Sorafenib, Gemcitabine, and Capecitabine in Treating Patients With Unresectable and/or Metastatic Kidney Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Sorafenib, Gemcitabine, and Capecitabine in Treating Patients With Unresectable and/or Metastatic Kidney Cancer (NCT00121251), a na phase 1, phase 2 study. The primary outcome is Objective Response for BAY 43-9006 in Combination With Gemcitabine and Capecitabine Evaluated by the Response Evaluation Criteria in Solid Tumors (RECIST).

2. Clinical Question

The registry frames this Phase I/II study as investigating side effects and the best dose of the combination, as well as how it works in patients with unresectable and/or metastatic kidney cancer. The primary endpoint is objective response, rather than a direct comparison of the combination against another treatment. The listed response timeframe is up to 9 years.

The record also names median months of progression-free survival and the number of participants who survived as secondary outcomes. Their results are not reported in the registry record. The objective-response result is also not reported in the registry record, so the record does not establish how many participants met the response definition. Without a comparator group, the study cannot estimate a between-group treatment effect. Its design instead describes outcomes among participants receiving the combination. The registry record does not report a separate statistical plan or details of how the response outcome was analyzed.

3. Trial Design

This is a Phase I/II, single-group clinical trial sponsored by the National Cancer Institute. The registry record lists enrollment of 17 and marks the study as completed. The recorded start date is 2005-06-03, and the primary completion date is 2017-03-14. Allocation is listed as not applicable, and masking is listed as none.

Participants in the listed group received sorafenib by mouth twice daily on days 1-21, gemcitabine intravenously on days 1 and 8, and capecitabine by mouth twice daily on days 1-14. Treatment repeats every 21 days for at least 3 courses in the absence of unacceptable toxicity or disease progression. These details describe the regimen in the registry record; dose amounts are not reported in the registry record.

The registry summary states that the trial studied side effects and the best dose, in addition to how the combination performed. The record does not report separate phase-specific results, dose-escalation details, or a selected dose. Nor does it describe a control arm. A single-group design can describe outcomes observed among treated participants, but it does not provide a direct randomized comparison with another treatment or with an untreated group.

The listed conditions are recurrent renal cell carcinoma and stage III and stage IV renal cell cancer. The record does not provide further eligibility details, participant characteristics, or a description of the analysis population. It therefore cannot establish from the record alone how closely the enrolled participants matched any narrower clinical subgroup.

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

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 Objective Response for BAY 43-9006 in Combination With Gemcitabine and Capecitabine Evaluated by the Response Evaluation Criteria in Solid Tumors (RECIST), measured over Up to 9 years.

The primary endpoint is objective response for BAY 43-9006, the name used in the endpoint title for sorafenib, in combination with gemcitabine and capecitabine. It is recorded as a count of participants and assessed by MRI using RECIST v1.0 criteria for target lesions. The stated timeframe is up to 9 years.

Under the definition in the record, 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. Objective response combines complete and partial response. The endpoint therefore classifies participants according to whether their measured target lesions meet either response category; it is not a measure of survival or symptom change.

Response criteria provide a standardized way to describe changes in measured lesions. A count can communicate how many participants met the definition, while interpretation also depends on how many participants were assessed and how missing or unevaluable assessments were handled. Those details, along with the endpoint result itself, are not reported in the registry record. The definition alone does not show how many participants responded or how precisely that count estimates response in a broader population.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes a count-based primary endpoint: the number of participants with an objective response. This is a binary classification at the participant level: a participant either meets the complete- or partial-response definition or does not. The recorded endpoint parameter is a participant count, not a continuous measurement such as the average change in lesion size. The registry record does not report the observed count or a statistical analysis for this endpoint.

What does a response count represent?

In general, a response count is interpreted alongside the number of participants assessed. The count describes the observed trial group, while a proportion can express the count relative to an eligible analysis denominator. The denominator is essential: it identifies which participants were included in the calculation and how participants without an evaluable assessment were treated. No primary outcome denominator or analysis-population definition is reported in the registry record, so a response proportion cannot be read from it.

In general, uncertainty around a binary outcome can be described with a confidence interval. A confidence interval conveys the range of values compatible with the observed data under the method used; it is not a guarantee that the true value falls within that range. Its width depends on the amount of information and the observed outcome pattern, as well as the interval method. No confidence interval for objective response is reported in the registry record. No numerical interval should therefore be inferred from the enrollment figure alone.

How does the response definition work?

The registry uses RECIST v1.0 for target lesions assessed by MRI. Complete response requires disappearance of all target lesions; partial response requires at least a 30% decrease in the sum of the longest diameters of target lesions. Objective response is the combination of those categories. This threshold-based classification makes the endpoint interpretable as a participant count, but it does not report the size or duration of change for every participant. The record does not describe independent review, confirmation requirements, or how assessments were handled when they could not be evaluated.

