-group, with no concurrent comparator. This prevents a within-trial comparative estimate and limits causal interpretation, even if descriptive outcomes were available. Masking is listed as none. The registry record does not describe outcome-assessment procedures, adherence, treatment duration, participant recruitment, or follow-up schedules, so their possible influence cannot be assessed.
The stated outcome population—participants who received treatment and had biochemical recurrence—requires clarification for interpretation. The registry does not explain how participants without recurrence were included or handled, whether all enrolled participants received treatment, or how censoring and missing outcome information were addressed. These analysis details are not reported in the registry record.
The safety information is also limited to selected counts and listed serious-event terms. Further definitions, timing, attribution, and detailed event data are not reported in the registry record. No detailed statistical analysis plan, sample-size justification, interim-analysis information, or multiplicity strategy is reported either. These limitations are specific to the information available for this study and constrain conclusions about both the efficacy endpoint and safety findings.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Enzalutamide in Patients With High-risk Prostate Cancer — NCT01927627.
- Registry record last updated 2019-03-20; status last verified 2019-03.
- Results first posted 2019-03-12.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry describes a completed phase two, single-group study of oral enzalutamide after radical prostatectomy in patients with high-risk prostate cancer. Enrollment is listed as 42. The intervention is described as 160mg (4 capsules) once daily, and masking is listed as none.
The primary outcome is median time to biochemical recurrence, measured in months, with a 2 years timeframe. Recurrence is defined by PSA results or a PSA rise leading to subsequent therapy. The registry record does not report the median, full range, confidence interval, or a hazard-ratio result.
Safety is listed as a secondary outcome. The record reports 2 participants with serious adverse events, 41 with other adverse events, and 0 deaths, alongside the listed serious-event terms. No concurrent comparator is reported. Detailed analysis methods, missing-data handling, and the study's sample-size justification are not reported in the registry record.