Treatment of Prostate Cancer With Adjuvant Bevacizumab Plus Erlotinib: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Treatment of Prostate Cancer With Adjuvant Bevacizumab Plus Erlotinib (NCT00203424), a na phase 2 study. The primary outcome is To Evaluate the Efficacy of Bevacizumab Plus Erlotinib.

2. Clinical Question

The registry also lists time to tumor progression and overall survival as secondary outcomes. These are distinct questions from the primary measure based on rising PSA. Their inclusion does not itself establish that numerical results or analysis details are available; those details are not reported in the registry record.

3. Trial Design

This was a completed phase II study of adjuvant bevacizumab and erlotinib in patients at high risk for early relapse following radical prostatectomy. The registry identifies the study as single-group and records masking as none. Allocation is listed as NA, and the record flags that this is not a randomized comparison. Accordingly, the design describes outcomes among participants receiving the combination, rather than a treatment contrast against a concurrent control group.

The intervention was erlotinib plus bevacizumab. Participants received erlotinib every day for 24 weeks and bevacizumab every 3 weeks for a total of 8 doses. The study is listed as completed. Its recorded start is 2006-01, and its primary completion is 2009-02. The registry lists Translational Oncology Research International as sponsor and prostate cancer as the condition.

The record gives enrollment as 23. For efficacy, 19 subjects were analysed; 4 were excluded because they withdrew before the first tumor assessment. That distinction matters: enrollment describes registration to treatment, while the efficacy population described in the record excludes those withdrawals. The efficacy analysis population should not be assumed to apply to the safety figures, which use a risk denominator of 22.

The registry lists a primary efficacy objective and secondary outcomes of time to tumor progression and overall survival. It records 4 outcome measures and 0 analysis entries. The protocol’s sample-size justification, detailed statistical plan, analysis timing and handling of any additional missing observations are not reported in the registry record. The study’s phase designation alone does not establish what inferential methods were planned or whether the trial was designed to provide a definitive comparative estimate.

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: There are no pre-assignment details to describe.

Treatment Period

Reasons for not completing this period:

Follow-up Period

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Of the 23 subjects registered for treatment, 19 were analysed for efficacy, 4 subjects were excluded from analysis because of withdrawal of subjects prior to first tumor assessment.

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 To Evaluate the Efficacy of Bevacizumab Plus Erlotinib, measured over Determined by time to tumor recurrence, as measured by rising prostate specific antigen (PSA) after radical prostatectomy..

The primary outcome is described as evaluating the efficacy of bevacizumab plus erlotinib. Its unit is participants, and its parameter is a number. The timeframe is tied to time to tumor recurrence, measured by rising prostate specific antigen (PSA) after radical prostatectomy. Thus, the registry frames the primary measure around the number of participants with the specified recurrence event, rather than reporting a treatment-versus-control difference.

PSA is used in the registry’s operational description as the marker for recurrence after surgery. In general, a defined event measure can make an outcome more reproducible by specifying what observation counts as an event. Interpretation still depends on the exact event definition, assessment schedule and analysis procedure; details beyond rising PSA after radical prostatectomy are not reported in the registry record.

The registry’s primary endpoint description also refers to time to tumor recurrence. In general, a time-to-event outcome can use both whether an event occurred and when it occurred, while a count of participants with an event records occurrence without necessarily conveying timing. The available description labels the measure as a number of participants, but does not provide numerical results or enough analysis detail to determine precisely how timing informed the reported primary analysis.

Time to tumor progression and overall survival are listed as secondary outcomes. Their numerical results, event definitions and analysis methods are not reported in the registry record. No conclusion about the primary outcome’s observed frequency, timing or uncertainty can be drawn from the endpoint description alone.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Statistical methods determine what an outcome estimate represents, how uncertainty is described and which comparisons are justified. For this study, the registry gives a single-group design and a participant-count description of the primary efficacy outcome. It does not report a detailed statistical analysis plan or numerical efficacy results. The concepts below explain how such methods are generally interpreted, without implying that a particular unreported method was used.

What does a single-group design estimate?