What does the design allow statistically?

The study is listed as single-group, with allocation not applicable and masking none. In general, a single-group study can estimate outcomes in the group studied if the outcome data and analysis are reported. It does not generate a randomized between-group contrast. Without a concurrent comparator, an observed outcome cannot by itself distinguish treatment effects from the natural course of disease, participant selection, or other influences. The registry record does not report an adjusted analysis or a statistical plan that would address these issues.

Phase I/II trials may include dose and activity questions, but the registry record does not report the phase-specific methods, dose-finding rules, or dose-selection analysis for this study. The summary says the trial studied side effects and the best dose, but that statement is not a report of the method used or its findings. The dose amounts are not reported in the registry record.

How should planning illustrations be understood?

The record describes planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It states that time-to-event illustrations use a total number of events under the Schoenfeld method, while other illustrations use participants per arm. These assumptions describe planning calculations, not the design of the listed single-group trial. No numerical illustration results or observed effect are reported in the registry record. Such planning values are not observed power and should not be presented as though the trial enrolled a randomized two-arm comparison.

In general, a sample-size calculation asks how much information a planned study would need under specified assumptions. It does not establish that a study actually had that information, nor does it indicate the probability that a treatment works. The calculations depend on inputs such as the effect targeted and the analysis framework. If the assumptions do not match the actual study design, the result is not a direct description of this trial's design or evidence.

What cannot be assessed from the record?

The registry reports no analyses in its analysis count. It does not report a primary response estimate, uncertainty interval, hypothesis test, adjustment for covariates, or multiplicity procedure. It also does not report missing-data handling or the population included in each outcome analysis. These omissions mean readers cannot assess the analysis choices, reproduce an efficacy estimate, or evaluate how robust the result was to alternative choices.

General statistical principles still help identify what a complete report would need to make clear: the outcome definition, assessed population, denominator, handling of missing measurements, analysis method, and estimate with uncertainty. For survival outcomes, reporting would ordinarily also clarify the time origin, censoring, and analysis population. The registry record names progression-free survival and overall survival but does not provide these details or their results. No additional assumptions about the statistical plan can be made from the endpoint names alone.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Sorafenib + Gemcitabine + Capecitabine")
n      <- c(17)
events <- c(5)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Sorafenib + Gemcitabine + Capecitabine  17  5  29.4  10.3  56.0  13.3  53.1  13.3  53.5

11. Multiplicity, Missing Data and Analysis Populations

The record lists 3 outcome measures and names objective response as the primary outcome. It also names median months of progression-free survival and the number of participants who survived as secondary outcomes. The results of these outcomes are not reported in the registry record. A multiplicity method for interpreting several outcomes is also not reported in the registry record.

In general, when a study evaluates several outcomes or makes several statistical comparisons, the chance of a misleading positive finding can increase if each is interpreted independently. A prespecified testing hierarchy or adjustment can address this concern, but the appropriate approach depends on the study question and analysis plan. The registry record does not report whether such a plan was used. The absence of a reported method should not be taken to mean that an adjustment was or was not performed.

Missing-data methods and analysis populations are not reported in the registry record. Although enrollment is recorded as 17, the record does not specify how many participants had an evaluable primary endpoint, whether all enrolled participants were included in the outcome analysis, or how participants without an assessment were handled. It also does not describe exclusions or the treatment of incomplete follow-up for the survival outcomes. These details matter because outcome counts and estimates depend on who is included and how unavailable information is addressed.

The registry record does not report interim analyses, stopping rules, or a statistical analysis plan. Those features should not be inferred from the Phase I/II designation or from the listed endpoints. Without reported results and analysis details, the record does not permit assessment of multiplicity control, missing-data sensitivity, or the consistency of the analyzed populations across outcomes.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

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

Most frequent non-serious adverse event terms

The adverse-event record lists 17 participants at risk for serious adverse events and 0 affected. For the other adverse-event category, it lists 17 at risk and 5 affected. The same group entry lists 11 deaths. These are recorded counts; they should not be converted into percentages or combined into a new total.

The serious-event terms list is empty. That means the registry record gives no serious-event terms to describe, not that the record establishes the absence of every possible safety concern. The other affected count is shown under a separate category, and the registry entry does not provide event terms in the registry record for this summary. The record does not say whether participants could contribute to more than one category, so the counts should not be added together.

The deaths entry is not, by itself, an attribution statement. The registry record does not provide causes, timing, or a relationship to study treatment for those deaths. Nor does the count establish a survival outcome estimate: overall survival is separately listed as a secondary outcome, and its result is not reported in the registry record. These safety fields are therefore best read as limited event counts with important contextual details absent.

