Ixabepilone in Treating Patients With Recurrent or Persistent Endometrial Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ixabepilone in Treating Patients With Recurrent or Persistent Endometrial Cancer (NCT00095979), a na phase 2 study. The primary outcome is Frequency and Severity of Observed Adverse Effects Associated With Protocol Therapy (CTCAE Version 3).

2. Clinical Question

In practical terms, the safety question is descriptive: what adverse effects were recorded among eligible and treated patients during treatment and follow-up? The registry states that adverse effects were assessed every cycle until completion of study treatment and up to 30 days after treatment stopped. It gives an average data-collection period of 4 months. These details establish the stated observation window, but do not describe how often each patient was assessed beyond the cycle-based schedule or how missing observations were handled.

The registry records enrollment of 52. The safety results list 50 patients at risk for serious adverse events and 50 at risk for other adverse events. The registry record does not explain the difference between the enrollment figure and the safety denominators, so those figures should not be treated as interchangeable. Without a comparator, the observed adverse-effect counts describe the trial group; they cannot isolate effects attributable to ixabepilone from the underlying illness, other care, or other influences.

3. Trial Design

This was a phase II, single-group trial sponsored by the National Cancer Institute. It is recorded as completed. The registry lists a start date of 2005-05 and a primary completion date of 2009-07. Enrollment was 52. The study examined ixabepilone in patients with recurrent or persistent endometrial cancer, including conditions listed as endometrial adenocarcinoma, recurrent endometrial carcinoma, and stage IV endometrial carcinoma.

The treatment description specifies ixabepilone by intravenous infusion over 3 hours on day 1, with courses repeating every 21 days in the absence of disease progression or unacceptable toxicity. Masking is listed as none. Allocation is listed as not applicable, consistent with the single-group model. The record does not describe a parallel control group, random assignment, or blinded assessment. This design can describe observations among people receiving the study regimen, but it does not provide a direct within-trial comparison with another treatment.

The primary outcome is the frequency and severity of observed adverse effects associated with protocol therapy, assessed using CTCAE Version 3. Its stated population is eligible and treated patients. The outcome timeframe covers every cycle until completion of study treatment and extends up to 30 days after treatment stops; the registry gives an average data-collection length of 4 months. Progression-free survival and overall survival are listed as secondary outcomes. Numerical results for those secondary outcomes are not reported in the registry record.

Although the registry gives an enrollment figure, the safety outcome entries use 50 patients at risk for serious and other adverse events. The record does not explain how the enrolled population relates to these safety denominators. The registry also does not report a sample-size justification, a detailed statistical plan, interim analyses, or analysis methods for the outcomes. A completed status indicates the study’s registry status; it does not by itself supply missing outcome estimates or clarify how all enrolled patients contributed to each analysis.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Eligible and Treated Patients

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: Eligible and treated patients

6. Primary Endpoint

The registry lists the primary outcome as Frequency and Severity of Observed Adverse Effects Associated With Protocol Therapy (CTCAE Version 3), measured over Every cycle until completion of study treatment up to 30 days after stopping study treatment (average length of data collection = 4 months).

The primary endpoint concerns the frequency and severity of observed adverse effects associated with protocol therapy, using CTCAE Version 3. It is reported as a count of participants, so the basic unit is people with an event rather than the total number of event episodes. The stated population is eligible and treated patients. The observation period is every cycle through completion of study treatment, extending up to 30 days after stopping treatment; average data collection is described as 4 months.

Counting participants with an event is useful for describing how many people experienced an adverse effect during the specified observation period. It differs from counting repeated episodes: a participant with more than one occurrence may still contribute as a participant with an event, depending on the outcome definition. The registry record does not provide further detail about event-level counting, severity summaries, or how repeated events were handled.

Severity classification helps distinguish the seriousness of observed effects, while frequency conveys how commonly effects were recorded in the study group. Together, these features are relevant to describing the safety experience during treatment and follow-up. They do not establish whether an event was caused by ixabepilone. In a single-group study, interpretation must also account for the absence of a comparison group and the fact that participants had recurrent or persistent cancer.

The registry lists 25 participants affected by serious adverse events among 50 at risk, and 50 affected by other adverse events among 50 at risk. These are the counts recorded for those categories; the record does not provide a complete severity distribution for the primary endpoint or explain all details of outcome ascertainment.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count describe?

The primary outcome is expressed as a count of participants with an event. In general, a participant count answers how many people in the specified population experienced an outcome during the stated observation period. It is not necessarily a count of every event episode: repeated events in the same person may be represented differently depending on the outcome rules. The registry record does not explain how repeat events were treated for this outcome.

The posted safety results give counts and at-risk denominators for serious and other adverse events. Keeping numerator and denominator together is important: a count has meaning in relation to the population observed. Here, the listed denominators are 50 at risk for each category. Enrollment is recorded as 52, but the relationship between enrollment and the safety populations is not reported in the registry record. No adjustment or reconciliation should be inferred.

Why does the study design matter?

