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 Study of Xeloda (Capecitabine) in Women With HER2-Negative Metastatic Breast Cancer (NCT00121836), a non-randomized phase 4 study. The primary outcome is Overall Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00121836 |
| Phase | Phase 4 |
| Condition | Breast Cancer |
| Allocation | Non-Randomized |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 109 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Hoffmann-La Roche |
| Results posted | Yes |
2. Clinical Question
Population
Women with HER2-negative metastatic breast cancer. The study summary describes treatment-naïve patients receiving first-line treatment. The registry reports that 109 patients received study drug in the First Study Treatment Phase.
Intervention
Oral capecitabine, called Xeloda in the study title and summary, plus intravenous bevacizumab, called Avastin. The summary describes capecitabine 1000 mg/m² twice daily on Days 1-15 and bevacizumab 15 mg on Day 1 of each 3-week cycle.
Comparator
There was no randomized control group. The registry describes a non-randomized, single-group study, so the treatment combination is not compared with a concurrent like-for-like control arm in this record.
Primary question
The primary endpoint was overall survival: time from the first treatment dose to death, regardless of cause, across study phases. The record identifies a median and 95% confidence interval as the intended summary, but the median and interval are not reported in the registry record.
The clinical question is therefore descriptive: what overall-survival and safety information was recorded for patients receiving this treatment strategy? Because this was a single-group, open-label study, the posted information cannot by itself estimate how outcomes would have differed under another treatment. The record names capecitabine and bevacizumab as the drugs studied, but it does not provide a numerical overall-survival result or a randomized comparison. It reports a timeframe of approximately 505 days for the primary outcome, described as median time to death; that wording is a timeframe, not a reported median survival result.
3. Trial Design
This was a Phase 4, non-randomized, single-group, open-label study. The registry lists 109 enrolled participants and describes 109 patients as having received study drug in the First Study Treatment Phase. The study was completed. The recorded start is 2005-06 and primary completion is 2008-12.
The study summary describes first-line treatment with oral capecitabine plus intravenous bevacizumab in women with metastatic breast cancer. The regimen described was capecitabine 1000 mg/m² twice daily on Days 1-15 and bevacizumab 15 mg on Day 1 of each 3-week cycle. Anticipated time on study treatment was until disease progression or unacceptable toxicity. This describes the intended treatment approach; it does not establish how long each participant actually received treatment.
The registry reports that 54 patients withdrew prematurely during the First Study Treatment Phase and 54 proceeded to a Second Study Treatment Phase. It further states that all 54 who proceeded to that phase withdrew during it. The remaining population detail is truncated in the registry record, so it does not support a complete account of treatment disposition.
There was no masking and no randomized comparator. The adverse-event group title refers to capecitabine plus bevacizumab and paclitaxel or vinorelbine plus bevacizumab, but the record does not provide a randomized comparison between these regimens. A target sample size of <100 individuals is stated in the study summary; the registry lists 109 enrolled. The record does not report the sample-size justification or explain this difference. It also does not report a detailed statistical analysis plan.
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 | Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev |
|---|---|
| STARTED | 109 |
| COMPLETED | 54 |
| NOT COMPLETED | 55 |
Analysis population for the primary outcome, as defined in the registry: 109 patients (pts) received study drug in the First Study Treatment Phase. 54 pts withdrew prematurely, and 54 pts proceeded to the Second Study Treatment Phase. All 54 pts who proceeded to the Second Study Treatment Phase withdrew during that phase. 1 pt continued treatment in the First Study Treatment Phase and completed 3 years of follow-up.
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 | Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev |
|---|---|---|
| Participants analysed | 109 | |
| Age Continuous | Years | 56.7 (SD 12.03) |
| Sex: Female, Male: Female | Participants | 109 |
| Sex: Female, Male: Male | Participants | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Overall Survival, measured over approximately 505 days (Median Time to Death).
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | Days |
| Endpoint classification | Time-to-Event Analysis |
Overall survival was the primary endpoint. The registry defines it as the time from the date of the first treatment dose, Day 1, to the date of death, regardless of the cause of death, across study phases. It identifies the median as the summary measure and a 95% confidence interval as the measure of uncertainty. The stated timeframe is approximately 505 days, described as median time to death; this timeframe does not give the observed median value.
In general, overall survival is a time-to-event endpoint: the event is death, and the time origin and event definition determine what the measure represents. Using time to death can capture outcomes across the course of follow-up without restricting the endpoint to a particular cause of death. A median, when reported, marks the point at which the estimated survival experience reaches one half. A confidence interval describes uncertainty around an estimate; it is not a range containing a fixed proportion of individual patients’ survival times.