In general, a single-group study can describe the observed outcomes among people receiving the study intervention. It does not directly estimate a treatment contrast against a concurrent control group. A control group helps distinguish outcomes associated with treatment from outcomes that might also occur under another treatment or without the study intervention. Without that contrast, changes or events cannot be attributed to the intervention on the basis of the study design alone. Here, the registry identifies one treatment group and flags that the study is not a randomized comparison.

Randomization, when used, supports comparison by assigning participants to groups through a chance process. The registry records allocation as NA and does not describe a randomized allocation. The absence of masking is also recorded. In general, masking can reduce the influence of expectations on care, assessment or reporting; whether its absence affected this trial’s outcome assessment is not reported in the registry record.

How should a participant-count endpoint be read?

A count of participants with an event communicates how many people in the analysis population met the event definition. It is not, by itself, a time-to-event estimate, and it does not necessarily show when events occurred. The registry links recurrence to rising PSA after radical prostatectomy and describes the primary measure in terms of participants. It does not provide the numerical event count, more detailed event criteria, assessment schedule or statistical method used to handle time.

For a binary outcome, uncertainty is often conveyed using a confidence interval around an event proportion or a difference between groups. In general, a confidence interval represents a range of estimates compatible with the data under the method’s assumptions; a wider interval indicates less precision. A comparative interval requires a comparison estimate, and this study has no separate control group. The registry record does not report a confidence interval or an efficacy estimate, so precision cannot be evaluated.

Why do analysis populations matter?

The record distinguishes enrollment from the efficacy population: 23 subjects were registered, 19 were analysed for efficacy, and 4 were excluded because they withdrew before the first tumor assessment. The analysis population determines which participants contribute to a particular estimate. In general, exclusions can affect interpretation if people omitted from analysis differ in their outcomes or characteristics from those included. The stated reason for these exclusions is withdrawal before assessment; further details about their outcomes or reasons for withdrawal are not reported in the registry record.

Analysis populations can also differ by outcome. Safety summaries commonly use participants who received or were exposed to treatment, while efficacy summaries may use a defined analysis set. The safety entries list 22 at risk, whereas the efficacy population is given as 19. The record does not explain the relationship between these denominators, so they should not be assumed to identify the same participants or represent the same analysis set.

What role do secondary outcomes play?

Time to tumor progression and overall survival are listed as secondary outcomes. In general, time-to-event methods account for the time until an event and may also account for participants whose event has not been observed by the end of follow-up. Such methods rely on definitions of the event, follow-up and censoring. The registry record does not report numerical results, follow-up details or the analysis method for these secondary outcomes. It is therefore not possible to determine how those methods were applied.

Testing or estimating several outcomes raises a multiplicity question. In general, repeated significance tests can increase the chance of at least one apparently positive result when all underlying effects are absent. Researchers may address this through a prespecified hierarchy, adjustment or emphasis on estimation, but the appropriate approach depends on the protocol and objectives. The registry lists 4 outcome measures and 0 analysis entries; any multiplicity strategy is not reported in the registry record.

What do planning calculations mean?

Sample-size planning calculations ask how many participants might be needed under specified assumptions about an effect, variability, significance level, allocation and statistical method. They are prospective illustrations, not observed trial findings. The registry’s planning description specifies a two-sided significance level of 0.05, equal allocation between two arms and a normal approximation, with the effect framed as a stated fraction of the observed effect. It also states that this calculation is not the trial’s own design. For time-to-event planning, the description refers to a total number of events; other planning outputs are described as participants per arm. These assumptions do not turn the single-group study into a two-arm comparison, and do not establish the trial’s original enrollment rationale.

Over-dispersion is a general issue when count outcomes vary more than a simple model assumes. If present, a model that ignores it can understate uncertainty and make results appear more precise than warranted. The registry’s primary measure is a participant count, but no over-dispersion assessment or count model is reported. It would be inappropriate to infer that such a method was used or needed for this outcome from the brief endpoint description alone.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 4 outcome measures. It identifies efficacy as the primary objective and names time to tumor progression and overall survival as secondary outcomes. The remaining outcome-measure details and the order in which outcomes were to be assessed are not reported in the registry record. When several outcomes are examined, multiplicity matters because repeated testing can increase the chance of a nominally positive finding by chance. In general, a study may use prespecified testing order, adjustment or estimation-focused reporting to address this issue. The registry does not describe a multiplicity procedure.

