Topotecan and Carboplatin in the First-Line Treatment of Patients With Extensive Stage Small Cell Lung Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Topotecan and Carboplatin in the First-Line Treatment of Patients With Extensive Stage Small Cell Lung Cancer (NCT00305942), a na phase 2 study. The primary outcome is Overall Response Rate (ORR), the Percentage of Patients Who Experience an Objective Benefit From Treatment.

2. Clinical Question

3. Trial Design

This was a phase II, single-group study sponsored by SCRI Development Innovations, LLC. The registry record lists the study as completed, with enrollment of 61. Its start is recorded as 2006-03 and primary completion as 2009-04. The design is identified as single group, with allocation NA and no masking. There is no randomized allocation to treatment groups and no concurrent comparator described.

The regimen combined topotecan and carboplatin. The arm description specifies topotecan 4mg/m2 IV on days 1, 8, and carboplatin AUC=5 IV day 1 only. Cycles were repeated every 21 days for > 4 cycles of both drugs, up to a maximum of 6 courses. Restaging studies were to be performed every 2 cycles (or 6 weeks.). These details describe the planned treatment schedule; the record does not say how many participants completed each course or whether treatment delivery varied.

The primary endpoint was overall response rate, assessed using RECIST v. 1 Criteria. The response category assigned was the best response obtained during treatment. The record also lists time to progression and overall survival as secondary outcomes, described as time in months from the first date of protocol treatment until worsening of disease or death, respectively. Numerical results for these secondary outcomes are not reported in the registry record.

The registry record does not report the protocol’s sample-size justification, prespecified statistical analysis plan, or interim analyses. The available design description supports interpretation as a single-arm study of regimen activity and safety, not as a controlled test of comparative effectiveness.

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

Analysis population for the primary outcome, as defined in the registry: All patients were included in the analysis.

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 Overall Response Rate (ORR), the Percentage of Patients Who Experience an Objective Benefit From Treatment, measured over 18 months.

Overall response rate is the percentage of participants who experienced an objective benefit, defined in the record as a complete or partial response according to RECIST v. 1 Criteria. A complete response required disappearance of all target lesions and disappearance of all nontarget lesions for at least 4 weeks. A partial response required at least a 30% decrease in the sum of the longest diameter of target lesions, using the baseline sum as the reference. The final response category represented the best response obtained during treatment.

Response rate is used in a phase II setting as a way to describe whether tumor measurements met predefined response criteria during treatment. It reduces complex changes in lesions to a participant-level category, which can be summarized as a proportion. It is not the same as a measure of how long a response lasts, how long participants live, or how outcomes compare with another treatment.

The registry record gives a timeframe of 18 months and states that all patients were included in the analysis. It does not report the number of complete or partial responses, the numerical overall response rate, or its 95% confidence interval. Consequently, the endpoint definition can be explained, but the observed response proportion and the precision of that estimate cannot be evaluated from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical details available in the registry record are limited. The study is identified as phase II and single group, with allocation NA and masking none. Enrollment was 61. The primary outcome was a percentage of participants with an event, specifically an objective response under RECIST v. 1 Criteria. The record states that all patients were included in the analysis and gives an 18-month timeframe. It does not report a numerical response estimate, its confidence interval, or analysis details beyond this description.

What does a response proportion represent?

As a general statistical concept, a response proportion summarizes the share of participants classified as having the defined outcome. Its interpretation depends on the response rules, the participant population included, and the period during which responses are assessed. In this trial, the registry defines response as complete or partial response and says the final assigned category was the best response obtained during treatment. A proportion would describe the observed fraction meeting those criteria in this study group; it would not, by itself, estimate a treatment effect relative to an unobserved control group.

The complete-response definition requires disappearance of all target lesions and disappearance of all nontarget lesions for at least 4 weeks. The partial-response definition requires at least a 30% decrease in the sum of the longest diameter of target lesions, taking the baseline sum as reference. These rules make the endpoint more specific than a general impression of improvement. The record does not describe how response assessments were adjudicated, whether assessors were independent, or how missing or unevaluable assessments were handled.

What would a confidence interval add?

As a general statistical concept, a confidence interval communicates uncertainty around an estimated quantity. For a response proportion, it would give a range of values compatible with the data under the interval’s statistical assumptions. A wider interval generally indicates less precision, while a narrower interval indicates greater precision. The registry record identifies a 95% Confidence Interval for the primary endpoint but does not report its bounds or the response estimate. It is therefore not possible to assess the estimate’s precision or reproduce its interval from the registry information.

A confidence interval does not remove design limitations. In a single-group trial, an interval around the observed response proportion can describe uncertainty about that group’s response rate, but it does not create a randomized comparison or account for differences from an external population. It also does not establish that treatment caused the observed responses.

How should the design shape interpretation?

