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 Capecitabine (Xeloda) and Lapatinib (Tykerb) as First-line Therapy in HER2/Neu-positive Breast Cancer (NCT00496366), a na phase 2 study. The primary outcome is Determine the Response Rate (as Determined by RECIST Criteria) of Capecitabine and Lapatinib as First-line Therapy in Patients With Advanced or Metastatic Breast Cancer That Overexpress HER2..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00496366 |
| Phase | Phase 2 |
| Condition | Breast Cancer, Metastatic Breast Cancer, Advanced Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 11 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Rutgers, The State University of New Jersey |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned patients with advanced or metastatic breast cancer that overexpresses HER2/Neu. The registry describes the intended population as receiving first-line therapy. It lists breast cancer, metastatic breast cancer, advanced breast cancer, and HER2/Neu-positive breast cancer among the conditions. The enrollment recorded is 11. The registry does not report a more detailed description of the patients included in the outcome analysis, and it says the study ended early with insufficient data to assess the primary outcome.
Intervention
The listed regimen combined capecitabine, also known as Xeloda, with lapatinib, also known as Tykerb. The arm description schedules capecitabine for Days 1–14 followed by a week without capecitabine, and lapatinib continuously for Days 1–21. These schedules describe the planned treatment pattern; the registry does not report how many patients completed treatment or their adherence.
Comparator
The study has a single-group model and lists one treatment arm: capecitabine plus lapatinib. Although the brief summary describes an interest in comparing the combination with capecitabine alone, the registry record does not list a capecitabine-only control group. There is therefore no within-trial, like-for-like treatment comparison in the posted design.
Primary question
The primary question was the response rate, assessed using RECIST criteria, for the combination as first-line therapy in advanced or metastatic HER2/Neu-overexpressing breast cancer. The stated timeframe was 2 years. The registry says the trial was terminated early and that insufficient data were collected to assess this outcome. As a result, the record does not establish a response-rate estimate or a comparison with capecitabine alone.
3. Trial Design
The registry identifies this as a phase II study of capecitabine plus lapatinib in advanced or metastatic HER2/Neu-overexpressing breast cancer. It records a single-group model, allocation as not applicable, and no masking. The only listed arm received the combination; no control arm is described. The registry's brief summary discusses comparing capecitabine with the combination, but the structured design does not include a capecitabine-only group. The record therefore supports a description of the combination arm, not a randomized or concurrent comparison between treatments.
The recorded enrollment is 11. The study status is terminated. The start date is 2007-07-23, and the primary completion date is 2009-12-31. These record dates do not explain when or why the trial stopped. The registry states that the study was terminated early and that insufficient data were collected to assess the primary outcome. The reason for termination, recruitment history, and any operational details about stopping are not reported in the registry record.
The combination schedule specifies capecitabine on Days 1–14, then a week without capecitabine, and continuous daily lapatinib on Days 1–21. The registry record does not describe dose levels, dose modifications, treatment duration beyond this schedule, adherence, or subsequent treatment. It also does not report randomization procedures, an allocation sequence, or blinding beyond recording no masking. The rationale for the sample size and the planned statistical analysis are not reported in the registry record.
The registry lists secondary aims related to clinical benefit, time to disease progression, and overall outcome, but the listed text is incomplete. It records two outcome measures and no analyses. Thus, the design information sets out the intended clinical questions, while the outcome record is too incomplete to support efficacy conclusions.
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 (Xeloda) + Lapatinib (Tykerb) |
|---|---|
| STARTED | 11 |
| COMPLETED | 10 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Capecitabine (Xeloda) + Lapatinib (Tykerb) |
|---|---|
| Death | 1 |
Analysis population for the primary outcome, as defined in the registry: Study to was terminated early and insufficient data was collected to assess this outcome measure.
