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 Cabozantinib-S-Malate in Treating Patients With Hormone-Resistant Metastatic Prostate Cancer (NCT01812668), a na na study. The primary outcome is Change in PET Standard Uptake Value SUV Levels Pre-treatment to Post-treatment..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01812668 |
| Phase | NA |
| Condition | Adenocarcinoma of the Prostate, Hormone-resistant Prostate Cancer, Recurrent Prostate Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 20 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Barbara Ann Karmanos Cancer Institute |
| Results posted | Yes |
2. Clinical Question
Population
Patients with hormone-resistant metastatic prostate cancer. The registry lists adenocarcinoma, recurrent prostate cancer and stage IV prostate cancer among the conditions.
Intervention
Cabozantinib-s-malate taken orally each day in the absence of disease progression or unacceptable toxicity. PET imaging, fluorine F 18 d-FMAU, pharmacological study and laboratory biomarker analysis are also listed.
Comparator
There was no separate comparator group. The study is recorded as a single-group trial, with no allocation to a control arm.
Primary question
What was the percentage change in PET standard uptake value from baseline to 4 weeks after treatment began?
The trial’s stated purpose was to explore changes in bone- and tumor-imaging-related pathways in patients receiving cabozantinib-s-malate. The primary endpoint concerns change in PET standard uptake value (SUV), a measurement recorded in g/ml. The percentage change was defined as the post-treatment value minus the pre-treatment value, divided by the pre-treatment value, then multiplied by 100.
This is a question about change over time within the treated group, not a comparison of treatment with an untreated or alternative-treatment group. Without a comparator, the trial cannot separate changes associated with treatment from changes that might occur over time for other reasons. The registry record also lists secondary outcomes concerning progression, toxicity, clinical response, PSA response and PET response. It does not report the observed primary-endpoint result or the outcome-specific results needed to describe those questions.
3. Trial Design
This was a completed, single-group pilot trial sponsored by Barbara Ann Karmanos Cancer Institute. The registry lists enrollment of 20 and gives the study phase as NA. It records no allocation and no masking. The study started in 2013-03, had primary completion on 2019-01-18, and is marked completed.
Participants received oral cabozantinib-s-malate daily in the absence of disease progression or unacceptable toxicity. The registry also lists fluorine F 18 d-FMAU, positron emission tomography, pharmacological study and laboratory biomarker analysis as interventions. These listings describe study procedures and analyses, but the registry record does not provide enough detail to reconstruct when or how each was performed.
The primary outcome was the change in PET SUV from baseline to 4 weeks, expressed as percentage change from baseline. The registered summary statistic is the median, with the full range as the dispersion measure. The registry lists six outcome measures, including time to progression, toxicities of Grade 3 or higher, and clinical, PSA and PET response measures based on RECIST Criteria 1.1.
A single-group design can describe measurements and events among participants receiving the study regimen. It does not provide a concurrent comparison with another treatment or with no treatment. As a result, observed changes cannot by themselves establish what would have happened to similar patients under a different treatment strategy. The registry record does not report a detailed statistical analysis plan, a sample-size justification, or methods for handling incomplete observations.
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 | Treatment (Cabozantinib-s-malate) |
|---|---|
| STARTED | 20 |
| COMPLETED | 20 |
| NOT COMPLETED | 0 |
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 | Treatment (Cabozantinib-s-malate) |
|---|---|---|
| Participants analysed | 20 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 |
| Age, Categorical: >=65 years | Participants | 14 |
| Age, Continuous | years | 69 (56 to 76) |
| Sex: Female, Male: Female | Participants | 0 |
| Sex: Female, Male: Male | Participants | 20 |
| 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 | 5 |
| Race (NIH/OMB): White | Participants | 15 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 20 |
6. Primary Endpoint
The registry lists the primary outcome as Change in PET Standard Uptake Value SUV Levels Pre-treatment to Post-treatment., measured over Baseline to 4 weeks.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | Full Range |
| Unit | percentage change from baseline |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the percentage change in PET standard uptake value from baseline to 4 weeks. SUV is a PET measurement expressed in g/ml. The registered calculation compares a post-treatment measurement with its pretreatment value: post-treatment minus pre-treatment, divided by pre-treatment, then multiplied by 100. The registry specifies the median as the summary statistic and the full range as the measure of dispersion.