As a general statistical concept, randomization helps balance measured and unmeasured prognostic factors across treatment groups on average. This study has one group and no randomized comparator, so it cannot use a between-group contrast to estimate the difference attributable to treatment. A one-group outcome can be useful as a descriptive signal, but comparisons with other studies may be affected by differences in participants, assessment, follow-up, and care.

The record lists time to progression and overall survival as secondary outcomes. Time-to-event methods are generally used when the outcome is the time until an event and participants may have different follow-up durations. Such methods can incorporate censoring, which occurs when an event time is not observed by the end of available follow-up. The registry record does not report numerical time-to-event results, censoring information, follow-up summaries, or the statistical methods used for those outcomes. No conclusions about their distributions or precision can be drawn.

The sample-size assumptions described for planning illustrations refer to 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. These are planning assumptions for hypothetical illustrations, not a description of this single-group trial’s design or observed power. The record does not report the trial’s own sample-size justification or target effect. Any planning calculation should not be interpreted as the number of participants actually enrolled for a particular power target.

What can the safety counts tell readers?

As a general statistical concept, counts and percentages describe how often events were recorded in the observed group. Their interpretation depends on the event definitions, observation period, and whether participants could contribute more than one event. The registry record reports numbers of participants affected for serious and other adverse events, but does not give event-level detail for every event or clarify all counting conventions. The term-specific percentages describe the record’s listed terms; they are not a substitute for a complete account of event severity, timing, duration, or attribution.

Over-dispersion is a general statistical issue that arises when observed variability exceeds what a model assumes. It can make standard errors too small if the model’s assumptions are not appropriate. The registry record does not describe a model for the primary binary endpoint, so there is no basis to claim that over-dispersion was present or that a particular adjustment was used. More broadly, the statistical analysis plan, handling of missing observations, and any interim analyses are not reported in the registry record.

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("Topotecan/Carboplatin")
n      <- c(61)
events <- c(35)
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  Topotecan/Carboplatin  61  35  57.4  44.1  70.0  44.9  69.0  44.8  69.0

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary endpoint, overall response rate, and two secondary outcomes, time to progression and overall survival. It does not report a prespecified strategy for controlling multiplicity across these outcomes or any other analyses. When several outcomes are tested, the chance of at least one apparently notable finding can increase; as a general statistical concept, multiplicity procedures may be used to manage that issue. Without a reported analysis plan, it is not possible to determine whether such procedures were planned or applied.

The record states that all patients were included in the analysis of the primary endpoint. It does not explain whether this means all enrolled participants were included in the denominator, how participants without an evaluable assessment were classified, or how missing response measurements were handled. The number of missing or unevaluable assessments is not reported in the registry record. The record also does not describe analysis populations for the secondary outcomes.

Missing data can affect an outcome estimate when participants without observed outcomes differ from those with observed outcomes. As a general concept, an analysis population and missing-data rule should be clearly defined so that readers can understand who contributed to an estimate and how incomplete follow-up was treated. Here, the statement that all patients were included is informative but does not answer those procedural questions.

The registry record does not report interim analyses, stopping rules, or a statistical analysis plan. Their absence from the record does not establish that they were absent from the study conduct; it means that they are not reported in the registry record. The primary endpoint’s numerical result and confidence interval are also not reported, limiting independent assessment of both the estimate and its uncertainty.

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: death not associated with ctcae term - disease progression nos (9.8%), hemoglobin (4.9%), platelets (4.9%), febrile neutropenia (3.3%), infection - other (pneumonia) (3.3%).

For the Topotecan/Carboplatin group, 61 participants were at risk for serious adverse events and 28 were affected. For other adverse events, 61 were at risk and 53 were affected. These are participant counts, not counts of all individual event occurrences. A participant may have experienced more than one event, but the record does not specify the counting convention in enough detail to determine how repeat events are represented.

The registry lists serious adverse event terms and associated percentages: Death not associated with CTCAE term - Disease Progression NOS, 9.8%; Hemoglobin, 4.9%; Platelets, 4.9%; Febrile Neutropenia, 3.3%; Infection - Other (Pneumonia), 3.3%; and Pancytopenia (NOS), 3.3%. These entries describe the terms and percentages recorded. They do not provide a complete clinical account of timing, duration, severity grading, or attribution for each participant.

The serious-event count and term-specific entries should be read as descriptive safety information from one study group. There is no control group for comparison, and the registry record does not report a separate causal assessment for each event. The number of deaths in the adverse-event group is not reported in the registry record. These limitations prevent comparative risk conclusions from these counts alone.

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

The record describes a phase II study of topotecan and carboplatin in first-line treatment for patients with extensive-stage small cell lung cancer. It identifies the treatment schedule, a primary response endpoint, secondary time-to-event outcomes, and adverse-event counts. Those details clarify what the study set out to measure and what aspects of the posted information can be interpreted.