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

The record establishes that a Phase I/II, single-group study evaluated a combination of sorafenib, gemcitabine, and capecitabine in advanced renal cell carcinoma. It specifies an objective-response definition based on RECIST v1.0 and MRI assessment of target lesions. It also records selected safety counts and the study's enrollment and status. Those details describe the study and its planned clinical question.

The record does not report the primary response count, progression-free survival result, or overall survival result. It therefore does not show how many participants met the response definition, how long participants lived without progression, or the survival outcome. It also does not provide uncertainty estimates that would convey the precision of any efficacy estimate. The absence of reported outcome results is not evidence that the outcomes were favorable or unfavorable.

Even if an outcome estimate were available, a single-group design would describe outcomes in the treated participants rather than provide a randomized comparison. It could not alone show what would have happened to comparable participants receiving another treatment. The record also lacks important analysis details, including the assessed population and missing-data methods, which would be necessary to interpret an endpoint estimate fully.

The adverse-event counts do not establish that a listed event was caused by the regimen. The record does not give serious-event terms or the context needed to interpret the deaths entry. In general, safety interpretation depends on event definitions, timing, attribution, follow-up, and the population observed; those details are not reported in the registry record.

Accordingly, the registry supports a descriptive account of the study design, regimen, endpoint definition, and recorded safety fields. It does not support a conclusion about the combination's efficacy, comparative benefit, or causal safety effects. These distinctions are important: a trial's research question, an outcome definition, and an observed result are separate pieces of evidence.

14. Why This Trial Matters Statistically

This trial is statistically notable for the gap between a clearly stated clinical endpoint and the outcome information available in the registry record. Objective response is defined using RECIST v1.0 and MRI assessment, with complete and partial response criteria stated. Yet the response count and its denominator are not reported. Readers therefore have a definition but not an estimate to evaluate.

The single-group design also makes the distinction between describing outcomes and estimating comparative effects especially important. A count among participants receiving the regimen would be a descriptive result for that study group. It would not be a randomized contrast against another treatment. This distinction is central to interpreting what kinds of claims a study design can support, independent of whether a result appears promising.

The record also illustrates why safety fields require careful reading. It lists serious adverse events, other affected participants, and deaths in separate entries, while providing little context about event terms, timing, or attribution. Statistical interpretation should preserve those distinctions rather than collapse counts into an unsupported overall claim.

Finally, the planning assumptions described in the record do not match the listed single-group design: they refer to equal allocation between hypothetical arms. Planning illustrations can be informative only when their assumptions are understood, and they do not substitute for observed trial results. The record does not report the illustration values or an efficacy analysis. Together, these features make transparent reporting of results, denominators, uncertainty, and analysis populations particularly important for evaluating this study.

15. 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 limitation for interpreting this specific trial is that the registry record does not report the primary objective-response result. It also does not report results for the named secondary outcomes, median months of progression-free survival and overall survival. Without outcome estimates, there is no basis in this record for assessing the magnitude or precision of observed efficacy findings.

The single-group design lacks a listed comparator, so it cannot provide a direct randomized comparison. The registry record also lists no masking. It does not report the number of participants assessed for response, the analysis population, missing-data handling, or the rules for unevaluable imaging. These gaps make it difficult to know how endpoint data would have been incorporated into an analysis.

Further limitations specific to the record include the absence of dose amounts, dose-selection results, phase-specific methods, and a statistical analysis plan. Although the trial summary describes studying side effects and the best dose, the methods and findings for those aims are not reported in the registry record. The registry also does not provide participant characteristics or eligibility details beyond the listed conditions and disease descriptions.

The safety information is limited to counts. The record provides no serious-event terms, and it does not report the timing, causes, or treatment attribution of deaths. The other adverse-event category is not described in further detail. These limitations prevent a fuller assessment of the pattern and context of safety events from the registry entries alone.

These are limitations of what the registry record reports; they do not establish whether additional information exists elsewhere. No unreported methods or results should be assumed.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Sorafenib, Gemcitabine, and Capecitabine in Treating Patients With Unresectable and/or Metastatic Kidney Cancer — NCT00121251.
• Registry record last updated 2021-04-06; status last verified 2021-03.
• Results first posted 2021-04-06.
• 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.

19. Record Summary

The registry record describes a completed Phase I/II, single-group study sponsored by the National Cancer Institute, with enrollment of 17. It lists sorafenib, gemcitabine, and capecitabine for patients with unresectable and/or metastatic kidney cancer. Allocation is not applicable, and masking is none.

The primary outcome is objective response by RECIST v1.0 for target lesions assessed by MRI, with a timeframe of up to 9 years. The response result and the named secondary-outcome results are not reported in the registry record. The record lists 0 serious adverse events among 17 at risk, 5 affected under the other adverse-event category among 17 at risk, and 11 deaths; event context and attribution are not reported. Analysis details, missing-data methods, and the analysis populations are also not reported in the registry record.