The record lists 0 analysis entries and does not provide the numerical primary efficacy result or numerical results for the secondary outcomes. It also does not report confidence intervals, test statistics, model specifications or an analysis plan. Consequently, it is not possible to establish which inferential analyses were conducted or how any results were selected and interpreted.

For efficacy, 19 subjects were analysed, while 4 were excluded because of withdrawal before the first tumor assessment. The record does not report additional details about the withdrawals, missing assessments after entry into the efficacy population or methods for addressing missing data. In general, missing outcomes can affect an estimate when the probability of missingness is related to the outcome or to participant characteristics; sensitivity analyses can assess how assumptions about missing information influence conclusions. Whether such analyses were performed is not reported in the registry record.

The distinction between the efficacy analysis population and the safety denominator also matters. Safety figures use 22 at risk, and the efficacy description identifies 19 analysed subjects. The record does not explain the denominator difference. No assumptions about inclusion, exposure or missingness should be used to reconcile them.

11. Safety Results

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

Other (non-serious) adverse events

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

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: grade 3 hypertension related to bevacizumab (4.5%).

The registry reports safety figures for the Erlotinib + Bevacizumab group. The serious-adverse-event entry gives 22 at risk and 1 affected. The other-adverse-event entry gives 22 at risk and 22 affected. The adverse-event meaning is participants with an event, so these figures are participant counts for their respective categories. The record separately lists grade 3 hypertension related to bevacizumab as a top serious term, with 4.5% recorded.

These categories should be kept distinct: the serious-event count is not the same entry as the other-adverse-event count, and the listed term is a specific serious adverse-event term. The registry does not give further event-level detail, such as timing, duration, recurrence or individual outcomes. It also does not report a control group’s adverse-event figures. Therefore, the entries describe the reported safety experience in the treated group but do not establish a comparative risk attributable to the combination or to either drug separately.

The safety denominator is 22 at risk, while the efficacy population is described as 19. The registry does not explain the difference. These denominators should not be combined or substituted for one another. The listed 4.5% should be quoted as recorded rather than treated as a newly calculated estimate.

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

The record establishes that a completed phase II, single-group study evaluated adjuvant erlotinib plus bevacizumab after radical prostatectomy in patients described as being at high risk for early relapse. It specifies a daily erlotinib schedule for 24 weeks and bevacizumab every 3 weeks for a total of 8 doses. It also identifies rising PSA after radical prostatectomy as the basis for the primary recurrence measure and gives information about the efficacy population and selected adverse-event categories.

Those design and conduct details do not supply the primary efficacy result. The registry record does not report the numerical number of participants with recurrence, an estimate of time to recurrence, or a measure of uncertainty. It also does not report numerical results for time to tumor progression or overall survival. Thus, the available record does not show the size or precision of any efficacy finding. Missing numerical results should not be interpreted as evidence that an outcome occurred or did not occur.

The single-group design also limits what even a numerical outcome could establish. Without a separate control group, the study does not provide a randomized treatment contrast. In general, observed outcomes in treated participants may reflect the intervention and other influences, including the underlying disease course and care. The design therefore supports description of the treated group, not a definitive causal comparison with an alternative.

The safety information records 1 participant with a serious adverse event among 22 at risk and 22 participants with other adverse events among 22 at risk. Grade 3 hypertension related to bevacizumab is listed at 4.5%. These entries describe reported events, but they do not show comparative safety against another treatment or separate the contribution of bevacizumab from that of erlotinib.