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 (Xeloda) + Lapatinib (Tykerb) |
|---|---|---|
| Participants analysed | 11 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 6 |
| Age, Categorical: >=65 years | Participants | 5 |
| Age, Continuous | years | 60.7 (39 to 78) |
| Sex: Female, Male: Female | Participants | 11 |
| Sex: Female, Male: Male | Participants | 0 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 9 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 1 |
| 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 | 9 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Determine the Response Rate (as Determined by RECIST Criteria) of Capecitabine and Lapatinib as First-line Therapy in Patients With Advanced or Metastatic Breast Cancer That Overexpress HER2., measured over 2 years.
| Element | Registry entry |
|---|---|
| Result type | N/A |
| Measure of spread | not applicable |
| Unit | not stated |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is the response rate according to RECIST criteria, with a stated timeframe of 2 years. In general, response criteria provide standardized rules for classifying changes in tumor burden using clinical assessment, helping make response outcomes more consistent across patients and studies. A response rate is intended to describe the proportion of an analyzed group meeting the specified response definition. This is a general explanation of the endpoint concept; the registry does not provide the response classifications or the analysis denominator for this study.
Response rate is used in clinical research because it focuses on tumor change during treatment and can provide an interpretable measure of antitumor activity. It is not, by itself, a complete account of how long a response lasts, how long disease control persists, or how patients fare overall. The registry also lists secondary aims involving clinical benefit and time to disease progression, but it does not provide results for those aims in the record.
For this trial, the key limitation is explicit: early termination left insufficient data to assess the primary response-rate outcome. No response count, response-rate estimate, uncertainty interval, or test result is reported in the registry record. The endpoint's intended definition and timeframe can therefore be described, but its value cannot be estimated from the posted outcome information.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The primary result is not an observed estimate of treatment response. The registry states that the study was terminated early and that insufficient data were collected to assess the response-rate endpoint. No response count or response rate is reported. It is therefore not possible to judge the size or precision of a response estimate from this record, or to determine whether the endpoint was met.
The treatment question also cannot be answered as a comparative question from the posted design. Although the brief summary describes comparing capecitabine with capecitabine plus lapatinib, the structured record lists a single group receiving the combination and no capecitabine-only group. Without a concurrent comparator, the study cannot estimate a between-group treatment effect. Outcomes in a single treated group would not, by themselves, separate treatment effects from the course of disease, patient selection, or other influences.
The enrollment recorded is 11, but enrollment alone does not show how many patients contributed evaluable primary-outcome data. The registry does not give the analysis population, the number assessed at the stated endpoint, reasons for missing assessments, or handling of missing data. It would be inappropriate to assume that everyone recorded as enrolled contributed to the response analysis.
The registry records safety information for the combination arm: 3 of 11 at risk had a serious adverse event, 11 of 11 at risk had other adverse events, and deaths were recorded as 1. The listed serious adverse-event terms include diarrhea (18.2%), sepsis (9.1%), death (9.1%), and vomiting (9.1%). These entries describe reported safety observations in this small, single-group record; they do not establish comparative safety. The record does not provide enough context to determine event timing, duration, causal attribution, or the method used to collect events.
Overall, the posted results chiefly establish that a phase II combination study was conducted and terminated early, with insufficient primary-outcome data. The record does not provide an efficacy estimate or a controlled comparison. This is a limitation of what the registry reports, not evidence that the combination did or did not produce a particular response.
9. Statistical Methods Explained
The statistical information must be interpreted in light of the single-group design and the absence of a primary-outcome result. The registry lists no analyses. It does not report an analysis plan, a response count, an estimated response rate, a confidence interval, or a p-value. Consequently, there is no posted efficacy calculation to interpret. The methods below explain the relevant statistical concepts in general and distinguish them from analyses documented for this trial.
What would a response-rate estimate represent?
In general, a response-rate estimate describes the observed fraction of an analyzed group that meets a prespecified response definition. Its interpretation depends on how response is defined, who is included in the analysis, when assessments occur, and how unevaluable patients are handled. Those details matter because different analysis populations or missing-data rules can change the estimate. For this study, RECIST is named as the response criterion and 2 years is the stated timeframe, but the registry does not report the response classifications, evaluable population, or missing-data rules. No estimate can therefore be reconstructed from the posted record.
