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 18F-fluciclovine PET in Metastatic Castration Resistant Prostate Cancer Treated With Life Prolonging Therapies (NCT04158245), a na phase 2 study. The primary outcome is Changes in 18F-fluciclovine PET Scan for Patients With mCRPC on Treatment With Life Prolonging Therapies.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT04158245 |
| Phase | Phase 2 |
| Condition | Metastatic Castration-resistant Prostate Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 9 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Tulane University |
| Results posted | Yes |
2. Clinical Question
Population
Men with metastatic castration-resistant prostate cancer (mCRPC). The registry record lists enrollment of 9 participants.
Intervention
The study assessed 18F-fluciclovine PET scans, using a single intravenous administration of 18F-fluciclovine. Participants were to receive an approved life-prolonging therapy: abiraterone with prednisone or dexamethasone, enzalutamide, or docetaxel.
Comparator
There was no concurrent control group. The study is listed as single-group, with allocation recorded as NA and masking as none.
Primary question
How do 18F-fluciclovine PET findings change from before treatment to 12 weeks after starting life-prolonging therapy, using the PERSIST 1.1 response categories?
The central question is descriptive: the study aimed to characterize scan findings at the two stated time points among participants receiving treatment. It was not a randomized comparison of a PET-guided strategy against another strategy, nor a comparison of one life-prolonging therapy with another. The registry record does not report an outcome distribution or an estimate of change. It therefore does not establish how often participants fell into each response category, or how precisely any change was estimated.
3. Trial Design
This was a completed phase 2 pilot study sponsored by Tulane University. The registry record gives a start date of 2020-01-30, a primary completion date of 2022-09-30, and enrollment of 9. Its design is listed as single-group, with allocation NA and no masking. No randomized control arm is described.
The study population was men with metastatic castration-resistant prostate cancer. The planned care included any of the approved life-prolonging therapies named in the record: abiraterone 1000 mg daily with prednisone 5 mg or dexamethasone 0.5 mg daily; enzalutamide 160 mg daily; or docetaxel 50 mg/m2 every two weeks or 75 mg/m2 every three weeks. The registry does not report how participants were selected among these options, how many received each option, or whether treatment choices were balanced across participants.
The PET intervention is described as a single intravenous administration of 18F-fluciclovine for PET scanning. The primary outcome description calls for PET findings before treatment and at 12 weeks after treatment initiation, with metabolic response classified as stable disease, progressive disease, partial response, or complete response under PERSIST 1.1. The record does not describe a protocol for handling missed scans or the exact analysis used to compare the scans. Although the study status is completed, the posted registry record contains no primary-outcome results or statistical analyses.
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 | 18F-fluciclovine PET Scan |
|---|---|
| STARTED | 9 |
| COMPLETED | 8 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | 18F-fluciclovine PET Scan |
|---|---|
| Lost to Follow-up | 1 |
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 | 18F-fluciclovine PET Scan |
|---|---|---|
| Participants analysed | 9 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 |
| Age, Categorical: >=65 years | Participants | 3 |
| Age, Continuous | Years | 62.56 (SD 11.07) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 9 |
| 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 | 4 |
| Race (NIH/OMB): White | Participants | 5 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 9 |
| Haemoglobin | g/dL | 12.23 (SD 1.73) |
| Platelets | cells/mcL | 257.56 (SD 105.58) |
| Calcium | mg/dL | 9.31 (SD 0.50) |
| Creatinine | mg/dL | 1.15 (SD 0.56) |
| Alkaline phosphatase | IU/L | 95.78 (SD 35.82) |
| Prostate-Specific Antigen | ng/mL | 150 (SD 399) |
| Testosterone: Testosterone undetectable | Participants | 8 |
| Testosterone: Testosterone detectable | Participants | 1 |
6. Primary Endpoint
The registry lists the primary outcome as Changes in 18F-fluciclovine PET Scan for Patients With mCRPC on Treatment With Life Prolonging Therapies, measured over 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint concerns participant-level 18F-fluciclovine PET findings before starting life-prolonging therapy and at 12 weeks after treatment initiation. The outcome is described in terms of four metabolic-response categories under PERSIST 1.1: stable disease, progressive disease, partial response, and complete response. The unit is participants, and the stated measure is a count of participants.
