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 Phase II Trial of Gemcitabine, Capecitabine, and Bevacizumab in Metastatic Renal Cell Carcinoma (NCT00523640), a non-randomized phase 2 study. The primary outcome is Objective Response Rate.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00523640 |
| Phase | Phase 2 |
| Condition | Carcinoma, Renal Cell |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of Chicago |
| Results posted | Yes |
2. Clinical Question
Population
People with metastatic renal cell carcinoma were the intended population. The registry record does not report further eligibility details or describe the characteristics of participants who entered the trial.
Intervention
The study examined a combination of gemcitabine, capecitabine, and bevacizumab. The record describes dosing on a 21 day cycle.
Comparator
There was no separate comparator group. The trial is recorded as single-group and non-randomized, so it does not provide a like-for-like control comparison.
Primary question
The primary endpoint was objective response rate at 12 weeks, defined using RECIST Criteria (V1.0). The registry record does not report the response count or response proportion.
The clinical question was whether this three-drug combination was associated with complete or partial tumor responses in people with metastatic renal cell carcinoma, and what effects, including adverse effects, were observed. The response definition relies on changes in target lesions measured by standard cross-sectional CT scanning. A complete response required disappearance of all target lesions; a partial response required a decrease of at least 30% in the sum of the longest diameters of target lesions. The endpoint combines these categories as response.
Because the trial had one treatment group and no randomized control arm, its primary question is descriptive rather than a direct comparison of treatment strategies. The record lists Overall Survival as a secondary outcome, but does not report an overall-survival result. It also does not report enough detail to determine how participants were selected, how response assessments were scheduled beyond the 12-week timeframe, or how assessors handled an assessment that could not be completed.
3. Trial Design
The registry record describes a Phase II, non-randomized, single-group trial with no masking. The listed enrollment is 30. The trial status is terminated; its recorded start is 2005-03 and its primary completion is 2011-04. These dates and status describe the registry record and do not, by themselves, explain why the trial ended or establish how many participants completed each assessment.
The intervention was gemcitabine, capecitabine, and bevacizumab. The arm description lists gemcitabine 1000 mg/m^2 on days 1 and 8, capecitabine 1000 mg (flat dose) by mouth twice daily on days 1-14, and bevacizumab 15 mg/kg on day 1, on a 21 day cycle. The record does not report treatment duration, dose-modification rules, or the reasons for any treatment discontinuations.
With one treatment group, there is no concurrent randomized control group against which to estimate a treatment contrast. Any response or safety description therefore concerns participants receiving the combination, not a difference between the combination and another regimen. Non-randomized treatment assignment also means the record cannot support a randomized comparison, even if other groups or historical results were available outside the registry record.
The primary outcome is Objective Response Rate, measured at 12 weeks. Overall Survival is listed as a secondary outcome. The registry record lists three outcome measures and one analysis, but does not report a detailed statistical analysis plan, define the analysis population, or state how missing assessments were treated. It also does not report the rationale for the enrollment target or whether interim analyses were planned.