In general, a percentage change expresses an individual’s change relative to that individual’s starting measurement. A negative value under the registered formula would indicate a lower post-treatment SUV than pretreatment SUV; a positive value would indicate a higher value. This is a general interpretation of the formula, not a statement about the trial’s observed result. The registry record does not report the median change or its range.
PET measurements were relevant to the trial’s stated aim of exploring imaging-related pathways in bone and tumor. A measurement at a defined time after baseline gives a way to describe imaging change over that interval. It is not, on its own, a direct measure of how long participants live, how they feel, or whether the treatment caused the change. The record does not report a validation of SUV change as a surrogate for those outcomes. Interpretation also depends on the measurement and analysis procedures, which are not described in sufficient detail in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registered primary question concerns within-group change in PET SUV between baseline and 4 weeks. Although the registry identifies the endpoint, summary statistic and dispersion measure, it does not report the observed median percentage change, the full range, or an uncertainty interval. Consequently, the size and precision of the primary outcome cannot be described from the registry record.
The study enrolled 20 participants and used a single-group design. That design can document what was observed among the participants who received cabozantinib-s-malate, but it cannot estimate a treatment contrast against a concurrent control group. A change from baseline may reflect treatment, the natural course of disease, measurement variability, other care, or a combination of influences. Without a comparator and an appropriate analysis, those explanations cannot be distinguished.
The registry lists several secondary outcomes, including time to progression, toxicities of Grade 3 or higher, and response measures. The existence of registered outcomes does not establish that results were reported for them. Outcome-specific numerical findings and analyses are not reported in the registry record. The record also does not give confidence intervals or other estimates of uncertainty for the primary endpoint.
For safety, the registry records serious adverse events affecting 4 participants in the treatment group and other adverse events affecting 20 participants. It lists 18 deaths. These counts should be read as registry safety entries, not as evidence that the study drug caused the events or deaths. The record does not provide the timing, causes, or attribution needed to interpret them in relation to treatment. It lists hand foot syndrome, fatigue, urinary infection and elevated creatinine among the serious-event terms, each with a recorded percentage of 5.0%.
The record’s reported enrollment and its safety entries are not a substitute for an analysis population description. The number of participants with primary-endpoint measurements, the number included in each outcome analysis, and the handling of missing measurements are not reported in the registry record. Without those details, the extent to which outcome summaries represent all enrolled participants is unclear.
Overall, the record describes a pilot study and the question it set out to examine, but it does not provide the primary outcome estimate needed to judge the observed imaging change. Even with a reported change, a single-group result would remain descriptive and would not establish a causal treatment effect.
9. Statistical Methods Explained
The registry characterizes this study as a single-group trial with no allocation and no masking. The primary outcome is a change from baseline, summarized by the median and full range. No primary outcome estimate, confidence interval, or detailed analysis method is reported in the registry record. The explanations below describe general statistical ideas relevant to these design features; they are not claims about methods the investigators used.
What does a single-group design estimate?
In general, a single-group study describes outcomes observed among people who receive the study intervention. When a measurement is taken before and after treatment, an analysis can describe the change within that group. A treatment effect, however, is a contrast between outcomes under different treatment conditions. Without a concurrent comparison group, the observed before-and-after change does not show what would have occurred over the same period without the intervention or under another intervention.
Changes may arise for multiple reasons. Disease can change over time, measurements can vary, and other aspects of care can affect outcomes. Randomized allocation can help make groups comparable on average, but this trial has no randomized comparison according to the registry. Statistical adjustment cannot guarantee removal of all differences or sources of bias, particularly when important variables are unmeasured or not reported.
