Study Of Sunitinib With Capecitabine In Breast Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study Of Sunitinib With Capecitabine In Breast Cancer (NCT00662025), a non-randomized phase 2 study. The primary outcome is Number of Participants With Objective Response Based on Data Review Committee's Assessment.

2. Clinical Question

In statistical terms, the central question is descriptive: among the defined analysis population receiving the combination, how many met the registry’s confirmation-based response criteria during the specified assessment schedule? The endpoint is not a direct estimate of the difference between two treatment groups, because the study is single-group. Without a reported numerical primary result, the frequency of response, its precision, and any uncertainty interval cannot be characterized from the registry record.

3. Trial Design

This was a Phase II, non-randomized, single-group study with no masking. The registry lists 63 participants enrolled and identifies advanced or metastatic breast cancer as the condition. Its stated objective was to evaluate efficacy, safety, and pharmacokinetics of sunitinib plus capecitabine in Japanese patients with advanced or metastatic breast cancer. The study is recorded as completed. Its start is listed as 2008-04, and its primary completion as 2009-12.

Because there was only one group, the design can describe outcomes observed among participants receiving the combination, but it does not create a randomized comparison with a control group. Non-randomized allocation also means there is no basis in this design for treating any external or historical group as an equivalent counterfactual. The registry record does not report a control arm, the details of treatment administration, or an arm description beyond the single-group structure.

The primary endpoint was the number of participants with objective response based on the Data Review Committee’s assessment. It was assessed from Day 1 of Cycle 2, every 6 weeks after Cycle 2, and at the end of Cycle 8. Response meant confirmed complete response or confirmed partial response under RECIST version 1.0. The endpoint description requires a repeat evaluation at least 4 weeks after the initial documentation for a response to be considered confirmed.

The registry also lists secondary outcomes covering investigator-assessed objective response, clinical benefit response assessed by a Data Review Committee and by investigators, progression-free survival, time to tumor progression, duration of objective tumor response, time to objective tumor response, and overall survival. The presence of these outcome names does not establish that each result is available or interpretable. Their numerical results and detailed analysis methods are not reported in the registry record.

Enrollment is not interchangeable with the primary endpoint analysis population. The Full Analysis Set is defined as diagnosed participants who received at least one dose of study medication, while the registry’s enrollment figure is 63. The number meeting the Full Analysis Set definition is not reported in the registry record. Nor are exclusions, withdrawals, or endpoint-specific denominators reported.

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.

Before assignment: The study consisted of 2 cohorts. Cohort 1 enrolled 6 participants. All adverse events in Cohort 1 were evaluated at the end of Cycle 2, and study continuation to Cohort 2 was determined based on the recommendation from the Independent Safety Monitoring Committee. Cohort 2 consisted of 63 participants, including the 6 participants in Cohort 1.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Full Analysis Set (FAS) is defined as the population of all participants who are diagnosed as having advanced/metastatic breast cancer and received at least one dose of study medication.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants With Objective Response Based on Data Review Committee's Assessment, measured over Day 1 of Cycle 2, every 6 weeks after Cycle 2, and at the end of Cycle 8..

The primary endpoint counts participants who achieved an objective response according to the Data Review Committee’s assessment. Under RECIST version 1.0, complete response means disappearance of all target and non-target lesions. Partial response means at least a 30% decrease in the sum of the longest dimensions of target lesions, using the baseline sum as reference. The registry requires the response to persist on repeat evaluation at least 4 weeks after it was first documented.

Counting participants with a confirmed response gives a clinically interpretable summary of tumor response in the study population. Requiring confirmation can reduce the chance that a transient or uncertain assessment is counted as a response. The scheduled assessments began on Day 1 of Cycle 2, continued every 6 weeks after Cycle 2, and included assessment at the end of Cycle 8.

As a count endpoint, the measure records whether each participant met the response definition, rather than the size of an individual participant’s tumor change. A response count alone does not describe response duration, time to response, progression-free survival, or overall survival; those are separately named outcomes in the registry. The primary count, its denominator, and an uncertainty interval are not reported in the registry record, so the observed response frequency and its precision cannot be stated.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine how observations are converted into estimates and how uncertainty around those estimates is described. For this study, the primary outcome is a count of participants meeting a binary response definition: each participant either met the confirmed objective-response criteria or did not. The registry describes the definition and assessment timing, but the numerical response result and the analysis method used for that result are not reported in the registry record.

