Capecitabine and Oxaliplatin in Patients With Advanced or Metastatic Pancreatic Adenocarcinoma: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Capecitabine and Oxaliplatin in Patients With Advanced or Metastatic Pancreatic Adenocarcinoma (NCT00585078), a na phase 2 study. The primary outcome is Response Rate.

2. Clinical Question

In statistical terms, the study asks how often a defined tumor response was observed in a selected group receiving the combination. It does not estimate a treatment effect relative to an assigned control group. The response analysis also depends on reaching the required assessment population: participants had to complete 2 cycles. That requirement matters when interpreting the result, because the primary analysis population is not simply everyone enrolled. The registry record does not report the number who completed the required cycles or explain how people without an evaluable response were handled.

3. Trial Design

The registry describes a completed phase 2, single-group study sponsored by Beth Israel Deaconess Medical Center. It lists pancreatic cancer as the condition and advanced or metastatic pancreatic adenocarcinoma as the setting of interest. Enrollment was recorded as 40. Allocation is listed as NA, and masking as none; the design is explicitly categorized as single-group. There is therefore no randomized treatment contrast in the registry record.

Participants received capecitabine and oxaliplatin together as CAPOX. The listed capecitabine schedule was 1,000 mg/m2 orally twice daily, days 1-14 in 21-day cycles. The registry notes that 500 mg tablets were used and doses were rounded to a dose that could be given with those tablets. The listed oxaliplatin dose was 130 mg/m2, but its administration description is incomplete in the registry record. Participants received a median of 2 cycles, with a range of 1-12.

Response was assessed by CT or MRI every two cycles, described as 42 days ±2 days, while participants were on treatment. The primary response analysis required completion of 2 cycles. These design details link the endpoint to both a scheduled imaging assessment and a defined response-evaluable population. The record does not explain how response assessments were handled when imaging was unavailable or did not occur on schedule.

The registry lists best response, overall survival, and progression-free survival as secondary outcomes, in addition to the primary response-rate endpoint. It records four outcome measures and no analyses. Numerical results for the primary endpoint and secondary outcomes are not reported in the registry record. The study start is listed as 2004-05 and primary completion as 2011-12; its status is completed. The registry record does not report a control regimen, a randomized allocation procedure, or a masking procedure.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The analysis dataset is comprised of response evaluable participants which required completion of two cycles of treatment.

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.

Population: The analysis dataset is comprised of enrolled patients.

6. Primary Endpoint

The registry lists the primary outcome as Response Rate, measured over Response was assessed by computed tomography (CT) or magnetic resonance imaging (MRI) every two cycles (42 days ±2 days) on treatment. Participants received a median (range) of 2 cycles (1-12) of CAPOX..

The primary endpoint, response rate, is defined as the proportion of participants achieving a complete response or partial response while on treatment. The criteria are based on RECIST 1.0. For target lesions, complete response means disappearance of all target lesions; partial response means at least a 30% decrease in the sum of longest diameters relative to the baseline sum. The record states that a response must be confirmed by repeat assessments performed no fewer than 4 weeks after response criteria are first met. A partial response or better also requires, at minimum, incomplete response or stable disease for non-target lesions and no new lesions.

Response rate is a binary endpoint at the participant level: each response-evaluable participant contributes a response classification, and the rate describes the proportion classified as having a complete or partial response. It is used to summarize tumor response under a prespecified measurement framework. In general, a standardized response definition can make imaging outcomes more consistent to classify across participants, although the registry record does not describe who reviewed images or whether assessment was independent.

The analysis population is defined as response-evaluable participants who completed 2 cycles. The registry describes imaging every two cycles, at 42 days ±2 days, and reports a median of 2 cycles (range 1-12). It specifies an 80% confidence interval as the endpoint’s dispersion measure, but the interval bounds and response estimate are not reported in the registry record. Without those results, the endpoint definition can be interpreted, but the observed response rate and its precision cannot be assessed.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a single-group design estimate?

A single-group study records outcomes among participants receiving the study regimen. Its outcome summaries can describe the observed experience in that enrolled and analyzed population. Because the registry categorizes this study as single-group and lists allocation as NA, it does not provide a randomized comparison against another treatment or a control condition. A difference from an external benchmark, if someone were to make one, would not be a randomized treatment contrast and would require information not reported in the registry record.

Masking is listed as none. Masking can reduce the influence of knowledge about treatment assignment on some aspects of assessment or care. In a single-group study there is no listed assigned comparison to conceal, and the record does not specify whether response images were reviewed independently or by assessors unaware of other information. That assessment detail is not reported in the registry record.

How should a response proportion be understood?

General explanation: a response proportion is formed by classifying participants according to whether they meet the response definition, then expressing the number meeting it relative to the analysis population. It summarizes the frequency of a defined event in that population; it is not itself a comparison with what would have happened under a different treatment. For this study, the endpoint includes complete and partial response according to RECIST 1.0 and the stated confirmation requirements.