Why does uncertainty matter?
In general, a confidence interval describes the range of values reasonably compatible with the observed data under the statistical method used. It communicates precision as well as the estimate itself: a less precise estimate leaves more uncertainty about the underlying response rate. A confidence interval cannot be interpreted without knowing the analysis population and method, and it cannot be calculated from an outcome count that is not reported. No confidence interval for the primary endpoint appears in the registry record.
A p-value, in general, measures how surprising data would be under a specified null hypothesis and assumptions. It does not measure the probability that a treatment works, nor does it describe clinical importance. For a single-group response endpoint, a hypothesis test would require a specified reference value or other comparison framework. The registry does not report such a plan or a p-value. The planning significance level described for hypothetical sample-size illustrations is not a trial result or a p-value.
What can a single-group design estimate?
In general, a single-group study can describe outcomes observed among participants who receive the study regimen. It cannot, on its own, provide a randomized estimate of how those outcomes differ from what would have occurred under another treatment. The registry's one listed arm is capecitabine plus lapatinib. Because a capecitabine-only arm is not listed, an effect of adding lapatinib cannot be estimated through a within-trial comparison. Historical comparisons, if any, would require additional assumptions and information not reported in this record.
The fact that the record describes an intended comparison in its brief summary does not create a control group in the recorded design. Statistical interpretation should follow the listed arms and analyses, rather than infer an unreported comparison. The study's single-group model and lack of masking also mean that the registry does not document a blinded, randomized contrast. Details about outcome assessment procedures are not reported in the registry record.
How should planning calculations be read?
In general, sample-size calculations are prospective planning tools. They describe how much information a proposed design might require under stated assumptions; they are not results from participants and do not establish the probability that a study has detected an effect. The registry's planning assumptions describe a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with an effect expressed as a fraction of an observed effect. Those are planning assumptions, not evidence that the completed study had two arms. The recorded trial is single-group, and no observed primary response effect is reported in the outcome record. Any sample-size illustrations should therefore not be interpreted as observed power or as a trial finding.
In general, over-dispersion occurs when variability in data is greater than a statistical model assumes. It can make standard errors too small if the model does not account for that extra variability. This concept is relevant when a model's distributional assumptions are not adequate; however, the registry does not report a fitted model or a variance analysis for this study. It would be speculative to claim that over-dispersion was assessed or adjusted for.
What does the safety information support?
Safety counts and percentages are descriptive observations, not a controlled estimate of comparative risk. Interpretation depends on the event definitions, exposure time, ascertainment, and whether events are counted by participant or by occurrence. The registry reports at-risk and affected figures for the group, but does not provide event-level timing, exposure-adjusted rates, or methods for adjudicating causality. The serious adverse-event percentages are presented as listed, without reconstructing counts from those percentages.
In sum, general statistical principles explain what the intended response endpoint could measure and what uncertainty measures would mean. They do not fill in the missing outcome data. The registry record does not report a primary efficacy estimate, inferential test, confidence interval, model, or detailed analysis plan, so no such result should be attributed to this study.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists a primary response-rate outcome and secondary aims concerning clinical benefit, time to disease progression, and overall outcome. The secondary-outcome text ends before the overall-outcome aim is fully described. The record notes two outcome measures but no analyses. It does not report a hierarchy among outcomes, a family-wise error strategy, an adjustment for multiple testing, or a plan for interpreting several endpoints. Whether multiplicity was addressed is not reported in the registry record.
The primary outcome itself was not assessable according to the registry because the trial ended early and insufficient data were collected. There is no reported response numerator, analysis denominator, estimate, or uncertainty interval. The record also does not explain whether outcome assessments were missing, whether participants withdrew, or whether any patients were excluded from analysis. Reasons for missing information and methods used to handle it are not reported in the registry record.