What does a binary endpoint represent?

As a general statistical concept, a binary endpoint reduces each participant’s outcome to one of two categories. A count of responders is straightforward to interpret, but its meaning depends on the denominator: a count without the number analyzed cannot establish the response proportion. An interval estimate can express the uncertainty associated with an estimated proportion. Such an interval reflects sampling uncertainty under its method and assumptions; it does not correct for design limitations such as the lack of a comparison group. The registry record does not report the primary count, analysis denominator, response proportion, or interval estimate.

Why does confirmation matter?

The endpoint requires complete or partial response to be confirmed on repeat evaluation at least 4 weeks after initial documentation. In general, confirmation rules aim to distinguish sustained findings from observations that may not persist on reassessment. Confirmation can also affect which participants qualify as responders if an assessment is absent or does not meet the criteria at follow-up. The registry record does not report how incomplete or unevaluable confirmation assessments were handled.

What does the assessment schedule contribute?

The stated assessment schedule begins on Day 1 of Cycle 2, continues every 6 weeks after Cycle 2, and includes the end of Cycle 8. In general, outcome ascertainment depends on when and how measurements are made. Assessment timing can affect whether a response is detected and whether there is an opportunity to confirm it. The registry record does not report deviations from the schedule, the number of assessments completed, or how differences in follow-up were incorporated into analysis.

How should a single-group result be understood?

In a single-group study, a response count describes outcomes within the treated group. General statistical reasoning distinguishes that descriptive estimate from a treatment contrast, which requires outcomes under a comparator and a method for comparing groups. Random allocation is one approach to making groups comparable on average; this study is recorded as non-randomized and single-group. Therefore, even if a response frequency were available, it would not by itself estimate a difference attributable to treatment. A benchmark or external comparison is not reported in the registry record.

What do uncertainty intervals and significance tests add?

As a general concept, a confidence interval communicates the range of values reasonably compatible with an estimate under the statistical model and sampling assumptions. A significance test evaluates compatibility with a specified null hypothesis under its assumptions. Neither measure resolves bias from a missing comparator, unrepresentative participation, incomplete follow-up, or outcome-assessment differences. The registry record does not report a confidence interval, a primary-endpoint significance test, a null hypothesis, or an associated p-value.

What is over-dispersion, and does it apply?

As a general statistical concept, over-dispersion occurs when observed variability exceeds what a chosen model expects. It can make standard errors too small if a model assumes less variability than is present. For participant-level binary outcomes, the chosen model and its assumptions determine how uncertainty is estimated; over-dispersion is more directly a concern in some count-model settings. The primary endpoint is described as a participant count, but the analysis model and any assessment of over-dispersion are not reported in the registry record. There is therefore no basis to claim that over-dispersion was assessed or adjusted for.

How do the planning illustrations differ from trial results?

General sample-size calculations ask how many observations might be required to detect a specified effect under explicit assumptions. The planning illustration associated with the posted material is based on an observed effect, uses a two-sided significance level of 0.05, assumes equal allocation between two arms, and uses a normal approximation. Its effect to detect is a stated fraction of the observed effect. These are planning assumptions, not a description of the actual single-group design. The calculation is not observed power and does not establish the likelihood that the completed study detected an effect. The registry record does not report the trial’s original sample-size justification, target effect, or design calculation.

For time-to-event planning, a general method may express the requirement in terms of total events rather than participants, because information depends on the number of observed events. The planning notes identify this distinction for time-to-event outcomes. The trial’s actual event counts and time-to-event analysis methods are not reported in the registry record. No planning output should be read as a result for progression-free survival, time to tumor progression, or overall survival.

