Gemcitabine and Erlotinib Before and After Surgery in Treating Patients With Pancreatic Cancer That Can Be Removed by Surgery: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Gemcitabine and Erlotinib Before and After Surgery in Treating Patients With Pancreatic Cancer That Can Be Removed by Surgery (NCT00733746), a na phase 2 study. The primary outcome is Overall Survival at 2 Years.

2. Clinical Question

The clinical question is about the proportion of eligible participants meeting a specified survival status at a fixed time point after registration. It is not a randomized comparison of the drug-and-surgery sequence against another treatment or against surgery alone. The record identifies a planned sequence involving preoperative therapy, surgery, and postoperative therapy, but it does not provide a reported primary-endpoint result with which to describe the observed survival proportion or its precision.

The registry lists resection rate, relapse/progression-free survival, response rate, and participants experiencing Grade 3 or higher adverse events among the secondary outcomes. These outcomes address different aspects of the treatment course and are not substitutes for the primary endpoint. The registry record lists 5 outcome measures in total; the additional measure is not identified in the available outcome list. No comparative conclusion can be drawn from these records because there is no separate control group and the primary survival estimate is not reported.

3. Trial Design

This was a phase II, single-group study sponsored by the Alliance for Clinical Trials in Oncology. The registry lists enrollment of 123 and describes the study population as patients with pancreatic cancer that could be removed by surgery. The official title identifies the disease as operable pancreatic adenocarcinoma. The study is marked completed; its recorded start is 2009-04 and its primary completion is 2015-11.

The intervention sequence was neoadjuvant gemcitabine and erlotinib, pancreatectomy, and postoperative gemcitabine and erlotinib. The registry describes gemcitabine as intravenous and erlotinib as oral, and gives some details of the preoperative schedule. The postoperative regimen details are not reported in the registry record. The study was unmasked, and allocation is recorded as NA. These design features mean that the registry does not describe randomized assignment or a separate comparison arm.

The primary endpoint population is narrower than the general study population: patients had to meet eligibility criteria, complete neoadjuvant therapy, and undergo protocol surgery with R0 or R1 resection. The stated primary outcome is the proportion alive at two years from registration. The registry record does not give the number included in that endpoint analysis or a numerical survival result.

A single-group phase II design can describe what happened among participants treated under the study regimen, but it does not isolate the effect of the regimen from other influences in the way a suitable concurrent comparison can. Differences between the enrolled population and the primary-endpoint population also matter when interpreting results: the endpoint is defined for a selected group meeting treatment and surgery conditions, not automatically for every enrolled participant. Reasons that participants may not have met the primary-endpoint definition are not reported in the registry record.

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: 123 patients enrolled to this study. 4 patients cancelled prior to treatment and were not included in any analysis.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: All patients meeting the eligibility criteria who completed neoadjuvant therapy and underwent protocol surgery with R0 or R1 resection were evaluated for the primary endpoint.

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: All patients that started protocol treatment were included in this analysis.

6. Primary Endpoint

The registry lists the primary outcome as Overall Survival at 2 Years, measured over At 2 years post-registration.

The primary endpoint is overall survival at two years, expressed as the proportion of patients alive at two years from registration. The registry defines a treatment success as an evaluable patient alive at that time. Its specified analysis population consists of eligible patients who completed neoadjuvant therapy and underwent protocol surgery with R0 or R1 resection. The endpoint timeframe is two years post-registration.

A fixed-time survival proportion gives a direct description of the share of the defined population alive at a particular follow-up point. It is different from a time-to-event summary that uses the timing of events throughout follow-up. The registry specifies a 95% confidence interval as the measure of dispersion. In general, a confidence interval conveys uncertainty around an estimated quantity: a narrower interval indicates greater precision, while a wider interval indicates less precision, under the assumptions of the method used.

The record does not report the observed proportion, its confidence interval, or the number evaluated for this endpoint. Consequently, the size and precision of the primary result cannot be described from the registry entry. The endpoint definition alone does not establish how many participants were alive at the specified time or what the study found.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The study is described as phase II and single-group. In general, a phase II study can provide information about outcomes under a treatment approach, but the label alone does not specify the statistical design, decision thresholds, or intended interpretation. Those details are not reported in the registry record. The record also lists allocation as NA and masking as none. With no separate comparator group, the study is not a randomized comparison between treatment strategies.

What does the primary endpoint estimate?

The endpoint is a proportion: the share of the defined analysis population alive at two years from registration. The registry calls it overall survival at two years and defines success as being alive at that time. A proportion is a binary outcome at the specified time point: each evaluable participant either meets the success definition or does not. The recorded unit is proportion of patients, and the stated dispersion measure is a 95% confidence interval.

In general, an estimate is the value calculated from observed data, while a confidence interval communicates uncertainty around that estimate under a statistical model. The interval is not a guarantee that the true value lies within its endpoints, and it does not describe individual outcomes. Here, neither the estimate nor the interval is reported in the registry record, so their magnitude and precision cannot be interpreted.