The analysis populations are not described. In general, an intention-to-treat population, a treated population, and an evaluable population can answer different questions, particularly when participants do not complete treatment or outcome assessment. The registry does not identify which population was intended or analyzed for the primary endpoint, and the absence of analyses prevents assessing whether the stated enrollment corresponds to any outcome analysis.
The record's early termination statement does not establish why the study stopped or whether a prespecified stopping rule was used. Interim analyses, stopping boundaries, and any statistical plan for early termination are not reported in the registry record. These omissions limit assessment of selection, missingness, and inferential uncertainty; they should not be filled in by assumption.
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 (Xeloda) + Lapatinib (Tykerb) | 3 | 11 | 27.3% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Capecitabine (Xeloda) + Lapatinib (Tykerb) | 1 of 11 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Capecitabine (Xeloda) + Lapatinib (Tykerb) | 11 of 11 |
Most frequent serious adverse event terms
| Event term | Organ system | Capecitabine (Xeloda) + Lapatinib (Tykerb) |
|---|---|---|
| Diarrhea | Gastrointestinal disorders | 2 of 11 |
| Sepsis | Infections and infestations | 1 of 11 |
| Death | Infections and infestations | 1 of 11 |
| Vomiting | Gastrointestinal disorders | 1 of 11 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Capecitabine (Xeloda) + Lapatinib (Tykerb) |
|---|---|---|
| Rash: hand-foot skin reaction | Skin and subcutaneous tissue disorders | 6 of 11 |
| Diarrhea | Gastrointestinal disorders | 5 of 11 |
| Nausea | Gastrointestinal disorders | 5 of 11 |
| Fatigue | General disorders | 4 of 11 |
| Vomiting | Gastrointestinal disorders | 3 of 11 |
| Anorexia | Metabolism and nutrition disorders | 3 of 11 |
| Mucositis - oral | Gastrointestinal disorders | 3 of 11 |
| Infection with normal ANC or Grade 1 or 2 neutrophiles | Infections and infestations | 2 of 11 |
| Infection with unknown ANC | Infections and infestations | 2 of 11 |
| Weight loss | Investigations | 1 of 11 |
Serious events with the highest arm-level rate: diarrhea (18.2%), sepsis (9.1%), death (9.1%), vomiting (9.1%).
The registry reports safety figures for the single capecitabine-plus-lapatinib group. Serious adverse events are recorded for 3 of 11 at risk. Other adverse events are recorded for 11 of 11 at risk, and deaths are recorded as 1. The listed serious adverse-event terms are diarrhea (18.2%), sepsis (9.1%), death (9.1%), and vomiting (9.1%). These are the reported entries; they should not be treated as a comparison with capecitabine alone, because no control group is listed.
These figures do not establish that the study treatment caused an event. A safety assessment also depends on definitions, how events were collected and classified, the period of exposure, and the handling of repeated events. Those details are not reported in the registry record. The listed percentages should be read as registry-reported values rather than recalculated or interpreted as exposure-adjusted rates.
The registry does not describe the timing, severity grading beyond the serious-event classification, duration, or outcome of individual events. The death entry is part of the posted safety information, but the record does not provide a cause or attribution. Because the study is small and single-group, these observations are descriptive and do not establish comparative safety.
12. What the Result Does, and Does Not, Mean
The main finding about the primary endpoint is that it cannot be assessed from the posted results. The registry explicitly states that early termination left insufficient data to assess the response rate by RECIST criteria. It does not report an observed response estimate or the information needed to judge its precision. This is not evidence of a particular response level; it is an absence of an assessable primary outcome in the record.
The study also does not answer the comparative question implied by its brief summary. The recorded design has one treatment group receiving capecitabine plus lapatinib, not a capecitabine-only comparison group. Without that control, differences attributable to the addition of lapatinib cannot be estimated from this trial. A single-group outcome description would not establish what would have happened to the same kind of patients under another treatment.