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 | Combination of Gemcitabine, Capecitabine, and Bevacizumab |
|---|---|
| STARTED | 30 |
| COMPLETED | 29 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Combination of Gemcitabine, Capecitabine, and Bevacizumab |
|---|---|
| Death | 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 | Combination of Gemcitabine, Capecitabine, and Bevacizumab |
|---|---|---|
| Participants analysed | 29 | |
| Age, Continuous | years | 58 (36 to 82) |
| Sex: Female, Male: Female | Participants | 5 |
| Sex: Female, Male: Male | Participants | 24 |
| 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 | 1 |
| Race (NIH/OMB): White | Participants | 28 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 29 |
| Performance Status: 0 | participants | 5 |
| Performance Status: 1 | participants | 23 |
| Performance Status: 2 | participants | 1 |
| Number of metastatic disease sites: 1 | participants | 2 |
| Number of metastatic disease sites: 2 | participants | 6 |
| Number of metastatic disease sites: 3 or more | participants | 21 |
| Tumor histology: Clear cell | participant | 23 |
| Tumor histology: Poorly differentiated/unclassified | participant | 6 |
| Fuhrman grade: 1 | participants | 0 |
| Fuhrman grade: 2 | participants | 2 |
| Fuhrman grade: 3-4 | participants | 21 |
| Fuhrman grade: Unknown | participants | 6 |
| Prognostic risk group: Favorable | participants | 7 |
| Prognostic risk group: Intermediate | participants | 19 |
| Prognostic risk group: Poor | participants | 3 |
| Prior therapy-Nephrectomy: Yes | participants | 24 |
| Prior therapy-Nephrectomy: No | participants | 5 |
| Prior therapy-Radiotherapy: Yes | participants | 15 |
| Prior therapy-Radiotherapy: No | participants | 14 |
| Prior therapy-Cytokine therapy: Yes | participants | 8 |
| Prior therapy-Cytokine therapy: No | participants | 21 |
| Prior therapy-Oral Vascular Endothelial Growth Factor (VEGF) receptor kinase inhibitor: Yes | participants | 20 |
| Prior therapy-Oral Vascular Endothelial Growth Factor (VEGF) receptor kinase inhibitor: No | participants | 9 |
6. Primary Endpoint
The registry lists the primary outcome as Objective Response Rate, measured over 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | proportion |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint, Objective Response Rate, is a proportion: the share of participants classified as having either a complete response or a partial response by the stated assessment. The registry record sets the timeframe at 12 weeks and describes evaluation under RECIST Criteria (V1.0), using standard cross-sectional CT scanning.
Under the stated definition, complete response means disappearance of all target lesions. Partial response means a decrease of at least 30% in the sum of the longest diameters of target lesions. The endpoint counts either category as a response. It is intended to capture measurable tumor change over the specified assessment period, rather than an outcome such as survival or duration of response.
In general, a proportion is useful for describing how often a defined event occurs in a study group. Its interpretation depends on a clear event definition, a specified assessment time, and an identified population at risk of being assessed. A confidence interval, when reported, would communicate uncertainty around the estimated proportion; it would not remove limitations created by a single-group design or by missing assessments.
The registry record does not report the number of complete responses, partial responses, or participants included in the primary analysis. It therefore does not report the observed objective response rate or its precision. The endpoint definition alone describes what the trial intended to measure, not what the measurement found.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The central interpretive point is that the registry record identifies the trial's primary endpoint but does not report its primary outcome value. It states that objective response was assessed at 12 weeks under RECIST Criteria (V1.0), but no response count, proportion, confidence interval, or test result appears in the registry record recorded for this trial. The endpoint cannot be judged from its definition alone.
The design also constrains what a result could establish. This was a non-randomized, single-group Phase II trial with no masking and no concurrent comparator group. A response proportion from such a design would describe outcomes among participants assessed after receiving the combination. It would not, on its own, estimate how outcomes differ from those under another treatment or from what would have happened without the combination. Differences in patient characteristics, disease course, care, or assessment can affect comparisons with external experience.
The enrollment listed in the record is 30, while safety denominators are listed as 29. These are distinct record entries and should not be treated as interchangeable analysis populations. The primary endpoint population is not reported in the registry record, so it is not possible to establish from these registry entries whether all listed participants were eligible for response analysis, whether any lacked an assessment, or how such cases were handled.
For adverse events, the record lists 5 participants with serious adverse events and 20 with other adverse events, each among 29 at risk. These are counts recorded for the combination group. The record does not give event-level detail for all adverse events, exposure time, or a comparison group. The listed serious-event terms include pulmonary embolism/deep vein thrombosis, seizure, sepsis, and bowel perforation, with percentages as recorded. These figures should be read as safety descriptions, not as comparative estimates or evidence that the regimen caused each event.
Overall Survival is listed as a secondary outcome, but its result is not reported in the registry record. No conclusion about survival, comparative benefit, or the balance of benefits and harms can be drawn from the outcome details available. More generally, the registry entry does not report the detailed analysis methods, missing-data handling, or reasons for termination that would help contextualize any results.