A categorical endpoint can describe how many participants are classified in each response state. When observations are collected before and after treatment in the same people, the pattern of movement between categories may also matter: a final category alone does not show whether an individual changed category. The registry record describes assessments at both time points but does not report participant-level transitions, category counts, or an analysis of paired observations.
These scan categories are used to describe metabolic response as defined for the study. They do not, by themselves, report a clinical outcome beyond the scan assessment. The record does not explain how the PET findings were linked to other outcomes or how missing or indeterminate scans would be classified. No primary-endpoint result is reported in the registry record, so the frequency or precision of any response pattern cannot be assessed from the posted results.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes the study question and planned scan assessments, but it does not post results for the primary endpoint. There are no reported participant counts for stable disease, progressive disease, partial response, or complete response, and no reported estimate of change from the pretreatment scan to the scan at 12 weeks. The record lists 0 analyses. The status is completed, but completion status does not supply the missing outcome estimates.
Consequently, the posted results do not show the distribution of PET response categories, the number of participants whose category changed, or the direction of any changes. They also do not report a confidence interval or a statistical test for the primary endpoint. Without those quantities, the size and precision of any observed pattern cannot be judged. This is a limit of what the registry record reports, not evidence that no analysis was performed outside the record.
The design also constrains what can be inferred. With a single group and no concurrent control, a before-and-after description cannot separate a scan pattern occurring over time from a pattern attributable to the therapies. Participants could receive different approved therapies, and the record does not state how many received each one. There is no like-for-like comparison between treatment options, nor a randomized comparison that could support a causal contrast between groups.
The primary assessment time point is 12 weeks. The registry record does not report outcomes at other follow-up times, so it cannot describe how PET categories may have changed beyond that stated assessment. It also does not report information on missing scans, the analysis population, or the handling of participants without both assessments. These omissions matter because the completeness and structure of repeated measurements influence how a change estimate should be interpreted.
The safety counts are separate from the unreported primary endpoint. The record reports 0 participants affected by serious adverse events among 9 at risk, 0 affected by other adverse events among 9 at risk, and 0 deaths. These are registry-reported counts; they do not provide a detailed account of event definitions, timing, or ascertainment. In particular, a zero count in a small pilot record should not be read as a precise estimate of risk.
9. Statistical Methods Explained
The statistical meaning of this study depends first on its design and endpoint. It is a single-group pilot in which the primary description concerns PET categories at baseline and 12 weeks. The endpoint is categorical and measured in participants. The record states that scans were intended before treatment and after treatment initiation, but it does not report the statistical method used to compare those measurements. The distinction between a stated measurement plan and a reported analysis is important: the first describes what the study set out to observe, while the second would show how the collected observations were summarized or tested.
What does a categorical response count describe?
A count in each category describes how many participants were classified in that state. It is not a continuous measurement of the size of a scan change, and a count at the later assessment alone does not identify movement from baseline. For repeated categorical measurements, an analysis may need to preserve the fact that the same participant contributes observations at both time points. General statistical practice distinguishes a marginal summary of each time point from a transition summary that records changes within people. The registry record does not say which form of summary or test was planned or used.
Uncertainty is also important. General statistical explanation: a confidence interval describes a range of values compatible with the observed data under a specified method and its assumptions. In a small study, an estimate can be imprecise, and a confidence interval can be wide. No confidence intervals or primary outcome estimates are reported in the registry record, so no particular uncertainty range can be interpreted. No p-value or inferential test result is posted either. The absence of a reported test result should not be mistaken for evidence that a test was performed and found no difference.
Why does the single-group design matter?
A change between pretreatment and follow-up scans is a within-group observation. General statistical explanation: a concurrent comparison group can help distinguish changes associated with the passage of time or other influences from changes associated with an intervention. Without such a group, this study cannot estimate a treatment contrast against a control condition. The registry record lists no randomized allocation and no comparator arm. The study therefore provides no like-for-like comparison among the listed life-prolonging therapies, and observed scan changes, if reported, would need to be interpreted as descriptive rather than as a controlled treatment effect.
The therapies named in the record are not identical regimens. General statistical explanation: when participants receive different interventions, pooling their results can describe the enrolled group, but it may conceal variation among the treatments. To assess treatment-specific patterns, the number and outcome distribution for each treatment would be needed. Those breakdowns are not reported in the registry record. The record also does not describe how treatment selection was made, so no adjustment strategy or interpretation of treatment-group differences can be inferred.
How should planning calculations be read?
