Study of Bevacizumab and Erlotinib in Patients With Advanced Non-small Cell Lung Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study of Bevacizumab and Erlotinib in Patients With Advanced Non-small Cell Lung Cancer (NCT00553800), a na phase 2 study. The primary outcome is Progression Free Survival (PFS).

2. Clinical Question

In statistical terms, the study was set up to describe time to progression or another event included in the progression-free survival definition among people receiving the combination. A single-group outcome can characterize what was observed in that group, but it cannot by itself separate treatment effects from other explanations, such as the course of disease or features of the enrolled participants. The record identifies the intended population and regimen, but gives no primary outcome estimate, analysis details, or participant-level description with which to assess how closely the enrolled group represents the intended population.

3. Trial Design

The registry describes a completed Phase II study sponsored by Fox Chase Cancer Center. Its official title identifies elderly patients with advanced non-small lung cancer, while the brief summary describes evaluation of bevacizumab and erlotinib in elderly patients with advanced non-small cell lung cancer. The condition is listed as carcinoma, non-small-cell lung.

The design is listed as single-group, with allocation marked not applicable and masking listed as none. These fields indicate that the registry does not describe randomized assignment between study arms or masking. The listed intervention group is Bevacizumab & Erlotinib, with bevacizumab 15 mg/kg intravenous every three weeks and erlotinib 150 mg by mouth every day. A separate comparator is not reported in the registry record. The study therefore does not support a direct randomized comparison of the combination with another treatment.

The registry lists enrollment as 32. The study started on 2007-07-05, reached primary completion on 2011-01-12, and is marked completed. These are registry entries about the study, not evidence that the primary outcome was successfully analyzed or reported. The outcome listing identifies one measure, median progression-free survival, with a 95% confidence interval and a timeframe of 3 years. However, the result itself is not reported in the registry record.

There are no analysis results reported in the registry record. The record also does not give a statistical analysis plan, details of analysis populations, or an account of how missing outcome observations were handled. The sample-size assumptions described for planning use a two-arm framework, equal allocation, a normal approximation, and a two-sided significance level of 0.05. Those are planning assumptions, not a description of the single-group study design. Sample-size illustrations based on assumptions should not be interpreted as observed power or as evidence about the study’s outcome.

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 Progression Free Survival (PFS), measured over 3 years.

The primary endpoint is median progression-free survival, measured in months. Progression-free survival is a time-to-event outcome: it describes time until progression or another event included in the endpoint definition. The registry defines progression using RECIST v1.0 criteria: a 20% increase in the sum of the longest diameter of target lesions, a measurable increase in a non-target lesion, or the appearance of new lesions. The registry does not further describe the event definition or state what other events, if any, were included.

A median is a summary of the time-to-event distribution. In general, it marks the point at which half of the observed event-time distribution lies on either side, subject to the way the analysis handles participants whose event time is not observed during follow-up. It is often used because it gives a readily interpretable description of the middle of a time-to-event distribution without assuming that the distribution is symmetric. The registry lists a 95% confidence interval to express uncertainty around the median estimate.

The stated timeframe is 3 years. That timeframe indicates the period associated with the outcome listing; it does not establish that every participant was observed for that duration. Follow-up details and the number of participants still at risk over time are not reported in the registry record. Most importantly, the record does not give the median estimate or its confidence interval. The endpoint’s definition and intended summary are available, but its observed result and precision cannot be evaluated from the registry information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

Time-to-event outcomes track the time until a defined event occurs. For this study, the named primary outcome is progression-free survival, and the registry gives a progression definition based on RECIST v1.0. The exact handling of other possible events is not reported in the registry record. The outcome is summarized as a median in months, with a 95% confidence interval, over a stated timeframe of 3 years.

What does a median time-to-event estimate describe?

In general, a median time-to-event estimate describes the middle of the event-time distribution. It is not an average, and it does not describe the experience of every participant. Some participants may have an event earlier or later than the median, while others may not have an observed event during the available follow-up. Those without an observed event are generally treated as censored in time-to-event methods: their available follow-up contributes information up to the point they are no longer observed, without asserting that the event occurred at that time. The registry record does not report how censoring was handled in this study or how many observations were censored.

What does a confidence interval contribute?

In general, a confidence interval expresses uncertainty around an estimate under the assumptions of the analysis method. A narrower interval indicates greater precision than a wider interval, while neither interval width nor the interval alone establishes causation. The registry lists a 95% confidence interval for the median but does not report its endpoints. Therefore, neither the estimated median nor its precision can be assessed from the registry record.