9. Statistical Methods Explained
Statistical interpretation begins with the study design and the exact outcome definition. This trial is listed as single-group and non-randomized, with no masking. That structure can describe responses and adverse events within the treated group, but it does not create a randomized estimate of how outcomes differ between treatment options. The record lists one analysis, but does not report its methods in enough detail to identify the estimator, uncertainty calculation, or hypothesis test used.
What does a response proportion describe?
In general, a response proportion divides the number of participants meeting the response definition by the number included in the relevant analysis population. The numerator depends on the trial's response criteria; here, the registry definition combines complete and partial response. The denominator depends on the analysis rules, which are not reported in the registry record. Without the result and the denominator used for that result, the objective response rate cannot be reconstructed from the endpoint description.
In general, a confidence interval gives a range of values compatible with the data under a specified statistical method. Its width reflects statistical uncertainty as well as the amount and pattern of information available. A confidence interval does not account for every source of uncertainty: it cannot resolve bias from a non-randomized design, incomplete outcome assessment, or differences between this study group and another population. No confidence interval for the primary endpoint is reported in the registry record.
Why does the single-group design matter?
General: Randomization helps balance measured and unmeasured prognostic factors across treatment groups, on average. With no randomized comparator, an observed response proportion cannot separate the treatment's contribution from the natural course of disease, participant selection, other care, or assessment factors. This is why within-group response descriptions should not be presented as a controlled treatment effect. The registry record does not identify a control group or a planned external comparison.
General: Masking can reduce the influence of expectations on assessments or decisions. The record lists masking as none. It does not specify which study personnel or participants knew treatment details, nor does it describe independent review of imaging. Those assessment procedures are not reported in the registry record and should not be inferred from the endpoint definition.
How should safety counts be understood?
Safety counts are event summaries, and their interpretation depends on the definitions, follow-up period, and denominator. The record lists 29 at risk for serious and other adverse events; it reports 5 participants affected by serious adverse events and 20 affected by other adverse events. These participant counts are not the same as counts of individual event episodes. One participant may experience more than one event, and the record does not say whether event categories overlap. It also does not report exposure-adjusted rates or a comparator group.
General: Over-dispersion matters when variation in count outcomes exceeds what a simple count model assumes. In that setting, a model that allows for extra variation can yield more appropriate uncertainty than one that assumes the count variation is fully determined by its mean. The registry record describes the primary outcome as a proportion, not a count-rate model, and does not report a model for adverse-event counts. No conclusion about over-dispersion or model choice can be made for this trial from the information reported.
What can planning illustrations establish?
General: A sample-size calculation is a planning exercise based on assumptions about a target effect, variability, significance level, power, and design. It is not an observed result and should not be confused with the precision or strength of evidence actually achieved. The planning illustration associated with this record is described as based on the observed effect, with two-sided significance level 0.05, equal allocation between two arms, and a normal approximation; it is not the trial's own design. Since the trial itself is single-group, that illustration should not be read as a description of the enrolled design or as observed power. No planning sample-size values are reported in the registry record.
The registry record does not report the response result, an analysis population, confidence intervals, p-values, missing-data procedures, multiplicity procedures, or the statistical model used. The number of listed analyses does not substitute for those methods. Accordingly, the available details support explanation of the intended endpoint and design, but not a reconstruction of the trial's statistical analysis or a quantitative assessment of the primary result.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists Objective Response Rate as the primary outcome and Overall Survival as a secondary outcome. It also lists three outcome measures and one analysis. It does not report whether there were multiple timepoints, subgroup analyses, interim analyses, or multiple statistical tests, nor does it describe any adjustment for multiplicity. It is therefore not possible to determine from the record whether the analysis controlled the chance of false-positive findings across a set of comparisons.
Missing-data handling is also not reported in the registry record. For the 12-week response endpoint, the record does not state how participants without an assessable scan, who discontinued treatment, or whose status was otherwise unavailable were classified. It does not identify the analysis population or say whether participants were included according to enrollment, treatment received, or outcome availability. The listed enrollment of 30 and the safety risk count of 29 do not establish the denominator used for the primary endpoint.