Why use the median and full range?
In general, the median is the central value after observations are ordered. Unlike the mean, it is less influenced by unusually high or low observations. The full range reports the smallest and largest observed values, showing the span of the data, but it does not describe how densely observations cluster between those endpoints. A range can also be sensitive to extreme observations.
These summaries may be useful for a pilot endpoint when the distribution is uncertain or observations vary substantially. They do not, by themselves, quantify how precisely the population’s typical change has been estimated. A confidence interval can express uncertainty around an estimate; its interpretation depends on the method and assumptions used to calculate it. No confidence interval for the primary endpoint is reported in the registry record.
How should percentage change be understood?
General explanation: percentage change places an observed difference in relation to the baseline value. This can make changes easier to compare across different starting levels, but it also means the result depends on the baseline measurement. If baseline values are small, measurement variation can have a larger influence on a percentage change. The registry defines the formula but does not report the individual baseline values or the observed changes needed to assess this issue in the trial.
A change score also carries uncertainty from both measurements: the baseline value and the later value. Measurement error at either time can affect the calculated change. Interpretation therefore depends on consistent imaging and measurement procedures. Details about such procedures, including the full acquisition and reading process, are not reported in the registry record.
What would a confidence interval add?
General explanation: a confidence interval gives a range of values compatible with the observed data under a statistical method and its assumptions. A narrow interval indicates greater precision than a wide interval, but neither width nor interval location establishes that a treatment caused an outcome. In a single-group study, an interval around change would describe uncertainty in that group’s change estimate; it would not create a missing control comparison.
The registry record does not report a confidence interval for the primary endpoint. Nor does it describe a statistical test or provide an analysis estimate for that outcome. The median and full-range specification therefore does not allow the precision of the primary result to be assessed.
What do the planning illustrations mean?
General explanation: sample-size calculations are planning tools that show how many participants a future comparison might require under chosen assumptions. The record describes planning illustrations based on a fraction of the observed effect, with two-sided significance level 0.05, equal allocation and a normal approximation. These are not the trial’s own design justification and are not observed power. They should not be read as evidence that the study had a particular probability of detecting an effect. The record does not report a prospective sample-size justification for this pilot.
In general, a planning calculation depends on the effect chosen for detection, variability assumptions, statistical error rates and design. Changing those assumptions changes the planning result. Using an effect estimated from a small pilot can produce an unstable basis for planning, because the observed effect itself may be imprecise. The registry record does not supply enough detail to assess the reliability of any such estimate or to identify a confirmed statistical analysis plan for the trial.
What does missing analysis information prevent?
General explanation: readers need to know which participants contributed data to each analysis, how missing measurements were handled, and whether analyses followed a prespecified plan. These details help assess selection bias and whether the reported estimate answers the registered question. The registry record does not report the primary-endpoint analysis population, missing-data method, or statistical analysis plan. It lists zero analysis records, so no outcome analysis method or estimate is available in that registry component.
These omissions do not establish that no analyses were conducted. They mean that the analyses and their assumptions are not reported in the registry record and cannot be evaluated from the record alone.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists six outcome measures, covering imaging change, progression, toxicities and response measures. When a study assesses multiple outcomes, general statistical practice distinguishes a prespecified primary question from additional questions. If many statistical tests are conducted, the chance of at least one apparently unusual result can increase. A multiplicity plan may specify which outcomes are confirmatory, whether tests are adjusted, and how results should be interpreted. The registry record does not report such a plan or any multiplicity adjustment.
The registry identifies the PET SUV change as the primary outcome, but it does not report an analysis of that outcome. It also does not provide outcome-specific analysis methods for the listed secondary outcomes. The absence of analysis records does not show that analyses were not performed; it means that methods and results are not reported in the registry record.
