Carboplatin and Gemcitabine With Bevacizumab Every 2 Weeks for Stage IIIb/IV Non-small Cell Lung Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Carboplatin and Gemcitabine With Bevacizumab Every 2 Weeks for Stage IIIb/IV Non-small Cell Lung Cancer (NCT00400803), a non-randomized phase 2 study. The primary outcome is Time to Progression.

2. Clinical Question

3. Trial Design

This was a phase II, non-randomized, single-group study with no masking. The registry record lists 38 participants enrolled and identifies the condition as carcinoma, non-small-cell lung. Its official title describes first-line treatment for advanced, inoperable Stage IIIb/IV disease. A single-group design can describe outcomes among people receiving a regimen, but it cannot by itself provide a randomized estimate of how those outcomes differ from an alternative treatment or from no study treatment.

The intervention was a three-drug combination of gemcitabine, carboplatin, and bevacizumab, administered on a two-week cycle. The record gives doses and infusion durations for the drugs, but the regimen description ends before specifying how many cycles or how long treatment was intended to continue. That duration is not reported in the registry record. The study is marked completed, with a start date of 2007-03 and primary completion date of 2010-05.

The primary outcome is time to progression, with a timeframe from enrollment through 2 years. Its description defines the event as progression or death and says that subjects who do not progress are censored at their last tumor assessment. Four secondary outcomes are named: best overall response by cycle, duration of response, overall survival time, and time to best response. Numerical results for these outcomes are not reported in the registry record. No protocol, detailed statistical analysis plan, or explanation of the sample-size rationale is 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: Outcome data analysis is only available for 35 of 38 patients in database. Three patients are excluded: 1 never enrolled, 1 has no record of treatment and fup, 1 has no treatment fup.

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 Time to Progression, measured over From Enrollment Through 2 Years.

The primary endpoint is time to progression, measured in months. The registry describes it as the time from treatment start until the first documented sign of disease progression or death from any cause. A participant who does not progress is censored at the last tumor assessment. The stated timeframe is from enrollment through 2 years. The endpoint is recorded as a mean with a standard error, but the numerical estimate and its standard error are not reported in the registry record.

Time-to-progression measures when an event occurs rather than simply whether an event occurs. This can retain information about the timing of disease progression, while the censoring rule allows observations without a recorded event to contribute information up to their last tumor assessment. General statistical interpretation: censoring is informative only under assumptions about how the timing of follow-up relates to the chance of the event. The registry record does not describe how those assumptions were assessed.

The endpoint is used to address the study’s stated interest in disease progression and survival-related outcomes. Its definition includes death from any cause, but it is distinct from overall survival as a separately named secondary outcome. A reported estimate would need to be interpreted alongside its uncertainty, censoring, and the absence of a randomized comparator. Without the primary estimate, its standard error, or further analysis details, the registry record does not show the observed time to progression.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record identifies a continuous primary outcome reported as a mean with a standard error. It also describes an endpoint that involves event timing and censoring. These features matter when interpreting any reported estimate, but the record does not include the numerical estimate, its standard error, or a detailed statistical analysis plan.

What does the mean describe?

General statistical explanation: a mean is a measure of the central value of observations on a numeric scale. For an endpoint measured in months, it would summarize time on that scale. A mean can be sensitive to the distribution of observations, particularly when some values are much longer or shorter than most others. For time-to-event data, interpretation also depends on how censored observations are handled. The registry record does not describe the calculation used to obtain the listed mean.

A standard error describes the estimated precision of a statistic, rather than the spread of individual participant outcomes. General statistical explanation: a smaller standard error indicates greater precision for the estimated mean under the assumptions of the analysis. It is not a direct description of how varied participants’ times to progression were. Because no mean or standard error is reported, the precision of the primary result cannot be evaluated.

How should censoring be understood?

The endpoint description says that subjects who do not progress are censored at their last tumor assessment. Censoring means that the event time is not observed within the available follow-up; the record retains information up to the stated censoring point rather than treating that point as the event time. General statistical explanation: standard time-to-event methods rely on assumptions about the relationship between censoring and the event process. If people with different prospects of progression also have systematically different follow-up, estimates may be affected. The registry record does not report the number censored, follow-up patterns, or methods used to address censoring.

The endpoint description includes death from any cause as an event, while separately naming overall survival time as a secondary outcome. Those definitions should not be conflated. The registry record does not give additional detail about the distinction between the analyses or their results. It also does not report whether the mean was supplemented by another summary of event timing.

What does a confidence interval communicate?