The record does not report the numerical overall response rate or its 95% confidence interval. It therefore does not establish, from the information available, the proportion of participants who achieved complete or partial response or the precision of that proportion. The missing numerical estimate should not be interpreted as a zero response rate, and the endpoint definition alone cannot substitute for outcome results.

The study’s single-group design also sets a boundary on interpretation. Without a concurrent randomized comparator, the study cannot estimate a treatment difference against another regimen or separate treatment effects from other influences. A response observed in a single group would be descriptive rather than a controlled causal comparison. The record’s secondary outcome definitions do not supply numerical time-to-progression or overall-survival results.

The safety counts show that adverse events were recorded among participants in the treatment group, including serious events. They do not establish whether event rates were higher or lower than they would have been under another treatment, and the term list alone does not explain individual event courses or causality.

As a general statistical distinction, efficacy endpoints and safety summaries answer different questions: response criteria characterize tumor changes, while safety counts characterize recorded harms. Neither type of information, on its own, answers every question about duration, comparative benefit, or risk. The registry record supports a description of the study design and the outcomes it intended to assess, but not a definitive claim about comparative treatment effects or the size of the response result.

14. Why This Trial Matters Statistically

This trial is statistically notable for the clear distinction between an outcome definition and a reported outcome estimate. The registry record describes overall response rate in detail, including RECIST v. 1 Criteria and the best response during treatment, but does not report the numerical response rate or its confidence interval. A well-defined endpoint is necessary for interpretation; it is not sufficient to establish what the trial observed.

The single-group design also illustrates why a response proportion and a treatment effect are different quantities. A proportion describes outcomes in the treated group. A treatment effect requires a comparison, typically with a group representing an alternative condition. Here, the record identifies one group and allocation as NA, so a randomized contrast is not available. This matters when readers consider whether an observed outcome could be attributed to treatment rather than other factors.

The record lists secondary time-to-event outcomes alongside a binary primary endpoint. Those outcomes require distinct statistical summaries and assumptions. The registry gives definitions but no numerical results or analysis details for time to progression or overall survival. The existence of an endpoint listing should not be confused with a posted estimate or evidence about its precision.

Safety reporting offers another statistical lesson: counts of affected participants and term-specific percentages are descriptive, and their meaning depends on definitions and counting practices. Without a control group, comparative safety cannot be estimated from the listed counts alone. The registry also does not report the number of deaths in the adverse-event group.

Finally, the record does not report the trial’s own sample-size justification, statistical analysis plan, multiplicity approach, or missing-data procedures. These omissions matter because they limit assessment of how the study was planned and how results would be interpreted. Statistical transparency depends not only on numerical results, but also on the design and analysis details needed to evaluate them.

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 main limitation for interpreting efficacy is that the registry record does not report the primary endpoint’s numerical overall response rate or 95% confidence interval. Although the endpoint definition and timeframe are described, the estimate and its precision cannot be assessed. Numerical results for the listed secondary outcomes, time to progression and overall survival, are also not reported in the registry record.

The single-group design, with allocation listed as NA and masking as none, lacks a concurrent control group. It does not support a randomized comparison with another treatment. This limits conclusions about comparative effects and makes it difficult to distinguish treatment-related outcomes from other influences. The record does not give further details about eligibility criteria, baseline characteristics, or the representativeness of participants, limiting assessment of how widely results might apply.

Important analytic details are not reported in the registry record, including the statistical analysis plan, the sample-size justification, interim analyses, and the approach to multiplicity. Although the record says all patients were included in the primary analysis, it does not explain how missing or unevaluable response assessments were handled or define the denominator in more detail. It also does not describe the analysis populations or methods for secondary outcomes.

For safety, the registry gives counts of participants affected and a list of serious-event terms with percentages, but does not provide a full account of event timing, duration, severity, attribution, or counting conventions. The number of deaths in the adverse-event group is not reported in the registry record. These limitations constrain interpretation of both the efficacy and safety information.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Topotecan and Carboplatin in the First-Line Treatment of Patients With Extensive Stage Small Cell Lung Cancer — NCT00305942.
• Registry record last updated 2013-01-31; status last verified 2013-01.
• Results first posted 2013-01-24.
• 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

NCT00305942 is a completed phase II, single-group study sponsored by SCRI Development Innovations, LLC. It enrolled 61 participants and evaluated topotecan with carboplatin as first-line treatment for extensive-stage small cell lung cancer. The record lists a start of 2006-03 and primary completion of 2009-04.

The primary endpoint was overall response rate under RECIST v. 1 Criteria, with an 18-month timeframe. Time to progression and overall survival were listed as secondary outcomes. The record describes the regimen and reports serious and other adverse-event counts for the treatment group. It does not report the numerical response rate, its confidence interval, or numerical results for the secondary outcomes.

The single-group design does not provide a randomized comparator. The registry record also does not report the trial’s sample-size justification, statistical analysis plan, interim analyses, or missing-data procedures.