General: Missing outcome data can affect an estimated proportion if the participants without assessments differ in response from those assessed. The direction and size of any such effect depend on why data are missing and on the analysis rules. Without the number and disposition of missing assessments or a stated method, that uncertainty cannot be quantified. The registry record also does not report whether sensitivity analyses were conducted.
Overall Survival is named as a secondary outcome, but the record does not report its result, time origin, censoring rules, or analysis method. No assumptions about those procedures should be made from the outcome name alone.
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 |
|---|---|---|---|
| Combination of Gemcitabine, Capecitabine, and Bevacizumab | 5 | 29 | 17.2% |
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 |
|---|---|
| Combination of Gemcitabine, Capecitabine, and Bevacizumab | 20 of 29 |
Most frequent serious adverse event terms
| Event term | Organ system | Combination of Gemcitabine, Capecitabine, and Bevacizumab |
|---|---|---|
| Pulmonary Embolism/Deep Vein Thrombosis | Blood and lymphatic system disorders | 3 of 29 |
| Seizure | Nervous system disorders | 1 of 29 |
| Sepsis | Infections and infestations | 1 of 29 |
| Bowel perforation | Gastrointestinal disorders | 1 of 29 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Combination of Gemcitabine, Capecitabine, and Bevacizumab |
|---|---|---|
| Neutropenia | Blood and lymphatic system disorders | 9 of 29 |
| Fatigue | General disorders | 6 of 29 |
| Leukopenia | Blood and lymphatic system disorders | 5 of 29 |
| Anemia | Blood and lymphatic system disorders | 4 of 29 |
| thrombocytopenia | Blood and lymphatic system disorders | 2 of 29 |
| Hand foot syndrome | Skin and subcutaneous tissue disorders | 2 of 29 |
| Dyspnea | Respiratory, thoracic and mediastinal disorders | 2 of 29 |
| Nausea | Gastrointestinal disorders | 2 of 29 |
| Emesis | Gastrointestinal disorders | 2 of 29 |
Serious events with the highest arm-level rate: pulmonary embolism/deep vein thrombosis (10.3%), seizure (3.4%), sepsis (3.4%), bowel perforation (3.4%).
The registry record lists 29 participants at risk for each of the adverse-event summaries. In the combination group, 5 participants are listed as affected by serious adverse events and 20 as affected by other adverse events. These are participant counts, not necessarily counts of distinct event types or total episodes.
The listed serious-event terms are pulmonary embolism/deep vein thrombosis at 10.3%, seizure at 3.4%, sepsis at 3.4%, and bowel perforation at 3.4%. These percentages are reproduced as recorded. The registry record does not give the event counts for each term, event timing, severity grades, or duration. It does not state whether a participant could appear under more than one term, so the percentages should not be added together.
General: Safety summaries depend on the observation period, how events were defined and collected, and the number of participants with available follow-up. A count of affected participants does not indicate how long each person was observed or whether an event occurred once or repeatedly. A single-group safety summary also cannot provide a comparative risk estimate against another treatment.
The record does not report a death count for this safety group. This should be read as a death figure not reported in the registry record, rather than as evidence that no deaths occurred. The listed events describe reported safety findings; they do not establish that the combination caused them.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a Phase II trial evaluated gemcitabine, capecitabine, and bevacizumab in a single, non-randomized group for metastatic renal cell carcinoma. It defines objective response at 12 weeks using RECIST Criteria (V1.0), and provides selected safety counts and serious-event terms. These are useful details about the design and the outcomes the record captures.
However, the registry record does not report the primary response count or proportion. Without that result, the central efficacy outcome cannot be described quantitatively. The record also does not report a result for the listed secondary outcome, Overall Survival. Consequently, these registry entries do not establish whether participants experienced responses or how long they survived.
Even if a response proportion were available, the single-group, non-randomized design would limit its interpretation. A proportion would describe the observed response frequency in the analyzed group, not a randomized difference from another treatment. No causal conclusion or comparative treatment claim follows from the design alone. The record's lack of a reported comparator is especially important when interpreting any within-group outcome.