General statistical principle: a single-group study estimates what was observed in the group receiving the study regimen. A comparator group can help distinguish outcomes associated with the treatment strategy from outcomes that might also occur because of the illness, background care, or other factors. Without a comparator, a difference from an outside expectation would depend on assumptions not tested by this trial. The registry does not identify a control group or a comparative treatment effect.

Masking is listed as none. In general, masking can limit the influence of expectations on treatment delivery, outcome assessment, or reporting. Its absence does not show that any assessment was biased, but it is relevant when interpreting outcomes that may involve judgment. The record does not describe who assessed adverse events or whether any independent review was used.

How should severity and safety terms be read?

The primary endpoint refers to both frequency and severity of observed adverse effects and names CTCAE Version 3. In general, a toxicity grading system provides a structured way to classify event severity. The registry’s overall safety counts and the listed serious adverse-event terms are not a full severity distribution. No additional grading breakdown is reported in the registry record. The term-specific percentages should be quoted as recorded; the record does not clarify their detailed counting rules.

General statistical principle: safety event counts are descriptive unless a defined comparison and analysis support a comparative claim. A count can identify events recorded in a study population, but cannot by itself establish that the treatment caused them. Event duration, recurrence, timing relative to treatment, and attribution would add context; these details are not reported in the registry record.

What can uncertainty measures add?

General explanation: a confidence interval expresses the uncertainty around an estimate under a specified statistical model. It gives a range of values compatible with the observed data and assumptions; it is not a guarantee that the true value lies within that range. The registry record does not report confidence intervals for the adverse-event counts or term-specific percentages. It also does not report a model or inferential analysis for the primary outcome. Accordingly, the available safety figures can be described, but their precision cannot be assessed from the record with an interval estimate.

General explanation: over-dispersion matters when the observed variation in count data is greater than a model assumes. A model that fails to account for extra variation can give uncertainty estimates that are too narrow. Whether over-dispersion is relevant depends on the outcome definition and statistical model. Neither a count model nor an over-dispersion assessment is reported in the registry record, so it would be inappropriate to claim that either was used.

What does the planning illustration represent?

The planning assumptions describe a hypothetical two-arm illustration using equal allocation, a two-sided significance level of 0.05, and a normal approximation, with the target effect expressed as a stated fraction of an observed effect. This is distinct from the actual single-group trial design. It is a planning exercise, not an observed trial result and not evidence of the trial’s original design rationale. The registry record does not report the trial’s sample-size justification or the specific statistical plan used to analyze the outcomes. Any sample-size illustration should therefore be understood as hypothetical rather than as observed power or as a protocol feature.

The record lists no analysis records. It does not report the methods used to estimate progression-free survival or overall survival, how censoring was handled, which analysis populations were used for those outcomes, or whether adjusted analyses were planned. No specific inferential method can be attributed to the trial beyond the outcome descriptions and registry entries.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists a primary adverse-effect outcome and two secondary outcomes: progression-free survival and overall survival. It reports four outcome measures, but the available record does not provide a multiplicity strategy describing how conclusions across outcomes were to be controlled or prioritized. The record also has no analysis records. It is therefore not possible to determine whether the trial used a prespecified hierarchy, adjusted significance thresholds, or another approach to multiple outcome testing. No such procedure should be assumed.

The safety results report 50 at risk for serious adverse events and 50 at risk for other adverse events, while enrollment is listed as 52. The reason for this difference is not reported in the registry record. The record does not explain whether any enrolled patients were ineligible, untreated, excluded from a particular safety analysis, or missing outcome information. Those possibilities should not be inferred from the figures alone.

Missing-data handling is not reported in the registry record. There is no description of how incomplete adverse-event observations were treated, whether follow-up was complete for all participants, or how missing information affected the reported counts. The outcome timeframe includes assessment during each cycle and up to 30 days after treatment stopped, but this does not explain whether all participants had the same observation time.

The analysis populations for secondary outcomes are also not reported in the registry record. Details such as censoring rules for time-to-event outcomes, analysis dates, and statistical models are not included. These omissions limit reproducibility and make it difficult to assess how robust the reported safety summaries are to differences in follow-up or analysis decisions.

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 0% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: neutrophils (8.0%), nausea (6.0%), febrile neutropenia (4.0%), syncope (4.0%), pain: abdominal pain nos (4.0%).

The registry reports 25 participants affected by serious adverse events among 50 at risk, and 50 participants affected by other adverse events among 50 at risk. These counts refer to the safety categories as recorded; they do not describe the number of event episodes or establish that the treatment caused the events. The safety denominators are not the enrollment figure, and the registry record does not explain the relationship between them.

The listed serious adverse-event terms are Neutrophils, 8.0%; Nausea, 6.0%; Febrile Neutropenia, 4.0%; Syncope, 4.0%; Pain: Abdominal Pain Nos, 4.0%; and Thrombosis/Thrombus/Embolism, 4.0%. The record does not clarify whether these percentages count participants or events, or provide further details about overlap between terms. They should be interpreted as reported rather than translated into additional counts.