The registry record does not report the median overall-survival estimate or its 95% confidence interval. It also does not report the number of deaths, a survival curve, or a hazard ratio for this endpoint. The endpoint definition and timeframe therefore clarify what was intended to be measured, but they do not establish the numerical survival outcome.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies overall survival as the primary endpoint and specifies how it was defined, but it does not report the numerical median or its 95% confidence interval. Consequently, the posted registry information does not allow a reader to describe the observed median survival, quantify its precision, or assess the distribution of survival times. The approximately 505-day timeframe in the endpoint description is not a result estimate; it is presented as the timeframe for the measure.
The study design also determines what conclusions are supportable. It was open-label, non-randomized, and single-group, with no like-for-like concurrent control arm. Results from a single group can describe what was observed among the people treated, but they do not isolate the effect of treatment from other explanations for outcomes. Without a randomized comparison, differences between treatment groups cannot be estimated from this record.
The study summary describes a capecitabine-plus-bevacizumab regimen and planned treatment until disease progression or unacceptable toxicity. The registry also records movement from the First Study Treatment Phase to a Second Study Treatment Phase and withdrawals in both phases. These details matter when interpreting the population contributing to an endpoint defined across study phases. The record does not provide enough complete participant-flow information to reconstruct every person’s follow-up or endpoint status.
The safety record gives 109 at risk for serious and other adverse events, with figures of 39 and 103, respectively. It also lists serious-event terms with percentages. These figures describe the recorded safety information, but they do not provide event timing, duration, severity grading beyond the serious-event classification, or a comparison with an untreated or alternative-treatment group. The listed percentages should not be converted into counts without additional data.
The record lists four outcome measures and names adverse-event outcomes among its secondary outcomes. It reports zero analyses in the registry analysis listing. This means no analyses are listed in that part of the record; it does not establish that no analysis was performed. No multiplicity procedure, missing-data method, or detailed statistical analysis plan is reported. In particular, there is no basis in the registry record for describing adjustment choices, interim monitoring, or the handling of incomplete survival follow-up.
The posted information is therefore most useful as a description of study design, endpoint definition, participant disposition as far as recorded, and selected safety figures. It does not provide the primary numerical endpoint result needed to assess its estimate or precision. It also does not support causal claims about the regimen or comparison with another treatment.
9. Statistical Methods Explained
The registry describes a time-to-event primary endpoint and names the median and a 95% confidence interval as its intended summary. In general, time-to-event analysis uses both whether an event occurred and the time until it occurred. The event for this endpoint is death, measured from the first treatment dose. Participants who have not had the event by the end of observed follow-up can contribute information up to that point; this is commonly called censoring. The registry record does not report how censoring or incomplete follow-up was handled in the analysis.
What does a median survival estimate represent?
In general, the median survival time is the time by which the estimated probability of remaining alive reaches one half. It describes the middle of the estimated survival distribution, rather than the average survival time or the survival time of every participant. Its interpretation depends on the endpoint definition, follow-up, and analysis population. Although the record specifies a median summary, it does not report the median value. The approximately 505-day timeframe is not a substitute for that estimate.
How should the confidence interval be read?
In general, a confidence interval communicates uncertainty in an estimate under the assumptions of the statistical method used. A wider interval indicates less precision than a narrower interval, while the interval’s location indicates the values compatible with the estimate and method. It is not a range describing where most individual survival times fall. The record specifies a 95% confidence interval but does not report its endpoints, so its width and the precision of the survival estimate cannot be assessed.
What can a single-group design estimate?
A single-group study can describe outcomes observed among people who received the study regimen. It lacks a randomized concurrent group that would provide a direct treatment comparison. In general, random allocation helps make comparison groups similar in expectation with respect to measured and unmeasured characteristics. Without randomization and a suitable comparator, observed outcomes can reflect participant characteristics, disease course, subsequent care, or other factors as well as the treatment strategy. This is why a single-group result should not be interpreted as a causal estimate of treatment effect.
What do the safety counts and percentages convey?
Safety summaries commonly distinguish serious adverse events from other adverse events. The registry lists 109 at risk in each category, with 39 recorded in the serious-event affected figure and 103 in the other-event affected figure. It also lists percentages for selected serious-event terms. In general, a count or percentage is meaningful only with its definition, denominator, observation period, and event-collection rules. This record does not provide enough detail to determine all those features or to infer how many events occurred repeatedly in the same participant.
What does the sample-size illustration mean?
In general, a sample-size illustration describes the number of participants or events that a hypothetical future design might need under stated assumptions. The record’s description of the illustration specifies a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect expressed as a fraction of the observed effect. It distinguishes time-to-event illustrations, which use total events, from other illustrations, which use participants per arm. These are planning assumptions, not observed power and not evidence that the original study was designed or powered in that way. The registry does not report the trial’s own sample-size justification. No illustration values are available in the registry record for interpretation.