The registry identifies 23 subjects registered for treatment, 19 analysed for efficacy and 4 excluded after withdrawing before the first tumor assessment. These population details are relevant to interpreting any efficacy estimate, but no numerical estimate is available to interpret. The protocol’s detailed analysis plan, multiplicity approach, sample-size rationale and additional missing-data methods are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically informative as an example of how design and reporting determine the scope of conclusions. Its phase II designation and stated objective describe the study’s purpose, but they do not replace a reported outcome estimate. To assess an efficacy result, readers need the observed outcome, an appropriate denominator and information about uncertainty. The registry describes the efficacy population but does not report the numerical primary result or its precision.

The single-group structure is central to interpretation. A treated-group outcome can describe what was observed among participants receiving the combination. A like-for-like control comparison is needed to estimate how those outcomes differ from an alternative under comparable conditions. The registry explicitly indicates that this is not a randomized comparison. As a result, the design does not isolate the treatment effect from other explanations for the observed course.

The record also illustrates why analysis populations and denominators should be read carefully. Enrollment is reported as 23, the efficacy population as 19, and safety figures use 22 at risk. The 4 efficacy exclusions are attributed to withdrawal before the first tumor assessment. These figures refer to different contexts, and the registry does not explain the denominator difference for safety. Treating them as if they were a common analysis set could misrepresent what each result covers.

Finally, multiple outcomes require clear reporting of which analyses were primary and how secondary findings were handled. The record names secondary outcomes and lists 4 outcome measures, but does not report an analysis plan or multiplicity strategy. Those omissions limit the ability to judge the strength and precision of any outcome claim. The record is therefore useful for understanding the intervention and broad design, while leaving the efficacy question quantitatively unresolved.

14. Limitations

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

The main trial-specific limitation is the absence of numerical efficacy results in the registry record. The primary outcome is described as a participant count tied to rising PSA after radical prostatectomy, but the record does not give the observed count, an estimate, a confidence interval or a test result. The listed secondary outcomes, time to tumor progression and overall survival, likewise have no numerical results or analysis details reported.

The single-group design has no like-for-like control comparison. Allocation is listed as NA, masking as none, and the record identifies the study as not randomized. This means that even an observed outcome would not, by itself, distinguish an effect of the combination from other influences on participants’ outcomes. The study also evaluates the combination, so the contribution of either drug separately cannot be isolated from this design.

The efficacy analysis excludes 4 subjects who withdrew before the first tumor assessment; the record says 19 were analysed for efficacy. It does not report further information about the withdrawals or any other missing data. Safety figures use 22 at risk, and the relationship between that denominator and the efficacy population is not explained. These differences constrain direct interpretation across efficacy and safety summaries.

Further limitations arise from missing methods information. The statistical plan, sample-size justification, multiplicity strategy, analysis timing, endpoint assessment details and methods for handling missing observations are not reported in the registry record. The record lists 4 outcome measures and 0 analysis entries, but does not describe which analyses were conducted. The stated sample-size calculations are planning illustrations rather than the trial’s own design. These gaps prevent assessment of the planned-versus-reported analysis and the precision that the study was intended to achieve.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Treatment of Prostate Cancer With Adjuvant Bevacizumab Plus Erlotinib — NCT00203424.
• Registry record last updated 2016-03-25; status last verified 2016-02.
• Results first posted 2011-05-09.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry describes a completed phase II, single-group study of adjuvant erlotinib plus bevacizumab for prostate cancer patients at high risk for early relapse after radical prostatectomy. Participants received erlotinib every day for 24 weeks and bevacizumab every 3 weeks for a total of 8 doses. The record lists 23 subjects registered for treatment; 19 were analysed for efficacy, with 4 excluded after withdrawal before the first tumor assessment.

The primary objective was to evaluate efficacy, with recurrence described in relation to rising PSA after radical prostatectomy. Time to tumor progression and overall survival are listed as secondary outcomes. Numerical efficacy results and detailed analysis methods are not reported in the registry record.

Safety entries give 22 at risk and 1 affected for serious adverse events, and 22 at risk and 22 affected for other adverse events. Grade 3 hypertension related to bevacizumab is listed at 4.5%. The study has no separate randomized comparator, limiting interpretation to the reported experience in the treated group rather than a controlled treatment comparison.