Missing-data handling is also not reported. For the primary endpoint, the record does not state how many participants had measurements at both baseline and 4 weeks, whether measurements outside that interval were used, or how missing measurements were treated. General explanation: excluding participants without complete measurements can produce bias if missingness is related to health status or the outcome. Alternative methods rely on assumptions that should be described and assessed.
The record does not define analysis populations, such as whether all enrolled participants or only participants with usable follow-up measurements would be included in each outcome analysis. It also does not report a protocol-based analysis plan or explain whether any analyses were exploratory. As a result, the degree of prespecification, the handling of multiple outcomes and the possible effect of missing observations cannot be evaluated from 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 |
|---|---|---|---|
| Treatment (Cabozantinib-s-malate) | 4 | 20 | 20.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment (Cabozantinib-s-malate) | 18 of 20 |
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 |
|---|---|
| Treatment (Cabozantinib-s-malate) | 20 of 20 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment (Cabozantinib-s-malate) |
|---|---|---|
| hand foot syndrome | Musculoskeletal and connective tissue disorders | 1 of 20 |
| fatigue | General disorders | 1 of 20 |
| urinary infection | Renal and urinary disorders | 1 of 20 |
| elevated creatinine | Renal and urinary disorders | 1 of 20 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment (Cabozantinib-s-malate) |
|---|---|---|
| fatigue | General disorders | 17 of 20 |
| anorexia | Psychiatric disorders | 14 of 20 |
| hypertension | Vascular disorders | 12 of 20 |
| nausea | Gastrointestinal disorders | 10 of 20 |
| diarrhea | Gastrointestinal disorders | 9 of 20 |
| bone pain | Musculoskeletal and connective tissue disorders | 6 of 20 |
| dysgeusia | Gastrointestinal disorders | 6 of 20 |
| mucositis | Gastrointestinal disorders | 6 of 20 |
| rash | Skin and subcutaneous tissue disorders | 6 of 20 |
| dry mouth | General disorders | 5 of 20 |
Serious events with the highest arm-level rate: hand foot syndrome (5.0%), fatigue (5.0%), urinary infection (5.0%), elevated creatinine (5.0%).
The registry records serious adverse events affecting 4 participants, with 20 listed as at risk for serious adverse events. It also records other adverse events affecting 20 participants, with 20 listed as at risk for those events. The safety entry lists 18 deaths. These figures are registry counts, and the record does not report their timing or causes.
The listed serious-event terms are hand foot syndrome, fatigue, urinary infection and elevated creatinine. Each is recorded with a percentage of 5.0%. The registry does not provide enough detail to determine the severity, duration, recurrence or treatment attribution of each event from these entries alone. The percentages should therefore be read as recorded safety summaries, not as evidence that cabozantinib-s-malate caused the events.
General explanation: an adverse event is not necessarily caused by the treatment. Seriousness is a regulatory classification and is not synonymous with severity. Establishing a causal relationship requires clinical assessment and context, including when the event occurred, other possible causes, and how investigators classified it. That information is not reported in the registry record. The listed deaths likewise cannot be attributed to treatment based on the count alone.
12. What the Result Does, and Does Not, Mean
This registry record describes a pilot investigation of cabozantinib-s-malate in hormone-resistant metastatic prostate cancer. Its primary outcome was percentage change in PET SUV from baseline to 4 weeks, summarized by the median and full range. The record identifies the measurement and the interval but does not report the observed median or range. The amount and direction of the primary imaging change therefore cannot be determined from the registry record.
The study used a single-group design and did not include a comparator. Any observed before-and-after change in this design would describe the treated group; it would not establish the change that treatment caused. Without a comparison group, the record cannot distinguish a treatment-related effect from changes that could occur over time, measurement variability or other influences.
The registry lists secondary outcomes related to progression, toxicity and response, but does not report their numerical results or analyses. Safety entries include serious adverse events, other adverse events and deaths, but the registry does not report timing, causes or attribution sufficient to connect these events to treatment. These records should not be interpreted as demonstrating either benefit or harm caused by the intervention.