The adverse-event entries indicate that serious and other events were recorded among participants at risk, with selected serious-event terms and percentages. They do not establish comparative safety, the likelihood of an event under another regimen, or whether the treatment caused a specific event. The death count is not reported in the registry record.
In general, statistical precision is conveyed by uncertainty measures such as confidence intervals, while design quality and outcome completeness affect the credibility of the estimate itself. The registry record does not report a primary-result estimate or its precision, nor does it state how missing outcome data were handled. The trial therefore supports a description of its stated aims, design, endpoint definition, and recorded safety summaries, but the available result information is insufficient to quantify the primary outcome or draw a comparative conclusion.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how an endpoint and a study design must be read together. Objective response rate has a clear stated definition: complete and partial responses under RECIST Criteria (V1.0), assessed at 12 weeks. But a defined endpoint is not itself a result. The registry record does not report the observed response proportion, making the distinction between planned measurement and reported finding especially important.
The single-group, non-randomized design also illustrates the difference between describing outcomes and estimating a comparative treatment effect. A one-group study can document what was observed among participants receiving a regimen, but it cannot provide a randomized contrast against a concurrent control. This limits interpretation even when an outcome estimate is available.
The safety entries provide another useful statistical distinction: participants affected are not the same as total event episodes, and percentages for individual terms should not be combined without knowing whether categories overlap. The record lists 29 at risk for safety summaries and reports serious and other event counts, but it does not give exposure time or a comparison group.
Finally, the registry record demonstrates why analysis populations, missing-data handling, uncertainty estimates, and multiplicity procedures matter. Those details influence how a result should be read, yet they are not reported in the information available for this trial. Sample-size planning illustrations, when distinct from the actual design, are not observed power or evidence that a study detected an effect. Clear separation of design details, endpoint definitions, safety summaries, and unreported outcomes helps prevent stronger claims than the record supports.
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.
Several trial-specific limitations affect interpretation. The design is recorded as non-randomized and single-group, with no masking. There is no concurrent control group for a like-for-like comparison, so the registry record cannot support a randomized estimate of the combination's effect relative to another strategy.
The primary endpoint result is not reported in the registry record. Although objective response rate and its 12-week RECIST definition are given, the record does not provide the response count, proportion, or uncertainty estimate. Overall Survival is listed as a secondary outcome, but its result is also not reported. These omissions prevent quantitative interpretation of the principal efficacy outcome and the listed survival outcome.
The record lists enrollment of 30, but does not report the primary analysis population or how many participants had an evaluable 12-week assessment. The safety summaries use 29 at risk; that number does not establish the primary endpoint denominator. Missing-data methods, assessment disposition, and sensitivity analyses are not reported.
Additional trial details that could shape interpretation are not reported in the registry record, including eligibility criteria, participant characteristics, treatment duration, dose modifications, imaging review procedures, and reasons for termination. The record also does not describe a statistical analysis plan, interim analyses, multiplicity handling, or the rationale for the enrollment target. For safety, event-level counts for the listed terms, exposure time, and a death count are not reported. These gaps limit assessment of precision, completeness, and generalizability.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Phase II Trial of Gemcitabine, Capecitabine, and Bevacizumab in Metastatic Renal Cell Carcinoma — NCT00523640.
- Registry record last updated 2014-02-11; status last verified 2014-01.
- Results first posted 2011-12-22.
- 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
The registry record describes a Phase II, non-randomized, unmasked, single-group trial of gemcitabine, capecitabine, and bevacizumab for metastatic renal cell carcinoma. Listed enrollment is 30; status is terminated. The recorded start is 2005-03 and primary completion is 2011-04.
The primary endpoint was Objective Response Rate at 12 weeks, defined using RECIST Criteria (V1.0). Overall Survival is listed as a secondary outcome. The primary response result and the survival result are not reported in the registry record.
For safety, 29 participants are listed at risk, with 5 affected by serious adverse events and 20 affected by other adverse events. Selected serious-event terms and percentages are recorded, while the death count is not reported. The record does not report the primary analysis population, missing-data procedures, detailed statistical methods, or a comparator group.