Finally, statistical analysis depends on defining the analysis population and handling incomplete observations consistently. The registry defines the Full Analysis Set as diagnosed participants who received at least one dose of study medication. It does not report the actual size of that set, exclusions from it, or endpoint-specific missing-data procedures. Those omissions limit independent assessment of the analysis even apart from the absence of the numerical primary result.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint and multiple secondary outcomes. In general, assessing several outcomes can increase the chance that at least one result appears unusual by chance if each is tested without accounting for the number of tests. A prespecified hierarchy, adjustment procedure, or clear distinction between confirmatory and exploratory analyses can help readers understand how multiple findings should be interpreted. The multiplicity strategy, any hierarchy among outcomes, and any adjustment for multiple testing are not reported in the registry record.

Missing outcome data can also affect interpretation. For the primary response measure, incomplete assessments or missing confirmation could influence who qualifies as a responder and the denominator used. General methods may use explicit rules for unevaluable participants, sensitivity analyses, or assumptions about missing outcomes. The registry record does not report how missing assessments, withdrawals, or unconfirmed responses were handled, nor does it report sensitivity analyses.

The registry defines the Full Analysis Set as participants diagnosed with advanced or metastatic breast cancer who received at least one dose of study medication. It reports enrollment of 63, but the number included in the Full Analysis Set and any exclusions are not reported in the registry record. The denominator used for the primary endpoint is likewise not reported in the registry record. This prevents checking whether the endpoint count and analysis population align with the stated definition.

The registry names both committee-assessed and investigator-assessed outcomes, but the relationship between those assessments and any planned analysis hierarchy is not reported in the registry record. Different assessors can produce different classifications; general statistical interpretation therefore benefits from clear information about assessment procedures and how disagreements or missing reviews are resolved. Those details are not reported. No assumptions about the handling of multiplicity or missing data should be inferred from the outcome list alone.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: thrombocytopenia (4.8%), decreased appetite (4.8%), fatigue (3.2%), malaise (3.2%), pyrexia (3.2%).

The registry’s safety summary lists 63 participants at risk for serious adverse events and 17 affected. It also lists thrombocytopenia and decreased appetite at 4.8% each, and fatigue, malaise, pyrexia, and hepatic function abnormal at 3.2% each among the top serious terms. These are descriptive entries for the sunitinib-plus-capecitabine group; they are not comparisons against another treatment group.

For the other adverse-event category, the registry lists 63 participants at risk and 63 affected. The category’s detailed definition and event-level breakdown are not reported in the registry record. A count of affected participants is distinct from a count of events, since one participant may experience more than one event. The registry information does not establish how many events occurred or their duration.

Percentages describe the registry’s reported values, but the denominator and calculation details for each listed term are not reported in the registry record. The serious-event summary should not be interpreted as a complete account of severity, timing, relatedness, or clinical course. Deaths are not reported in the registry record; that absence should not be interpreted as evidence that no deaths occurred.

12. What the Result Does, and Does Not, Mean

The registry record establishes that a Phase II study evaluated sunitinib plus capecitabine in Japanese patients with advanced or metastatic breast cancer. It identifies the primary endpoint as a confirmed objective-response count assessed by a Data Review Committee under RECIST version 1.0. It also reports a non-randomized, single-group design and enrollment of 63 participants. These features describe the question and structure of the study, not the numerical answer to its primary question.

The primary response count and the analysis results are not reported in the registry record. As a result, the observed response frequency and its precision cannot be characterized from this information. The endpoint definition does not substitute for the result: knowing what counted as a response is different from knowing how many participants met that definition.

Even with a reported response count, a single-group study would provide a within-group description rather than a randomized treatment contrast. It could not establish from its design alone what would have happened to comparable participants under another treatment. Non-randomized, single-group observations also cannot by themselves separate the contribution of the regimen from other explanations for observed outcomes. No claim of comparative benefit follows from the design information alone.

The safety summary records 17 participants affected among 63 at risk for serious adverse events, and lists several serious-event terms with their reported percentages. These figures describe the registry entries, not relative safety against a control group. They do not give a complete account of event severity, timing, or relatedness. The registry does not report deaths; this should not be taken to mean that none occurred.

The secondary outcome names indicate that the study tracked other efficacy measures, including time-to-event and response-duration outcomes. Their results are not reported in the registry record. Planning illustrations, where presented, are hypothetical calculations under stated assumptions and are not observed outcomes or observed power. Overall, the information supports a careful account of design, definitions, and reported safety counts, while leaving the primary efficacy estimate and comparative interpretation unresolved.