Why does the study design matter?

The registry lists a single-group model, no masking, and allocation as not applicable. These design details matter because a single group can describe outcomes among participants who received the listed regimen, but it does not create a concurrent randomized comparison. Without a comparator, an outcome cannot be interpreted as the difference between the combination and another treatment. Differences from other groups or studies could reflect differences in participant characteristics, follow-up, endpoint assessment, or other factors. The registry record does not provide a comparative analysis or a sponsor-reported hazard ratio.

What can adverse-event counts tell readers?

Adverse-event counts are descriptive summaries of events or participants recorded in specified categories. The record lists participants at risk and affected for serious and other adverse events, as well as deaths. These counts do not, by themselves, establish whether an event was caused by treatment, when it occurred, whether multiple events affected the same participant, or how long participants were followed for safety. The registry does not report those details. Serious-event terms and their listed percentages provide additional descriptions, but they do not amount to a comparison with an untreated or alternative-treatment group.

How should planning assumptions be understood?

Sample-size planning uses assumptions about the study design, statistical method, significance level, allocation, and effect a future study aims to detect. The assumptions listed for this record specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. They describe planning illustrations based on a fraction of an observed effect, with time-to-event planning expressed as a total number of events and other planning expressed as participants per arm. These assumptions do not match the registry’s single-group description, and the resulting sample-size estimates are not reported in the registry record. Planning illustrations are not observed power and do not show that a study had a particular chance of detecting an effect.

For a time-to-event analysis, the number and timing of events can affect the information available to estimate an outcome. General methods may account for censored observations and the timing of events, but the record does not describe the analysis method used. It also does not report an analysis population, an analysis plan, or procedures for missing data. No statistical model, adjustment strategy, or sensitivity analysis is reported in the registry record. Accordingly, statistical methods that would be relevant in principle should not be mistaken for methods confirmed to have been used in this study.

10. Multiplicity, Missing Data and Analysis Populations

Multiplicity concerns arise when a study evaluates several outcomes, comparisons, or analyses and then interprets selected results. The registry lists one outcome measure, median progression-free survival, and reports no analyses. It does not describe a broader testing strategy, an adjustment for multiple testing, or a prespecified hierarchy of outcomes. Because no analysis results are reported, the registry record does not permit assessment of how multiplicity was handled in practice. The absence of a reported adjustment is not evidence that a particular method was or was not used outside the registry record.

Missing data are important for time-to-event outcomes because participants may stop being observed before an event is recorded. Such observations can be censored, but the validity of an analysis depends on how follow-up and censoring are handled. The registry record does not report the amount or pattern of missing outcome information, loss to follow-up, censoring procedures, or sensitivity analyses. It is therefore not possible to determine whether missing observations could have influenced the primary estimate.

The record also does not identify analysis populations, such as which enrolled participants were included in the primary outcome analysis or how eligibility and follow-up were applied. Enrollment is listed as 32, but the registry does not report an analyzed population for progression-free survival. No analysis results are reported in the registry record. These omissions limit reproducibility and make it difficult to evaluate the relationship between enrollment, follow-up, and the intended endpoint. They should be treated as reporting gaps, not filled by assumptions about the protocol or analysis plan.

11. 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: dehydration (9.4%), pain (9.4%), confusion (6.2%), diarrhea (6.2%), shortness of breath (6.2%).

The registry reports safety information for the Bevacizumab & Erlotinib group. Serious adverse events are listed for 32 participants at risk, with 15 affected. Other adverse events are listed for 32 participants at risk, with 32 affected. The record also lists 17 deaths. These entries refer to separate categories as recorded; the information does not establish whether participants appear in more than one category or how events relate to one another.

The listed serious adverse-event terms are Dehydration and Pain, each at 9.4%; Confusion, Diarrhea, and Shortness of breath, each at 6.2%; and FTT at 3.1%. The record does not give further detail about event timing, severity grading beyond the serious-event classification, duration, treatment attribution, or the circumstances of death. The percentages are registry-listed descriptions, not comparative risk estimates. With no control group reported, these figures cannot show whether the recorded events were more or less frequent than they would have been under another treatment or condition. They are descriptive safety data, not proof of causation or a complete account of safety.

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

The registry record establishes that a completed, single-group Phase II study evaluated bevacizumab with erlotinib in elderly patients with advanced non-small cell lung cancer. It identifies the regimen, the intended population, and median progression-free survival as the primary outcome. It also lists selected adverse-event counts, serious-event terms, and deaths. Those details are useful for understanding what the study set out to examine and what safety information was entered into the registry.