General statistical explanation: a confidence interval expresses uncertainty around an estimate using a method with stated assumptions. It can show a range of values compatible with the data and analysis, rather than suggesting that the estimate is exact. The registry record does not report a confidence interval for the primary outcome. Without an estimate and uncertainty measure, readers cannot assess the range of plausible values from the posted results.

What can the design establish?

The allocation is non-randomized and the model is single group. General statistical explanation: a single-group result is descriptive of the observed group. A randomized concurrent comparison can help distinguish treatment effects from prognosis, selection, and other differences between groups; this study design does not include such a comparison. Therefore, even if an outcome estimate were reported, it would not alone provide a controlled treatment contrast.

The registry records no statistical analyses. No hypothesis test, adjusted estimate, analysis population for the primary endpoint, or handling of missing endpoint data is reported in the registry record. It is therefore not possible to tell whether the mean was estimated under a prespecified method, whether analyses accounted for prognostic factors, or whether assumptions were checked.

How should planning illustrations be read?

General statistical explanation: a sample-size calculation is a planning exercise, not an observed result and not evidence that a study had a particular probability of detecting an effect after it was completed. The stated illustration assumptions use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. For time-to-event calculations, the stated quantity is total events; other calculations are expressed as participants per arm for 80% power or another stated power target.

Those assumptions do not match the recorded single-group design as a like-for-like trial comparison: the study has no randomized two-arm allocation. The sample-size rationale used when designing the trial is not reported in the registry record. Any planning illustration should therefore be read as a hypothetical calculation under its stated assumptions, not as the study’s observed power, design rationale, or evidence of treatment benefit.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Intent To Treat - Lung Cancer Patients")
n   <- c(35)
m   <- c(3.1)
sp  <- c(0.4)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Intent To Treat - Lung Cancer Patients  35  3.100  2.366  2.287  3.913

11. Multiplicity, Missing Data and Analysis Populations

The registry record names one primary outcome and four secondary outcomes. The secondary outcomes are best overall response by cycle, duration of response, overall survival time, and time to best response. It does not report results for these outcomes, a hierarchy for testing them, or a procedure to adjust for multiple comparisons. A multiplicity adjustment is not reported in the registry record.

General statistical explanation: when several outcomes or repeated comparisons are examined, the chance of obtaining at least one apparently notable result by chance can increase. Prespecifying a primary endpoint and an analysis hierarchy can help clarify which findings are confirmatory and how secondary results should be interpreted. The registry lists the primary endpoint, but a detailed testing strategy and its rationale are not reported in the registry record. No statistical analyses are listed.

The endpoint description gives one specific rule for participants without progression: censoring at the last tumor assessment. It does not report the number of censored observations, the amount of missing assessment data, the number with a usable endpoint, or how other missing data were handled. The primary analysis population is not reported in the registry record. The adverse-event group is labeled intent to treat, but the record does not say whether that population definition applies to the efficacy outcomes.

General statistical explanation: missing outcome data can affect interpretation when the people without recorded outcomes differ from those with complete follow-up. A censoring rule addresses how some incomplete time-to-event observations are represented; it does not, by itself, explain the extent or reasons for missing data. Without participant flow, follow-up completeness, and analysis-population details, the impact of incomplete observations cannot be assessed from the registry record.

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 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: pulmonary embolism (10.5%), diarrhea (5.3%), dizziness (5.3%), headache (5.3%), hypertension (5.3%).

The registry record lists an intent-to-treat lung cancer group with 38 participants at risk for serious adverse events and 17 affected. For other adverse events, it lists 38 at risk and 34 affected. These are separate categories in the record; they should not be added together because the same participant may appear in both. The record does not explain whether participants could contribute multiple events or how event attribution was assessed.

The listed serious adverse-event terms and percentages are pulmonary embolism, 10.5%; diarrhea, 5.3%; dizziness, 5.3%; headache, 5.3%; hypertension, 5.3%; and ataxia, 2.6%. These percentages are registry entries, not a full description of the safety profile. The record does not report the corresponding event counts for each term, event timing, duration, severity grading, or treatment attribution.

Deaths are not reported in the registry record. The serious and other adverse-event figures describe recorded participant counts, not a comparison with another treatment group. Because the study is single group, these figures cannot establish how the observed events compare with an alternative regimen. They also do not indicate the primary efficacy outcome.

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

The record identifies a completed phase II study of gemcitabine, carboplatin, and bevacizumab for advanced, inoperable Stage IIIb/IV non-small cell lung cancer. It gives a treatment schedule, a primary endpoint definition, several secondary outcomes, and selected adverse-event figures. Those details help describe what the study set out to examine and what safety information was recorded.