Who is included in the primary analysis?

The specified population includes patients meeting eligibility criteria who completed neoadjuvant therapy and underwent protocol surgery with R0 or R1 resection. This definition is important because it does not simply say that every enrolled participant contributes to the primary endpoint. In general, analysis populations defined by post-registration treatment or surgery milestones can differ from the enrollment population. The size of this primary analysis group and the handling of patients who did not meet the definition are not reported in the registry record.

What do the safety counts describe?

The registry reports 119 at risk and 37 affected for the serious adverse-event category. It reports 119 at risk and 118 affected for the other adverse-event category. These are counts in the registry's posted safety record, not measures of the primary survival endpoint. The record lists selected serious event terms with percentages. In general, a count of participants affected and a percentage associated with an event term answer different descriptive questions, and interpretation depends on the event definitions, observation period, and denominator used. Additional details about attribution, exposure periods, and the rules for counting repeated events are not reported in the registry record.

How should the planning illustrations be understood?

The stated sample-size assumptions describe planning illustrations computed from the observed effect, not the trial's own design. They specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation, with the effect to detect expressed as a fraction of the observed effect. For time-to-event outcomes, the stated illustrations give a total number of events using the Schoenfeld approach; for other outcomes, they give participants per arm.

Those assumptions are not a description of this single-group trial's allocation or a reconstruction of its protocol. In particular, equal allocation between two arms is an assumption for a hypothetical planning calculation, not evidence that this study randomized participants between arms. Any sample sizes generated under such assumptions are planning illustrations only, never observed power. The registry does not report a sample-size justification or the trial's own statistical design assumptions. The numerical planning outputs are not stated in the information available for this analysis.

What can be inferred from the analysis record?

The registry lists 5 outcome measures and 0 analyses. The outcome list names the primary endpoint and four secondary outcomes: resection rate, relapse/progression-free survival, participants experiencing Grade 3 or higher adverse events, and response rate. Listing an outcome indicates that it was included in the record; it does not itself provide a result. No p-value, effect estimate, confidence interval, or analysis method for these outcomes is reported in the registry information.

In general, an analysis method determines how observed data are converted into an estimate and how uncertainty is quantified. The method used for the primary proportion, handling of incomplete follow-up, and any planned adjustment or subgroup analysis are not reported in the registry record. Without those details and the result itself, the endpoint definition should not be mistaken for a complete statistical analysis.

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("Neoadjuvant Therapy + Surgery + Adjuvant Therapy")
n      <- c(74)
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  Neoadjuvant Therapy + Surgery + Adjuvant Therapy  74  0  0.0  0.0  4.9  0.0  4.9  0.0  4.8

11. Multiplicity, Missing Data and Analysis Populations

The registry names one primary endpoint, overall survival at two years, and lists 5 outcome measures in total. The named secondary outcomes are resection rate, relapse/progression-free survival, participants experiencing Grade 3 or higher adverse events, and response rate. The record does not state how many hypotheses were tested or how statistical testing across outcomes was handled. Multiplicity procedures, including any adjustment for testing several outcomes, are not reported in the registry record.

The registry lists 0 analyses, and numerical estimates for the primary and secondary outcomes are not reported in the information available for this analysis. This means there is no posted analysis result from which to assess test statistics, confidence intervals, or whether any multiplicity approach was applied. The existence of several registered outcomes does not by itself show that every outcome was tested or that a particular adjustment was used.

The primary analysis population is defined by eligibility, completion of neoadjuvant therapy, and surgery with R0 or R1 resection. The number of participants in that group is not reported in the registry record. The record also does not describe how missing endpoint information, loss to follow-up, or other incomplete observations were handled. No imputation method, censoring rule, or sensitivity analysis is reported.

In general, missing-data methods matter because the interpretation of an estimate can depend on who has observed outcome information and why other information is absent. The registry record does not provide enough detail to assess that issue for the primary endpoint. The distinction between the enrollment count and the safety record's at-risk count should also be preserved; the reason they differ is not reported and cannot be inferred from these figures.

12. 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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: aspartate aminotransferase increased (7.6%), alanine aminotransferase increased (6.7%), biliary tract infection (5.0%), bilirubin increased (5.0%), hemoglobin decreased (4.2%).

The posted safety record describes one group titled Neoadjuvant Therapy + Surgery + Adjuvant Therapy. It reports 119 participants at risk and 37 affected in the serious adverse-event category. For other adverse events, it reports 119 at risk and 118 affected. These categories should be kept distinct: the serious-event count is not the total count for all adverse events.

The record lists the leading serious adverse-event terms with percentages: aspartate aminotransferase increased, 7.6%; alanine aminotransferase increased, 6.7%; biliary tract infection, 5.0%; bilirubin increased, 5.0%; hemoglobin decreased, 4.2%; and fatigue, 4.2%. These are event-term figures in the registry record, not comparative estimates against another treatment group.

