Enzastaurin in Treating Patients With Persistent or Recurrent Ovarian Epithelial Cancer or Primary Peritoneal Cancer: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Enzastaurin in Treating Patients With Persistent or Recurrent Ovarian Epithelial Cancer or Primary Peritoneal Cancer (NCT00407758), a na phase 2 study. The primary outcome is Number of Patients With Objective Tumor Response Rate (Complete Response [CR] or Partial Response [PR]) Using RECIST Version 1.0.

2. Clinical Question

The central statistical question is whether the registry’s posted results quantify objective responses in this single-group study. The response definition is detailed, but a definition is not a result. Without the observed response count and the corresponding analysis population, readers cannot assess the magnitude or precision of the primary endpoint from the registry record. Nor can a single-group outcome establish how the same participants would have fared under a different treatment or without enzastaurin.

3. Trial Design

This is a phase II study of enzastaurin hydrochloride in patients with persistent or recurrent epithelial ovarian cancer or primary peritoneal cancer. The registry lists the sponsor as the Gynecologic Oncology Group, an enrollment of 28, and a completed status. The recorded start is 2006-11, and primary completion is dated 2016-08-01. These registry dates describe the study record; they do not by themselves explain recruitment, follow-up, or the timing of individual assessments.

The design is recorded as single-group. Allocation is listed as not applicable, and masking as none. No concurrent control group is specified. Thus, results from this study describe the treated study group, and cannot provide a randomized comparison with another treatment. In an uncontrolled study, changes over time or outcomes observed after treatment cannot be separated from other explanations using a direct between-group contrast.

The registry identifies the primary population as eligible and treated patients, but does not report a more detailed definition of that analysis population, the number included in the primary endpoint analysis, or the handling of participants who did not complete assessments. Enrollment is listed as 28; that figure should not automatically be treated as the denominator for every outcome.

The primary outcome is objective tumor response, defined as complete response or partial response under RECIST version 1.0. Tumor assessments were scheduled by CT scan, or MRI if used to follow lesions for measurable disease, every other cycle for the first 6 months and every 6 months thereafter until progression for up to 5 years. Secondary outcomes listed include overall survival duration, progression-free survival duration, and prognostic factors. The registry lists 8 outcome measures and 0 analyses. Specific statistical methods, a sample-size justification, and interim analyses are not 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.

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 Number of Patients With Objective Tumor Response Rate (Complete Response [CR] or Partial Response [PR]) Using RECIST Version 1.0, measured over CT scan or MRI if used to follow lesions for measurable disease every other cycle for the first 6 months; every 6 months thereafter until disease progression for up to 5 years..

The primary endpoint counts eligible and treated participants who had an objective tumor response: a complete response or partial response according to RECIST version 1.0. It is a binary outcome at the participant level—each participant either meets the response definition or does not. Counting participants who meet a prespecified response definition offers a structured way to describe tumor response in a phase II study. It does not, by itself, establish a comparative treatment effect.

For complete response, RECIST 1.0 requires disappearance of all target and non-target lesions, no new lesions, and confirmation on two disease assessments at least 4 weeks apart. Partial response requires at least a 30% decrease in the sum of longest dimensions of all target measurable lesions, using the baseline sum as the reference, with no unequivocal progression of non-target lesions and no new lesions. It also requires confirmation on two disease assessments at least 4 weeks apart. If the only target lesion is a solitary pelvic mass assessed by physical examination and not radiographically measurable, the stated criterion is a 50% decrease in its longest dimension.

The assessment schedule specifies CT or, when used to follow measurable disease, MRI. The registry record describes how a response is defined and assessed, but does not report the number of participants who achieved complete or partial response. Without that result and its analysis denominator, the endpoint’s observed frequency and statistical precision cannot be evaluated from the record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a participant count measure?

The primary endpoint is a count of participants with an event, where the event is meeting the RECIST definition of complete or partial response. A count depends on both the number of participants meeting the definition and the population assessed. The registry identifies eligible and treated patients as the population, but does not report the response count or the number included in its primary analysis. An enrollment figure alone does not resolve either missing item.

For a binary endpoint, an analysis commonly expresses the count in relation to the number assessed, producing a response proportion. A confidence interval is a range that conveys the statistical uncertainty around an estimate under the assumptions of the method used. It does not represent a guarantee about the true value, and its width is affected by the amount of information in the data. No response proportion or confidence interval is reported in the registry record, so neither the observed frequency nor its precision can be assessed.

Why does the design affect interpretation?

In a randomized comparison, treatment groups can be compared according to their assigned interventions, with randomization supporting a causal interpretation under the trial’s assumptions. This record describes a single-group study and no randomized comparator. The primary result, if reported, would describe outcomes among participants receiving enzastaurin; it would not alone show what would have happened to those same participants under another treatment or no treatment.

The lack of masking is also part of the design. Masking can reduce some forms of influence on treatment delivery, participant reporting, or outcome assessment, depending on the study. The record lists masking as none. RECIST supplies explicit measurement and confirmation rules, but the registry does not state whether assessments were independently reviewed or whether any additional procedures were used to limit assessment bias.

How should the response definition be read?

RECIST version 1.0 separates complete response from partial response using lesion measurements and the presence or absence of new or progressing disease. Complete response requires disappearance of target and non-target lesions, no new lesions, and confirmation by two disease assessments at least 4 weeks apart. Partial response requires at least a 30% decrease in the sum of longest dimensions of target measurable lesions from baseline, no unequivocal progression of non-target lesions, and no new lesions; it too requires confirmation at least 4 weeks apart.