13. Why This Trial Matters Statistically

This study is statistically informative as an example of why an endpoint definition, a design description, and a numerical result must be considered together. The registry clearly defines objective response using confirmed RECIST version 1.0 criteria, identifies the assessment schedule, and specifies a Data Review Committee assessment. Those details make the intended outcome more interpretable than an endpoint label alone. However, the primary response count and analysis result are not reported in the registry record, so the central estimate and its uncertainty cannot be evaluated.

The non-randomized, single-group structure is also important. A response count in one group may describe observed outcomes, but it is not a treatment contrast. The design therefore illustrates the distinction between estimating an outcome within a cohort and estimating a comparative effect. This distinction remains important regardless of how precisely a within-group count might be measured.

The registry lists multiple secondary endpoints and both committee and investigator assessments. This highlights general statistical questions about outcome selection, assessment consistency, multiplicity, and missing data. The registry record does not report the procedures used to address those questions. Readers should distinguish outcomes that are merely listed from outcomes with reported analyses and interpretable estimates.

The safety entries likewise show why counts, denominators, event definitions, and comparator information matter. The serious adverse-event summary includes 17 affected participants among 63 at risk, but a single-group figure cannot establish comparative risk. A reported count also does not, by itself, describe event severity, timing, or the number of events per participant.

Finally, planning calculations are not substitutes for results or for the original design rationale. Their assumptions can illustrate how sample size depends on a target effect and statistical choices, but they do not reveal the trial’s original justification, which is not reported in the registry record. The trial’s statistical significance lies in these interpretive distinctions: a well-defined endpoint is valuable, but sound conclusions also require reported estimates, uncertainty, analysis populations, and a design suited to the comparison being claimed.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The main trial-specific limitation for interpretation is the absence of the primary endpoint result from the registry record. Although the endpoint is defined in detail, the response count, denominator, response proportion, and uncertainty estimate are not reported. The efficacy result therefore cannot be quantified from the registry information.

The study is recorded as non-randomized and single-group, with no masking. No control group is reported. Consequently, the design does not support a randomized, like-for-like comparison, and an observed outcome in the study group would not alone identify a comparative treatment effect. The registry does not report an external benchmark or a method for making such a comparison.

The registry identifies enrollment of 63 and defines the Full Analysis Set, but does not report the number analyzed in that population or the endpoint-specific denominator. Exclusions, withdrawals, completion of scheduled response assessments, and handling of missing or unconfirmed assessments are not reported in the registry record. These details are necessary for judging how the endpoint count relates to the enrolled population.

Although several secondary outcomes are named, their numerical results and analysis methods are not reported in the registry record. The multiplicity strategy, prespecified hierarchy, and any sensitivity analyses are also not reported. The same is true for the original sample-size rationale, interim analyses, and detailed statistical plan.

For safety, the registry provides summary counts and selected serious-event terms but not detailed event-level information, definitions for the other adverse-event category, or a complete account of timing, severity, and relatedness. Deaths are not reported in the registry record. These limitations restrict interpretation of both benefit-related outcomes and safety information without implying that unreported events or analyses did not occur.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study Of Sunitinib With Capecitabine In Breast Cancer — NCT00662025.
• Registry record last updated 2013-05-27; status last verified 2013-05.
• Results first posted 2010-10-13.
• 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.

18. Record Summary

The registry record describes a completed Phase II, non-randomized, single-group study of sunitinib plus capecitabine in Japanese patients with advanced or metastatic breast cancer. Enrollment was 63. The primary endpoint was the number of participants with confirmed objective response based on a Data Review Committee assessment under RECIST version 1.0. The Full Analysis Set was defined as diagnosed participants who received at least one dose of study medication.

The primary endpoint’s numerical result, analysis denominator, and precision estimate are not reported in the registry record. The registry lists secondary response, clinical benefit, progression, response-duration, and survival outcomes, but their numerical results are not reported in the information. The safety summary lists 17 participants affected among 63 at risk for serious adverse events, with selected event terms and percentages. The design provides no randomized comparator, and the statistical plan, missing-data procedures, and multiplicity approach are not reported in the registry record.