In general, adverse-event counts describe events recorded under the study's reporting definitions; they do not, on their own, establish that treatment caused an event. The registry information does not report details about attribution, observation periods, or whether multiple events in one participant are represented in these term percentages. The reason the at-risk count differs from enrollment of 123 is not reported in the registry record.

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

The registry record establishes that this was a phase II, single-group study of gemcitabine and erlotinib administered before and after surgery for operable pancreatic adenocarcinoma. It also defines the primary question: the proportion of the specified analysis population alive at two years from registration. These details describe the study's design and intended endpoint; they do not state the observed answer.

The primary survival estimate and its 95% confidence interval are not reported in the registry record. Therefore, the magnitude and precision of the primary outcome cannot be assessed from this entry. The record also does not provide numerical results for the listed secondary outcomes. No conclusion about the direction or size of an effect should be drawn from outcome names or definitions alone.

Because the study is single-group, the posted information does not offer a randomized control comparison. Outcomes among participants in this study cannot, from these data alone, establish what would have happened to comparable participants under another strategy. This is a limitation of the design for comparative interpretation, not evidence for or against any particular treatment effect.

The safety information does give descriptive counts and event-term percentages. These figures can be reported as posted, but they do not establish causation or a difference relative to another group. The record also does not explain the difference between enrollment and the at-risk safety denominator.

In general, statistical interpretation requires the estimate, its uncertainty, the analysis population, and sufficient information about how the data were handled. The registry supplies an endpoint definition and some safety figures but does not report the primary estimate, confidence interval, or analysis details needed for a fuller assessment. The results should therefore be described as unavailable in the registry record rather than inferred from the study design.

14. Why This Trial Matters Statistically

This study illustrates why the distinction between a registered endpoint and a reported result matters. Overall survival at two years is defined clearly as the proportion of evaluable patients alive at two years from registration. However, without the observed proportion and its 95% confidence interval, readers cannot assess either the size of that outcome or its precision.

The analysis population is also important. The primary endpoint applies to eligible patients who completed neoadjuvant therapy and underwent protocol surgery with R0 or R1 resection, whereas the registry lists enrollment of 123. A result for the defined endpoint population would answer a narrower question than an outcome across all enrolled participants. The size of that endpoint population is not reported in the registry record.

The single-group design provides no separate control arm for a like-for-like comparison. This helps distinguish descriptive reporting from comparative evidence: a proportion observed in one group is not, by itself, an estimate of the difference that would occur under another treatment strategy. The registry's planning assumptions involving two arms are illustrations for hypothetical calculations, not a description of the trial's actual allocation.

Finally, safety counts and outcome definitions should not be treated as substitutes for missing efficacy results. The posted adverse-event information is descriptive, while the primary survival estimate and listed secondary outcome results are not reported. The record therefore demonstrates how design, analysis population, uncertainty, and outcome reporting each shape what can be concluded from a clinical trial entry.

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 primary limitation for interpretation is that the registry record does not report the primary endpoint estimate or its 95% confidence interval. The number evaluated for that endpoint is also not reported, despite the stated eligibility, treatment-completion, and surgery criteria defining the analysis population. The listed secondary outcomes likewise have no numerical results in the information available for this analysis.

The single-group design does not include a separate comparator arm, so it cannot provide a randomized comparison. The registry does not report the sample-size justification, detailed statistical plan, missing-data methods, or multiplicity procedures. It also lists 0 analyses, leaving no posted analysis methods or test results to evaluate.

The registry gives only partial details of the intervention schedule in the arm description; full postoperative regimen details are not reported in the registry record. It does not explain why the enrollment count of 123 differs from the safety record's at-risk count of 119. Those counts should not be used to infer participant flow or missing outcome data.

For safety, the record provides counts and selected event-term percentages but does not report further details about attribution, observation periods, or event-counting procedures. Without a comparator, these figures cannot show a relative safety difference. These limitations concern what can be learned from the registry information; they do not establish that unreported analyses or methods were or were not used outside the record.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Gemcitabine and Erlotinib Before and After Surgery in Treating Patients With Pancreatic Cancer That Can Be Removed by Surgery — NCT00733746.
• Registry record last updated 2019-10-21; status last verified 2019-10.
• Results first posted 2017-05-08.
• 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

NCT00733746 is a completed phase II, single-group study sponsored by the Alliance for Clinical Trials in Oncology. It enrolled 123 participants and studied gemcitabine and erlotinib before and after surgery for operable pancreatic adenocarcinoma. The primary endpoint was overall survival at two years, defined as the proportion alive at two years from registration among eligible patients who completed neoadjuvant therapy and underwent protocol surgery with R0 or R1 resection.

The primary estimate and 95% confidence interval are not reported in the registry record. The record lists 5 outcome measures and 0 analyses, alongside safety counts of 37 affected among 119 at risk for serious adverse events and 118 affected among 119 at risk for other adverse events. A separate comparator group is not listed.