Deaths are not reported in the registry record. The listed serious terms do not constitute a complete account of all possible adverse effects or their severity distribution. The reported timeframe covers every cycle until completion of study treatment and up to 30 days after stopping treatment, with an average data-collection period of 4 months.

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

The registry record documents a completed phase II, single-group evaluation of ixabepilone in recurrent or persistent endometrial cancer. Its primary endpoint focuses on the frequency and severity of observed adverse effects, and the posted safety entries give participant counts for serious and other adverse-event categories. Those observations describe what was recorded in the safety population during the stated treatment and follow-up period.

The record does not establish that ixabepilone caused any particular event. Without a comparator, the observed events cannot be separated from those associated with the cancer, other care, or other circumstances. The figures also do not describe the full course, duration, or resolution of each event. The term-specific percentages are reported without detailed counting rules, limiting more granular interpretation.

The listed secondary outcomes are progression-free survival and overall survival, but their results are not reported in the registry record. The available safety information therefore does not answer whether the study regimen changed those outcomes. Nor does a completed study status alone indicate the magnitude or precision of an efficacy effect.

Enrollment is recorded as 52, whereas the safety entries list 50 at risk. Since the record does not explain that relationship, readers should retain the denominators attached to each safety result and avoid assuming that every enrolled patient contributed to every outcome. Confidence intervals, missing-data methods, and detailed analysis procedures are not reported in the registry record, so the precision and robustness of the summaries cannot be fully assessed.

The narrowest supported interpretation is descriptive: the registry records the stated adverse-event counts and terms among the listed safety population. Claims about comparative safety, causation, efficacy, or generalizability require information that the registry record does not report.

13. Why This Trial Matters Statistically

This trial illustrates why study design and endpoint definition should be considered alongside reported counts. The primary outcome is a participant count for observed adverse effects, and the registry gives explicit at-risk denominators for serious and other events. These details make the safety summaries more interpretable than counts presented without a population reference, while still leaving questions about the relationship between enrollment and the safety populations.

The single-group design also defines the scope of what can be learned. It supports description of the treatment group’s recorded experience, but provides no randomized comparator for estimating a relative difference. This matters especially for adverse events, which may occur for reasons beyond study treatment. A list of serious terms and percentages can signal what was recorded, but cannot independently establish attribution or comparative risk.

Outcome coverage is another statistical issue. The registry names progression-free survival and overall survival as secondary outcomes, yet their numerical results are not reported in the registry record. The difference between naming an outcome and reporting an estimate is consequential: without results and analysis details, readers cannot assess the evidence for those endpoints from this record.

Finally, the record’s missing details show why analysis transparency matters. The safety denominators do not match the enrollment figure, with no explanation; missing-data handling, uncertainty measures, multiplicity procedures, and detailed analysis methods are not reported. The appropriate statistical reading is therefore carefully bounded: preserve the reported counts and denominators, avoid causal or comparative claims, and recognize that important information needed to judge precision and reproducibility is absent.

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 direct limitation is the absence of a comparator arm. Because the study is single-group, its adverse-event findings are descriptive and cannot estimate a treatment-versus-control difference within the trial. Masking is listed as none, and the record does not describe who assessed events or whether independent review was used.

The registry lists enrollment of 52 but gives safety denominators of 50 at risk for both serious and other adverse events. The reason for the difference is not reported in the registry record. The record also does not describe the eligibility and treatment flow in enough detail to explain which participants contributed to each outcome or whether follow-up was complete.

The primary outcome is described as frequency and severity, but the posted entries do not provide a complete severity distribution or details on repeated events, event duration, attribution, or resolution. The listed serious adverse-event percentages have no further explanation of their denominator or counting rules. Deaths are not reported in the registry record.

Results for progression-free survival and overall survival are not reported in the registry record, despite their listing as secondary outcomes. Confidence intervals, statistical models, missing-data procedures, multiplicity handling, and the trial’s sample-size justification are also not reported. These gaps limit assessment of precision, analysis choices, and the robustness of conclusions. The registry’s completed status does not resolve those evidentiary limitations.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Ixabepilone in Treating Patients With Recurrent or Persistent Endometrial Cancer — NCT00095979.
• Registry record last updated 2019-07-24; status last verified 2019-07.
• Results first posted 2015-05-21.
• 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

NCT00095979 is a completed phase II, single-group trial sponsored by the National Cancer Institute. It studied ixabepilone in patients with recurrent or persistent endometrial cancer. The registry records enrollment of 52, a start date of 2005-05, and a primary completion date of 2009-07.

The primary outcome concerns the frequency and severity of observed adverse effects using CTCAE Version 3. The safety entries list 25 participants affected by serious adverse events among 50 at risk and 50 affected by other adverse events among 50 at risk. Serious-event terms and percentages are also listed. Progression-free survival and overall survival are named as secondary outcomes, but their results are not reported in the registry record.

The study has no comparator arm. The registry record does not explain the difference between enrollment and safety denominators, and does not report detailed analysis methods, missing-data handling, or uncertainty estimates.