The sample-size planning assumptions describe an illustration based on a stated fraction of the observed effect, a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The planning framework is not the enrolled study design: the trial is listed as single-group and has no randomized comparison. General statistical explanation: a sample-size calculation is conditional on its chosen effect, variability assumptions, significance level, allocation, and analysis method. It estimates a planning requirement under those assumptions; it does not show the probability that this completed study detected an effect. Such planning quantities are not observed power, and they are not study outcomes.
The record does not report the effect estimate used for planning or a study-specific sample-size justification. It also does not report a statistical analysis plan, an interim-analysis plan, or the methods used for missing observations. Those details cannot be reconstructed from the endpoint description. Because the record lists 0 analyses and provides no primary outcome counts, there is no basis for recalculating an outcome estimate or checking an inferential result against a posted sponsor analysis.
What role does over-dispersion play?
General statistical explanation: over-dispersion arises when observed variability in data is greater than a statistical model assumes. If a count or categorical-data model underestimates variability, its standard errors may be too small and its intervals or tests may appear more conclusive than warranted. Whether over-dispersion is relevant depends on the particular model and data structure. The registry record does not identify a model or provide the observations needed to assess it, so no conclusion about over-dispersion can be made for this study.
In general, analysis of a small pilot should emphasize the observed counts and their uncertainty rather than rely on a binary declaration of statistical significance. For this record, even that descriptive interpretation is limited because the primary outcome results are not posted. The study's stated categories and assessment time point explain what it intended to measure, but they do not substitute for the actual counts, estimates, or analysis methods.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 2 outcome measures and 0 analyses. It identifies the primary PET outcome, but does not report results for it or describe the other listed outcome measure. A multiplicity plan—such as how statistical interpretation would account for testing more than one outcome or making multiple comparisons—is not reported in the registry record. General statistical explanation: when multiple outcomes or contrasts are examined, the chance of at least one apparently unusual result can increase, so the prespecified analysis and interpretation plan matter. No such plan can be inferred from the posted results.
Information on missing data is also not reported. The record does not say whether all participants completed both PET assessments, how a missed or unusable scan would be handled, or whether any imputation or sensitivity analysis was used. This is relevant to a before-and-after endpoint because the comparison depends on observations from the same people. The number enrolled does not establish how many contributed complete paired scans.
The analysis population is not described. The record does not state whether the primary analysis would include all enrolled participants, only those who received treatment, or only those with both scans. An interim-analysis plan and a statistical analysis plan are not reported in the registry record. These omissions do not establish that no planning or analysis occurred; they mean the posted record does not provide enough detail to assess those choices. With no outcome counts or analyses posted, multiplicity, missing-data handling, and population definitions cannot be evaluated against an actual result.
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 |
|---|---|---|---|
| 18F-fluciclovine PET Scan | 0 | 9 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| 18F-fluciclovine PET Scan | 0 of 9 |
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 |
|---|---|
| 18F-fluciclovine PET Scan | 0 of 9 |
The registry record reports 0 participants affected by serious adverse events among 9 at risk in the 18F-fluciclovine PET Scan group. It also reports 0 participants affected by other adverse events among 9 at risk, and 0 deaths. These are the posted counts; no serious adverse event terms are listed.
These figures should be read as counts in the registry record, not as evidence that the study established the absence of safety concerns. The record does not provide event definitions, the observation period for adverse events, detailed ascertainment procedures, or information about events by life-prolonging therapy. It does not clarify whether adverse events were attributed to the PET procedure, the therapies, or another cause. Therefore, the counts cannot be used to compare safety between therapies or to estimate how frequently events might occur in a broader population.
General statistical explanation: zero observed events in a small group still leaves uncertainty about the underlying event rate. The counts describe what the record reports for this study, while the limited enrollment and absent event details constrain interpretation. No medical conclusion about safety should be drawn from these registry counts alone.
12. What the Result Does, and Does Not, Mean
The study addresses a focused imaging question: how 18F-fluciclovine PET findings are described before life-prolonging therapy and at 12 weeks after its initiation in men with metastatic castration-resistant prostate cancer. Its primary endpoint uses four PERSIST 1.1 categories. The registry record also identifies the study as a phase 2 pilot and reports enrollment of 9.
What the posted results do not provide is the information needed to answer the primary question quantitatively. There are no reported counts in the response categories, no account of how participants moved between categories, and no estimate of the magnitude or uncertainty of change. The record lists 0 analyses. The study is marked completed, but a completed status is not itself an outcome finding.