General explanation: a pilot study can help describe feasibility and generate questions for further research, but the value of such a study depends on the quality and completeness of its results and methods. The record does not report a statistical analysis plan, missing-data approach, analysis populations or uncertainty estimates for the primary outcome. Those omissions limit assessment of both the robustness and precision of any underlying findings.
The study’s stated imaging aim is distinct from demonstrating a clinical treatment effect. A change in an imaging measurement is not, by itself, evidence of improved symptoms, delayed progression or longer survival. The registry record does not establish that the primary imaging outcome predicts those outcomes. Accordingly, the record supports description of the study question and design, but not a conclusion about the treatment’s clinical effects.
13. Why This Trial Matters Statistically
This trial illustrates an important distinction between a measurement question and a treatment-comparison question. The registered endpoint asks how PET SUV changed within a treated group over a defined interval. That can be an informative descriptive question, particularly in a pilot focused on imaging pathways. It is not equivalent to estimating how outcomes differ between treatment strategies.
The choice of a median and full range also affects what can be learned from an outcome summary. The median describes the central observation, while the range shows the extremes. Neither alone communicates the precision of the estimate. An uncertainty interval and the underlying analysis details would help readers judge how stable the estimated change is, but those are not reported in the registry record.
The registry lists multiple outcome domains, including imaging, response, progression and safety. This breadth makes clear why prespecification and transparent reporting matter: readers need to know which outcome was primary, which analyses were planned, and how results across outcomes were interpreted. The record identifies a primary endpoint, but does not report its result or a multiplicity plan.
Finally, the safety entries demonstrate why event counts require context. Counts and percentages do not establish causation, and deaths cannot be interpreted without information about timing and cause. Clear reporting of attribution, analysis populations and missing measurements is essential to connect registry summaries to the questions researchers and clinicians ask. In this record, the design and intended endpoint are described, while key outcome and analysis details remain unreported.
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 interpretation is that the registry record does not report the observed primary PET SUV change, despite identifying the endpoint, its time frame and its summary statistics. No confidence interval or other uncertainty estimate is reported. The primary result’s direction, size and precision therefore cannot be assessed from this record.
The single-group design has no concurrent comparator, so it cannot estimate a treatment contrast or separate treatment-associated changes from other changes over time. The registry records no allocation and no masking. It does not provide detail on how imaging measurements were obtained or assessed, which limits evaluation of measurement consistency and possible observer effects.
The registry identifies enrollment of 20 but does not report the number included in the primary-endpoint analysis or the completeness of baseline and follow-up imaging. The missing-data approach and analysis populations are not reported. The registry also does not provide a detailed statistical analysis plan, sample-size justification, or multiplicity approach. These gaps limit assessment of prespecification, selection effects and statistical precision.
Safety entries lack information on event timing, causes and attribution to treatment. The record does not report enough context to interpret the listed deaths or adverse events as treatment-related. Results for the six listed outcome measures are also not reported in the analysis component. These limitations are specific to the information available in the registry record and do not establish what may have been reported elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Cabozantinib-S-Malate in Treating Patients With Hormone-Resistant Metastatic Prostate Cancer — NCT01812668.
- Registry record last updated 2021-08-05; status last verified 2021-08.
- Results first posted 2021-03-23.
- 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.
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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT01812668 is a completed, single-group pilot trial of oral cabozantinib-s-malate in hormone-resistant metastatic prostate cancer, sponsored by Barbara Ann Karmanos Cancer Institute. The registry lists enrollment of 20, no allocation, no masking and phase NA. The study started in 2013-03 and reached primary completion on 2019-01-18.
The primary outcome was percentage change in PET SUV from baseline to 4 weeks, summarized by the median and full range. Six outcome measures are listed. The registry record does not report the primary outcome estimate, an analysis plan, a missing-data method or analysis populations. Safety entries include serious adverse events affecting 4 participants, other adverse events affecting 20 participants, and 18 deaths; event timing, causes and treatment attribution are not reported.