The record does not report the primary outcome estimate or its 95% confidence interval. It also reports no analyses and no comparator group. As a result, the available information cannot characterize the observed median progression-free survival, its precision, or a treatment contrast. The listed safety information does not supply a comparison and does not establish that the regimen caused a particular event. The registry record does not provide enough detail to assess missing outcome information, follow-up, or the analysis population.

In general, evidence about an intervention depends not just on the outcome named in a study, but also on the results, design, analysis, and completeness of reporting. A single-group study can describe observed outcomes, but it cannot by itself isolate a treatment effect from other influences. Here, even the primary descriptive result is not reported in the registry record. Accordingly, the record supports a cautious account of the study’s design and recorded safety entries, not a conclusion about whether the combination improves outcomes or how it compares with another approach.

The distinction between a planned endpoint and a reported result is central. The endpoint description shows how progression was intended to be defined, while the missing estimate means the outcome cannot be interpreted quantitatively. Likewise, planning assumptions do not substitute for study results or indicate observed power. What the record does and does not report should therefore remain explicit when using the study to understand the evidence.

13. Why This Trial Matters Statistically

This trial illustrates why design labels and outcome reporting need to be read together. The registry identifies a Phase II study, but also classifies it as single-group with allocation not applicable. That design can describe experience among participants receiving the combination, but it does not provide a randomized control comparison. The distinction prevents a within-group outcome from being mistaken for a comparative treatment effect.

The endpoint is a time-to-event measure, for which both the estimate and its uncertainty matter. A median progression-free survival result would describe the observed distribution, while its confidence interval would indicate how precisely that median was estimated under the analysis method. Neither is reported in the registry record. This means that an important part of the planned statistical description is absent, even though the endpoint definition and intended timeframe are listed.

The record also demonstrates the limits of planning illustrations. The listed sample-size assumptions use a two-arm framework, while the study is classified as single-group. Such assumptions are useful only as planning context and are not observed power or evidence of an outcome. They cannot resolve the absence of a reported efficacy estimate.

Finally, safety counts require context. Counts and listed percentages describe entries in the registry but do not establish attribution, timing, or comparative risk. Taken together, these features make the record a useful example of why statistical interpretation depends on design, analysis, uncertainty, and transparent reporting, rather than on a study title or endpoint name alone.

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 most consequential limitation in the registry record is that it does not report the primary progression-free survival result. Neither the median nor its 95% confidence interval is available, despite the endpoint being identified as primary and having a stated timeframe of 3 years. The record also reports no analyses, so it offers no statistical estimate with which to assess the study outcome.

The single-group design is an additional limitation for comparative interpretation. The registry lists no randomized allocation and no separate comparator. Consequently, the record cannot support a like-for-like treatment comparison. This is a design feature, not a defect that can be corrected by interpreting the within-group safety counts as a control comparison.

Important details for evaluating a time-to-event analysis are not reported in the registry record. These include the analysis population, follow-up and censoring details, missing outcome information, and the statistical methods used. The record also does not give participant characteristics or further eligibility details, which limits assessment of the enrolled group and the applicability of any result.

Safety reporting is limited to the listed at-risk and affected counts, deaths, and selected serious-event terms with percentages. Timing, attribution, duration, and further event-level detail are not reported. The planning assumptions describe a two-arm illustration despite the single-group design, and the registry record does not report resulting planning estimates. These limitations constrain interpretation of both efficacy and safety and should not be filled by assumptions about the protocol.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Study of Bevacizumab and Erlotinib in Patients With Advanced Non-small Cell Lung Cancer — NCT00553800.
• Registry record last updated 2022-07-12; status last verified 2022-06.
• Results first posted 2022-07-12.
• 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 bevacizumab and erlotinib in elderly patients with advanced non-small cell lung cancer. Enrollment is listed as 32. The regimen was bevacizumab 15 mg/kg intravenously every three weeks and erlotinib 150 mg by mouth every day. The primary outcome was median progression-free survival in months, with a 95% confidence interval and a stated timeframe of 3 years.

The registry lists serious adverse events affecting 15 among 32 at risk, other adverse events affecting 32 among 32 at risk, and 17 deaths. It also lists selected serious-event terms and percentages. The primary outcome estimate and statistical analyses are not reported in the registry record. No comparator is listed, so the record does not provide a randomized treatment comparison.