The single-group design also means the study does not estimate a controlled effect of treatment on PET findings. The record describes several possible life-prolonging regimens, but gives no treatment-specific enrollment or outcomes. It therefore cannot compare those regimens, and it cannot distinguish observed temporal patterns from other influences in the absence of a concurrent control group. The intended scan comparison is descriptive in design, not a randomized treatment comparison.
The record's safety counts are limited to the posted affected-participant counts and deaths. They do not establish the absence of risk or provide comparative safety evidence. Missing information about event definitions and timing further limits interpretation.
Statistically, the record documents the question, population, design, endpoint categories, and intended assessment time point, but not the primary result or its precision. The result does not show that PET findings changed, remained stable, or followed any particular pattern. It also does not show that there was no change. Those conclusions require outcome data that are not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the distinction between a clearly described measurement question and a reported result. The registry record identifies the population, a single-group phase 2 pilot design, a pretreatment and 12-week PET assessment, and the response categories. Yet it reports no primary outcome counts or analyses. Readers can understand what was intended to be measured without being able to estimate what was observed.
The design makes the limits of comparison especially important. A single group receiving one of several approved therapies can support a descriptive account of scan findings if those findings are reported. It cannot provide a randomized contrast against a control condition, and the record does not give treatment-specific results. Recognizing this distinction prevents an uncontrolled before-and-after observation from being read as a causal estimate.
The small pilot enrollment also places emphasis on transparent reporting of the data structure and uncertainty. For a categorical endpoint measured at two time points, participant-level transitions and the number with both scans would help readers understand the evidence. The registry record does not report those details. General statistical principle: estimates, uncertainty intervals, and explicit analysis methods are needed to assess both the size and reliability of a finding; a study label or completion status cannot substitute for them.
The planning assumptions illustrate another useful distinction. A sample-size illustration based on two-arm equal allocation is a planning exercise, not a description of this single-group trial and not observed power. Statistical interpretation depends on matching assumptions to the actual design. In this record, the mismatch is a reason to keep planning calculations separate from conclusions about the enrolled study.
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 most direct limitation is that the registry record does not report primary-outcome results. Although the study is marked completed, there are no category counts, estimates of change, confidence intervals, or statistical analyses posted. The intended PET assessments therefore cannot be used to characterize an observed response pattern from this record.
Enrollment was 9, and the study was a single-group pilot with no concurrent control. It cannot estimate a randomized treatment contrast or establish that any observed scan change was caused by treatment. The record describes several possible life-prolonging regimens but does not report how many participants received each regimen or provide therapy-specific outcomes. Differences across those treatment experiences cannot be assessed.
The endpoint description specifies baseline and 12-week assessments, but the record does not report whether all participants completed both scans, how missing or indeterminate assessments were handled, or which analysis population was used. It also does not report the statistical analysis plan, multiplicity approach, or interim analyses. Those omissions prevent assessment of whether the intended analysis and the reported results align, and no results are available to evaluate in any case.
The primary follow-up point described is 12 weeks. The registry record does not report longer-term scan findings or other follow-up results. The safety information is limited to affected-participant counts and deaths, without event definitions, timing, attribution, or treatment-specific detail. These are limitations of the available registry record and should not be replaced by assumptions about what may have been collected or analyzed elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: 18F-fluciclovine PET in Metastatic Castration Resistant Prostate Cancer Treated With Life Prolonging Therapies — NCT04158245.
- Registry record last updated 2025-09-22; status last verified 2025-02.
- Results first posted 2025-09-22.
- 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
NCT04158245 is a completed phase 2, single-group pilot sponsored by Tulane University. It enrolled 9 men with metastatic castration-resistant prostate cancer and assessed 18F-fluciclovine PET findings before treatment and at 12 weeks after initiation of a life-prolonging therapy. The study description lists abiraterone, enzalutamide, or docetaxel as treatment options and defines the primary PET response categories under PERSIST 1.1.
The registry record reports 0 analyses and does not report primary outcome counts or estimates. It reports 0 participants affected by serious adverse events among 9 at risk, 0 affected by other adverse events among 9 at risk, and 0 deaths. Missing-data procedures, analysis populations, and a multiplicity plan are not reported in the registry record. The single-group design does not provide a randomized comparator.