The safety entries document reported events in the combination arm, including serious adverse events, other adverse events, and a death. They are useful as observations from the registry, but they do not determine whether treatment caused those events or how safety compares with another regimen. The record lacks important context about event assessment and exposure.
In general, a small or incomplete study can leave wide uncertainty, but no precision estimate for the primary outcome is reported. The recorded enrollment is not a substitute for an evaluable outcome population. The registry does not report how many participants had usable response assessments or how missing information was handled.
The most defensible interpretation is therefore limited: the registry documents a terminated phase II, single-group investigation of the combination and insufficient data for its primary response-rate assessment. It does not establish efficacy, lack of efficacy, or a comparative treatment effect. Nor does the safety record establish comparative risk. Conclusions beyond these statements would require outcome and design information not reported in the registry record.
13. Why This Trial Matters Statistically
This trial illustrates why design details and outcome availability are essential to statistical interpretation. A title or summary may describe a comparison of treatments, but a comparative effect requires a design that includes both treatments in analyzable groups. The registry lists only the combination arm. That distinction changes the question the data could answer: a single group can describe observed outcomes, but it cannot provide a concurrent estimate of the difference between combination therapy and capecitabine alone.
The record also illustrates that naming a clinically meaningful endpoint does not mean it was measured with enough information to report a result. Response rate by RECIST criteria was the stated primary outcome, yet the registry says early termination left insufficient data to assess it. In that situation, no amount of statistical interpretation can recover a response estimate that is not recorded.
Reporting the analysis population and missing-data handling is important because enrollment and evaluability are not interchangeable. The registry records enrollment of 11 but does not explain which patients contributed to an endpoint analysis. Without that information, readers cannot assess the basis or precision of an efficacy estimate—even if one were presented.
Finally, safety counts from a single group should be understood as descriptive rather than comparative. The record reports events but does not provide the context needed to assess attribution or compare event risk across treatments. Together, these features make the study a useful example of how a trial's recorded design, completeness of results, and analysis details constrain what can be concluded.
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 limitations specific to this study restrict interpretation. The registry records a single-group design and lists no capecitabine-only comparator, despite the brief summary's description of an intended comparison. The posted design therefore does not support a within-trial comparative treatment-effect estimate.
The study was terminated early, and the registry states that insufficient data were collected to assess the primary response-rate endpoint. No response count, analysis denominator, estimate, confidence interval, or test result is reported. The reason for termination and whether stopping followed a prespecified rule are not reported in the registry record.
The registry records enrollment of 11 but does not describe the analysis population, the number with evaluable outcomes, treatment completion, follow-up completeness, or missing-data procedures. It also does not provide details of the planned statistical analysis, outcome assessment, or multiplicity handling. The secondary-outcome listing is incomplete, and no analyses are recorded.
Safety information is presented for the combination group, but the record does not specify event timing, duration, exposure-adjusted methods, or causal attribution. With no comparison group, these data cannot establish relative safety. The posted record also does not explain the circumstances of the recorded death.
These limitations concern both the study design and the information available in the registry. They make it inappropriate to infer an efficacy result, a lack of efficacy, or a comparative safety result from this record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Capecitabine (Xeloda) and Lapatinib (Tykerb) as First-line Therapy in HER2/Neu-positive Breast Cancer — NCT00496366.
- Registry record last updated 2017-03-21; status last verified 2017-03.
- Results first posted 2017-03-21.
- 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 describes a phase II, single-group study of capecitabine plus lapatinib as first-line therapy for advanced or metastatic HER2/Neu-overexpressing breast cancer. Allocation is listed as not applicable, masking as none, enrollment as 11, and status as terminated. The recorded start date is 2007-07-23, and the primary completion date is 2009-12-31.
The primary endpoint was response rate by RECIST criteria, with a stated timeframe of 2 years. The registry says early termination left insufficient data to assess it. One combination arm is listed; a capecitabine-only comparator is not. Safety observations are reported, but the registry does not provide a comparative safety analysis. The record lists no analyses and does not report the detailed statistical plan, analysis populations, or missing-data methods.