The registry analysis listing reports zero analyses. That listing does not supply an analysis method for the survival endpoint or establish that investigators performed no analysis. The record does not report a hazard ratio, adjustment method, model specification, interim analysis plan, or a method for handling missing outcome information. Any interpretation requiring those details would go beyond what the registry record states.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists four outcome measures and names secondary outcomes concerning adverse events, premature withdrawal due to adverse events, and marked laboratory abnormalities. It does not report a multiplicity strategy for evaluating several outcomes. In general, when multiple outcomes or statistical tests are considered, the chance of at least one apparently unusual result can depend on how many tests are conducted and how they are interpreted. Without a stated strategy, the record does not show whether or how that issue was addressed.
The registry analysis listing reports zero analyses. This indicates that no analyses are listed in that part of the record; it does not prove that no analyses were conducted. A detailed statistical analysis plan, including any planned interim analyses, is not reported in the registry record.
The record identifies 109 patients treated in the First Study Treatment Phase, 54 premature withdrawals in that phase, and 54 patients who proceeded to the Second Study Treatment Phase, all of whom withdrew during that phase. The remaining participant-flow text is incomplete. The registry does not explain how withdrawals, incomplete follow-up, or missing outcome information were handled in the overall-survival analysis. It also does not report the number of deaths or the analysis population used for the primary estimate.
These omissions limit assessment of whether the reported endpoint analysis, if conducted, included all treated patients and how uncertainty from incomplete follow-up was addressed. They do not establish that a particular method was or was not used; the relevant details are not reported 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 |
|---|---|---|---|
| Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev | 39 | 109 | 35.8% |
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 |
|---|---|
| Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev | 103 of 109 |
Most frequent serious adverse event terms
| Event term | Organ system | Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev |
|---|---|---|
| Pain | General disorders | 6 of 109 |
| Dehydration | Metabolism and nutrition disorders | 5 of 109 |
| Chest Pain | General disorders | 3 of 109 |
| Nausea | Gastrointestinal disorders | 3 of 109 |
| Vomiting | Gastrointestinal disorders | 3 of 109 |
| Pulmonary Embolism | Respiratory, thoracic and mediastinal disorders | 3 of 109 |
| Mucosal Inflammation | General disorders | 2 of 109 |
| Musculoskeletal Pain | Musculoskeletal and connective tissue disorders | 2 of 109 |
| Fatigue | General disorders | 1 of 109 |
| Influenza Like Illness | General disorders | 1 of 109 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Capecitabine+Bevacizumab (Bev); Paclitaxel or Vinorelbine +Bev |
|---|---|---|
| Palmar-Plantar Erythrodysaesthesia Syndrome | Skin and subcutaneous tissue disorders | 71 of 109 |
| Fatigue | General disorders | 68 of 109 |
| Diarrhoea | Gastrointestinal disorders | 66 of 109 |
| Nausea | Gastrointestinal disorders | 66 of 109 |
| Constipation | Gastrointestinal disorders | 41 of 109 |
| Vomiting | Gastrointestinal disorders | 36 of 109 |
| Anorexia | Metabolism and nutrition disorders | 35 of 109 |
| Alopecia | Skin and subcutaneous tissue disorders | 32 of 109 |
| Cough | Respiratory, thoracic and mediastinal disorders | 32 of 109 |
| Headache | Nervous system disorders | 32 of 109 |
Serious events with the highest arm-level rate: pain (5.5%), dehydration (4.6%), chest pain (2.8%), nausea (2.8%), vomiting (2.8%).
The registry lists 109 at risk for both serious and other adverse events. The serious-event figure is 39, and the other-event figure is 103. These are separate safety summaries; they should not be combined or treated as mutually exclusive categories. The registry also lists serious adverse-event terms with percentages: Pain, 5.5%; Dehydration, 4.6%; Chest Pain, 2.8%; Nausea, 2.8%; Vomiting, 2.8%; and Pulmonary Embolism, 2.8%.
These figures describe reported safety observations, not a comparison of risks between treatments. The study was single-group and non-randomized. The registry does not give event-level details, timing, duration, or the number of recurrent events for each term. It also does not explain in this record whether participants could contribute to multiple listed terms. The percentages should therefore be read as the registry’s reported figures, not as independently reconstructed counts or as evidence about differences from another treatment.