The endpoint is described as a proportion of response-evaluable participants, and response evaluability requires completion of 2 cycles. This population restriction affects the meaning of the estimate: it would describe participants meeting the response-evaluation requirement, not automatically every enrolled participant. The number in that analysis population and the response numerator are not reported in the registry record, so the proportion cannot be reconstructed from the registry information.

What does the confidence interval add?

The record names an 80% confidence interval as the measure of dispersion for the primary endpoint. General explanation: a confidence interval gives a range of estimates compatible with the observed data under a particular statistical method. Its width reflects statistical precision, which is influenced by the amount of information and the variability in the data. It does not capture every source of uncertainty, such as selection into the analysis population or limitations of a single-group design.

The confidence-interval limits are not reported in the registry record. No interval can therefore be interpreted for this endpoint, and no precision claim can be made from its stated confidence level alone. A confidence level describes the method’s repeated-sampling properties in general; it does not supply the missing endpoint estimate or interval bounds.

How does the planned sample-size illustration differ from the study design?

The sample-size material is described as a planning illustration based on the observed effect, rather than as the trial’s own design justification. Its stated assumptions are a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect to detect expressed as a fraction of the observed effect. This is a hypothetical planning framework and is not the design recorded for the study, which is single-group.

The illustration is not observed power and does not show that the study had a particular probability of detecting an effect. Planning calculations describe what sample size might be needed under assumptions; they do not change the design or create a randomized comparator. The registry record does not report its own sample-size justification, statistical plan, or any interim analyses. Numerical outputs for the planning illustration are not reported in the registry record information.

General explanation: over-dispersion occurs when observed variability exceeds what a chosen statistical model assumes. When present, a model that ignores it can understate uncertainty. No over-dispersion assessment or model for the response estimate is reported in the registry record, so this is a general methodological consideration rather than a claim about the analysis used in this study.

What can be inferred from the listed outcomes?

The registry lists best response, overall survival, and progression-free survival as secondary outcomes. Naming an outcome does not specify its full statistical definition. For time-to-event outcomes, interpretation commonly depends on the time origin, event definition, censoring rules, and analysis method. Those details and numerical results are not reported in the registry record. The record also does not report a statistical analysis plan, an adjustment approach for multiple outcomes, or model details for the listed endpoints.

These limitations distinguish the endpoint rules that are explicitly recorded from analytical choices that remain unknown. They also prevent a quantitative reassessment of the primary or secondary outcomes. No unadjusted recalculation is available from the registry information.

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("CAPOX")
n      <- c(24)
events <- c(0)
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  CAPOX  24  0  0.0  0.0  14.2  0.0  13.8  0.1  13.7

11. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary endpoint, response rate, and secondary outcomes of best response, overall survival, and progression-free survival. Considering multiple outcomes can increase the chance of at least one apparently notable finding when each is tested separately. General statistical practice may address this through a prespecified hierarchy, adjustment, or careful interpretation, but the registry record does not report a multiplicity strategy or statistical analysis plan. No claim can be made about whether any adjustment was used.

The registry describes the response analysis population as response-evaluable participants who completed 2 cycles. This is an explicit population condition, but the number meeting it is not reported in the registry record. The record also does not describe how missing imaging, incomplete follow-up, withdrawal, or other unavailable outcome information was handled. Missing-data assumptions and sensitivity analyses are not reported in the registry record.

Enrollment is recorded as 40, while the adverse-event listing identifies 36 participants at risk for the serious and other event categories. The registry record does not explain these population counts or indicate that they correspond to the primary efficacy population. They should therefore not be treated as interchangeable denominators.

The record lists four outcome measures and no analyses. Numerical results and analysis details for the listed endpoints are not reported in the registry record. Without a stated multiplicity plan, missing-data approach, or full analysis-population accounting, the endpoint definitions alone do not establish how all potential outcome information entered the analyses.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: fatigue (19.4%), nausea (16.7%), diarrhea w/o prior colostomy (13.9%), vomiting (11.1%), hemoglobin (8.3%).

The safety listing is for the CAPOX group. It records 36 participants at risk for serious adverse events and 18 affected. For other adverse events, it records 36 at risk and 34 affected. It also lists 0 deaths. These are counts in the registry record; they are not comparative estimates, because the study has no concurrent control group.

The most frequently listed serious-event terms are fatigue (19.4%), nausea (16.7%), diarrhea w/o prior colostomy (13.9%), vomiting (11.1%), hemoglobin (8.3%), and abdomen, pain (8.3%). These percentages describe the recorded serious-event terms. The registry does not report a safety observation window or further details about event grading, attribution, timing, or whether participants could contribute more than one event term. The displayed terms should not be interpreted as a complete account of all adverse events.

General explanation: a participant count with at least one event and a list of event terms answer different questions. A participant may have more than one type of event, so term counts or percentages should not be added to estimate a total. The record does not provide a randomized comparison that would support attributing differences in event occurrence to CAPOX relative to another regimen. The safety figures describe what was recorded in this study and do not by themselves establish causation.