The central result needed to interpret the primary question is absent: the registry record does not report the time-to-progression mean or standard error. It also does not report numerical results for the named secondary outcomes. The stated purpose refers to increased survival, but a purpose statement is not an outcome result. The record therefore does not establish how long participants remained free of progression, their overall survival, or their response outcomes.

The study’s single-group, non-randomized design also limits what an observed outcome could establish. General statistical explanation: without a concurrent randomized comparator, differences from another group or from expectations may reflect variation in participant characteristics, disease course, follow-up, or assessment, as well as treatment. The record does not offer a like-for-like control comparison.

The safety figures show that serious and other adverse events were recorded among participants in the study group. They do not provide a comparative risk estimate or full event-level detail. They should be read as descriptive registry figures, not as evidence that a particular event was caused by the regimen or as a complete assessment of safety.

In practical statistical terms, the registry record documents the study question and some design and safety information, but not the outcome estimates required to assess the primary endpoint. It cannot support a conclusion about treatment effect or a precise estimate of benefit. The absence of a reported endpoint result is a limitation of the available record, not evidence that no progression or survival outcomes occurred.

14. Why This Trial Matters Statistically

This trial is statistically informative as an example of how design and reporting constrain interpretation. It asks a clinically important question about a drug combination in advanced lung cancer, but its recorded design is a single treatment group without randomization or masking. Those features determine the kind of inference that can be made: the study can describe outcomes in its participants, but does not create a randomized contrast against another treatment.

The primary endpoint is defined in terms of time to progression, including death as an event and censoring participants without progression at their last tumor assessment. This makes clear that the endpoint is not simply a count of people who progressed. It also highlights why the analysis method, censoring information, and follow-up completeness matter. None of those additional analytic details or the numerical endpoint result is reported in the registry record.

The record also illustrates the difference between an outcome being named and an outcome being reported. Four secondary outcomes are listed, but their numerical results are absent. Likewise, a recorded adverse-event denominator and affected-participant counts provide useful descriptive information but do not replace a comparative safety analysis.

Finally, planning calculations are not the same as observed evidence. The stated sample-size illustration assumptions describe hypothetical calculations, including equal allocation between two arms, whereas the trial is recorded as a single-group study. The design rationale is not reported in the registry record. Keeping those distinctions clear helps prevent a planning quantity or an incomplete registry entry from being mistaken for a trial result.

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.

Several limitations specific to this record constrain interpretation. Although the trial is marked completed, no numerical result is reported for its primary endpoint, time to progression. The listed mean and standard error are not present, and the four secondary outcomes also lack numerical results. The record therefore does not permit assessment of the magnitude or precision of the outcomes the study intended to examine.

The design is non-randomized and single group, with no masking. There is no concurrent control group for a like-for-like comparison. The record does not report a protocol, statistical analysis plan, or sample-size rationale. Although planning assumptions are described for illustrations, they do not document the original design rationale and include equal allocation between two arms, unlike the recorded single-group model.

The treatment description specifies the drugs, doses, infusion times, and two-week cycle, but ends before stating the intended duration. That duration is not reported in the registry record. Eligibility criteria, participant characteristics, participant flow, and the number with evaluable primary-outcome data are also not reported in the registry record.

The censoring rule is stated, but the number censored, the amount and pattern of missing assessment data, follow-up completeness, and handling of other missing data are not reported. The primary analysis population is not specified. The safety group is labeled intent to treat, but the record does not establish the population used for efficacy analyses.

For safety, the record includes affected-participant totals and selected serious-event terms, but deaths, event-level counts, timing, severity grading, attribution, and recurrent-event handling are not reported in the registry record. Multiplicity procedures are also not reported. These limitations mean the available record supports a description of study features and selected safety reporting, but not a full appraisal of efficacy, precision, or comparative safety.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Carboplatin and Gemcitabine With Bevacizumab Every 2 Weeks for Stage IIIb/IV Non-small Cell Lung Cancer — NCT00400803.
• Registry record last updated 2017-12-28; status last verified 2017-12.
• Results first posted 2012-01-26.
• 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 NCT00400803, a completed phase II study of gemcitabine, carboplatin, and bevacizumab for advanced, inoperable Stage IIIb/IV non-small cell lung cancer. It lists 38 participants enrolled, a non-randomized single-group design, and no masking. The recorded start date is 2007-03 and the primary completion date is 2010-05.

The primary outcome is time to progression in months, defined from treatment start to progression or death, with censoring at the last tumor assessment for participants without progression. Its mean and standard error are not reported in the registry record. Four secondary outcomes are named, but their results are not reported. The safety group lists 17 participants affected by serious adverse events and 34 by other adverse events, with 38 at risk in each category. The record does not include a randomized comparison or a detailed statistical analysis plan.