The adverse-event group title includes capecitabine plus bevacizumab and paclitaxel or vinorelbine plus bevacizumab. The record does not present these as randomized, like-for-like groups. Safety figures should not be attributed to a comparative treatment effect.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed, Phase 4, open-label, non-randomized, single-group study evaluated capecitabine plus bevacizumab in women with HER2-negative metastatic breast cancer. It gives the primary endpoint definition and reports selected participant-flow and safety information. These details help readers understand what was studied and how the endpoint was intended to be measured.
However, the record does not report the numerical median overall-survival result or its 95% confidence interval. It therefore does not show the estimated survival time or how precise that estimate was. The approximately 505-day timeframe is not the median result. Nor does the record report a hazard ratio or a randomized comparison that would quantify an outcome difference against another treatment.
In general, a result observed in a single group does not establish what would have happened to the same participants under a different treatment. The lack of randomization and a concurrent control means that outcomes cannot be attributed solely to the regimen based on this record. The safety figures are likewise descriptive; they do not show whether adverse-event risks were higher or lower than under another treatment.
The record also does not report a complete statistical analysis plan, missing-data procedures, or multiplicity handling. These gaps prevent assessment of several methodological choices that can affect interpretation. None of these absences establishes that an analysis or procedure was not performed; the details are simply not reported in the registry record.
Accordingly, the defensible interpretation is limited to the study’s stated design, treatment description, endpoint definition, and the safety and disposition figures that are recorded. The posted information does not establish a comparative treatment effect or provide the numerical primary endpoint result needed to judge its magnitude and precision.
13. Why This Trial Matters Statistically
This study illustrates why the design and reporting context matter as much as an endpoint label. Overall survival is a clearly defined time-to-event outcome, but the registry’s definition alone cannot tell readers what the observed result was. Without the median and confidence interval, neither the estimated survival time nor its precision can be evaluated from this record.
The single-group design is also central to interpretation. A treatment outcome observed without a randomized comparator is descriptive, not a direct estimate of how outcomes differ between treatment strategies. This distinction remains important even when a study has a named primary endpoint and a substantial enrolled population. The registry lists 109 enrolled and 109 patients receiving study drug in the First Study Treatment Phase, but those figures do not replace a control group or a reported endpoint estimate.
The record further shows how participant flow can complicate endpoint interpretation. It reports withdrawals in both study phases, while the remaining disposition detail is truncated. Since overall survival was defined across study phases, complete reporting of the population and follow-up would help readers understand who contributed information and how missing follow-up was addressed.
Finally, safety summaries need careful framing. The serious and other adverse-event figures and selected event percentages communicate recorded observations, but they do not establish comparative risk. Statistical interpretation depends on denominators, event definitions, follow-up, and the study design. The record’s missing analysis details and primary numerical result are therefore substantive limits on what can be concluded, not merely technical omissions.
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 important limitation for interpreting efficacy is that the registry record does not report the primary overall-survival median or its 95% confidence interval. It gives the endpoint definition and a timeframe of approximately 505 days, but that timeframe is not a numerical outcome estimate. The record also does not report deaths, a survival curve, or a hazard ratio.
The design was non-randomized, open-label, and single-group. There is no concurrent randomized comparator in the registry record, so outcomes cannot support a direct comparison of treatment strategies or isolate a treatment effect. The record does not report blinding or a comparative analysis capable of addressing this limitation.
Participant disposition is only partly described. The record reports withdrawals during the First Study Treatment Phase and withdrawals among patients who proceeded to the Second Study Treatment Phase, but its final population statement is truncated. It does not report how incomplete follow-up or missing survival information was handled, nor does it identify the analysis population for the primary endpoint.
The registry does not report the trial’s sample-size justification, a detailed statistical analysis plan, multiplicity handling, or interim analyses. Although a planning illustration is described, it is not the trial’s own design justification and its numerical values are not reported in the registry record. Safety information is also limited to summarized figures and selected serious-event terms; event timing, recurrence, and further detail are not reported. These gaps restrict evaluation of both the precision of outcomes and the methods used to analyze them.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: A Study of Xeloda (Capecitabine) in Women With HER2-Negative Metastatic Breast Cancer — NCT00121836.
- Registry record last updated 2011-04-27; status last verified 2011-04.
- Results first posted 2011-03-04.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
This completed Phase 4 study was non-randomized, open-label, and single-group. It evaluated capecitabine plus bevacizumab in women with HER2-negative metastatic breast cancer. The registry lists 109 enrolled and describes 109 patients receiving study drug in the First Study Treatment Phase.
Overall survival was the primary endpoint, defined from the first treatment dose to death regardless of cause, across study phases. A median and 95% confidence interval were specified, but the numerical result is not reported in the registry record. Selected safety figures and partial participant-flow information are recorded. No randomized comparator, detailed analysis plan, or missing-data method is reported.