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

The registry record establishes that this was a completed phase 2, single-group study of capecitabine and oxaliplatin in advanced or metastatic pancreatic adenocarcinoma. It records the primary endpoint as response rate, defines response using RECIST 1.0, and specifies that the response-evaluable population had to complete 2 cycles. It also describes the imaging schedule and lists secondary outcomes.

What the record does not establish is the observed response rate. It does not report a response count, an estimate, or the bounds of the stated 80% confidence interval. Nor does it report numerical results for best response, overall survival, or progression-free survival in the information. The endpoint definition therefore explains what the study intended to measure, not what its result was.

The single-group design means that recorded outcomes are not a randomized comparison with another regimen or control. A descriptive outcome in participants receiving CAPOX cannot, on its own, quantify what would have occurred under an alternative. This design also does not resolve potential influences related to selection, follow-up, or the requirement to complete 2 cycles for response evaluation.

The safety record lists event counts and serious-event terms for the CAPOX group. Those figures describe recorded events in the listed safety population; they do not establish that the regimen caused every event, and without a control group they do not measure relative risk against another treatment. The registry does not report the safety observation window or detailed event assessment methods.

Accordingly, the recorded information supports a careful description of the trial’s design, eligibility for response evaluation, endpoint criteria, and listed safety counts. It does not support a conclusion about the magnitude or precision of tumor response, survival outcomes, or comparative benefit and harm. These limits reflect missing outcome results and the non-comparative design, rather than an interpretation of an unreported result.

14. Why This Trial Matters Statistically

This trial illustrates why endpoint definitions and analysis populations belong beside any reported clinical outcome. Response rate is not merely a label: the registry specifies RECIST 1.0 criteria, confirmation requirements, requirements for non-target lesions, and the absence of new lesions. It also restricts the primary analysis population to participants who completed 2 cycles. Each detail affects what a response estimate would mean.

The record also makes the design distinction clear. A single-group study can describe outcomes among treated participants, but it does not provide the randomized contrast needed to directly compare the regimen with a control. This matters when readers encounter response or safety figures: a percentage from a treated group is not, by itself, an estimate of a treatment difference.

Precision is another essential part of interpretation. The primary endpoint lists an 80% confidence interval, but no estimate or interval bounds are reported in the registry information. Without these, readers cannot assess the size or precision of the response result. Naming a statistical measure is not a substitute for reporting its value.

Finally, the record shows the importance of distinguishing a trial’s own design from a later planning illustration. The described sample-size illustration assumes equal allocation between two arms, while the registered study is single-group. Planning calculations based on hypothetical assumptions cannot create a control group or serve as observed power. Taken together, these points demonstrate how design, endpoint rules, population definitions, and complete reporting shape the statistical meaning of a clinical trial.

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 registry record does not report the primary response count, response-rate estimate, or confidence-interval bounds. It also does not report numerical results for the listed secondary outcomes. This prevents evaluation of the magnitude and precision of the study’s efficacy outcomes from the recorded information.

The single-group design has no concurrent randomized comparator. Outcomes in participants receiving CAPOX can be described, but the design does not estimate a randomized difference against another treatment. Allocation is listed as NA and masking as none. The record does not say whether response imaging was assessed independently or under blinded review.

The primary analysis population is limited to response-evaluable participants who completed 2 cycles, but its size is not reported. Although enrollment is 40, the registry does not explain how many participants entered the response analysis or how missing or unevaluable assessments were handled. The safety listing uses 36 participants at risk, and the relationship between that safety population and the response population is not reported.

Other analytical details are also not reported in the registry record: the statistical analysis plan, multiplicity approach, missing-data assumptions, sample-size justification for the study itself, and interim analyses. For the secondary time-to-event outcomes, the record information does not give endpoint definitions, time origins, censoring rules, or estimates. These omissions limit reproducibility and interpretation.

The treatment description includes the capecitabine schedule and oxaliplatin dose, but the oxaliplatin administration details are incomplete in the registry record. Safety reporting lists event counts and terms without an observation window or detailed assessment information. These limits should be kept distinct from the absence of efficacy results: they constrain interpretation but do not indicate what the unreported outcomes were.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Capecitabine and Oxaliplatin in Patients With Advanced or Metastatic Pancreatic Adenocarcinoma — NCT00585078.
• Registry record last updated 2017-04-10; status last verified 2017-02.
• Results first posted 2017-04-10.
• 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

NCT00585078 is a completed phase 2, single-group study sponsored by Beth Israel Deaconess Medical Center. It enrolled 40 participants with advanced or metastatic pancreatic adenocarcinoma and examined capecitabine plus oxaliplatin (CAPOX). The primary endpoint was response rate under RECIST 1.0 among response-evaluable participants, defined as those who completed 2 cycles. Imaging was scheduled every two cycles, at 42 days ±2 days.

The registry record lists best response, overall survival, and progression-free survival as secondary outcomes. It describes an 80% confidence interval for the primary endpoint but does not report the response estimate or interval bounds in the information. Safety counts are listed for the CAPOX group, including 18 of 36 participants affected by serious adverse events and 34 of 36 affected by other adverse events; 0 deaths are listed. There is no concurrent control group, and the registry record does not report numerical results for the efficacy outcomes.