The registry describes a special case in which the only target lesion is a solitary pelvic mass measured by physical examination and not radiographically measurable. In that circumstance, the stated decrease required is 50% in the longest dimension. These rules define how the endpoint is classified; they do not tell readers how many participants were classified as responders. The described schedule uses CT or MRI if used to follow measurable disease, every other cycle for the first 6 months and every 6 months thereafter until progression for up to 5 years.

What can be inferred from the analysis information?

The registry lists 8 outcome measures and 0 analyses. This indicates that outcome measures are listed without analyses recorded in the registry entry. It does not establish that no analysis was conducted outside the registry; rather, the statistical analyses and their results are not reported in the registry record. The specific statistical plan, including any modeling choices, adjustment methods, confidence-interval method, or handling of repeated assessments, is not reported.

A sample-size justification is also not reported in the registry record. Any planning illustration should be understood as a hypothetical calculation under stated assumptions, not as a description of the original trial’s design justification or as observed power. Power is a design concept concerning the chance of detecting a specified effect under assumptions. It cannot be inferred retrospectively from the enrollment alone, and an observed result should be interpreted through its estimate and uncertainty rather than through observed power.

For binary outcomes, the amount of information depends on the number of participants with observed outcome status and the event frequency. Missing outcome status can alter both the available denominator and the interpretation of the result. The registry does not report missing-response handling, an imputation method, or a sensitivity analysis. It is therefore not possible to judge whether the primary result, if calculated elsewhere, included all eligible and treated patients or addressed missing assessments in a particular way.

Why does the absence of a comparator matter statistically?

A single-group study can describe the frequency of an outcome in its participants, but has no concurrent group against which to estimate a treatment contrast. A historical expectation or an external benchmark would require its own specification and assumptions; none is described in the registry record. It would be inappropriate to infer such a comparison from the phase designation or from the study rationale.

Likewise, a reported association between a prognostic factor and an outcome would not necessarily establish that the factor caused the outcome. The registry lists platinum sensitivity, initial performance status, and age at study entry among prognostic-factor outcomes, but the analyses and their results are not reported. Without methods, estimates, and uncertainty measures, no conclusion about those relationships is warranted.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, including the primary response outcome and secondary outcomes concerning overall survival, progression-free survival, and prognostic factors. It lists 0 analyses. The statistical plan for handling multiple outcomes or multiple tests is not reported in the registry record. When several outcomes or comparisons are examined, the chance of at least one apparently notable finding can increase; statistical methods may account for this, but no such method is described. The existence of several listed outcomes does not establish that all were analyzed or that any were statistically significant.

The primary population is described as eligible and treated patients. The record does not report the number included in the response analysis, the number with missing response assessments, the reasons for missingness, or how missing endpoint data were handled. It does not specify whether participants with incomplete follow-up were excluded, classified in another way, or included through an imputation or sensitivity analysis. These details matter because the response count and its denominator determine the endpoint estimate.

The registry also does not report a missing-data strategy for the listed time-to-event outcomes or prognostic-factor outcomes. Nor does it report a detailed definition of analysis populations for those outcomes. Enrollment of 28 should not be assumed to be the analysis denominator for every measure. Without the analysis populations and missing-data procedures, readers cannot assess how incomplete data may have affected the posted outcomes.

The outcome count and absence of registered analyses leave the multiplicity approach, missing-data handling, and analysis-population definitions unreported. These gaps limit interpretation of both the primary endpoint and the broader outcome set.

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: death no ctcae term - disease progression nos (11.1%), pain: abdominal pain nos (7.4%), obstruction, gi - rectum (3.7%), obstruction, gi - colon (3.7%), ascites (3.7%).

The registry safety entry lists the enzastaurin group with 27 participants at risk for serious adverse events and 12 affected. For other adverse events, it lists 27 at risk and 27 affected. These are separate safety summaries. The entry does not provide a serious-adverse-event death count; that value is not reported in the registry record.

The listed serious-event terms include “Death No Ctcae Term - Disease Progression Nos” at 11.1%, “Pain: Abdominal Pain Nos” at 7.4%, and “Obstruction, Gi - Rectum,” “Obstruction, Gi - Colon,” “Ascites,” and “Dehydration” at 3.7% each. These percentages are quoted as listed. They describe the registry’s event-term entries and should not be interpreted as a comparison with a control group.

Safety terms and counts do not, on their own, establish that the study drug caused an event. The registry entry does not report a causal assessment for each term, event timing, duration, or a full account of severity and resolution. Also, a participant-level count affected is not necessarily the same as a count of events, since a participant may experience more than one event. The safety figures are therefore descriptive and should be read within the limits of the information recorded.

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

The record establishes that this completed phase II study was designed to assess enzastaurin in persistent or recurrent epithelial ovarian cancer or primary peritoneal cancer. It specifies a single-group design, a primary response endpoint, RECIST version 1.0 criteria, an imaging schedule, and selected safety information. Those details clarify the intended question and how response was to be classified.

The record does not report the primary response count, the analyzed denominator, or an estimate with uncertainty. It therefore does not support a numerical statement about how frequently complete or partial response occurred in the eligible and treated population. It also does not report an analysis from which a comparative treatment effect could be estimated.

Even if a response count were available, a single-group result would describe the study participants rather than establish what would have happened under a different treatment. No comparator is recorded, and no randomized contrast is available. Findings from this design cannot by themselves distinguish an intervention effect from other influences on disease course or assessment.

The safety entry reports participants affected and selected serious-event terms, but it does not provide a comparative safety analysis or establish event causation. The registry does not report a death count in that entry. These figures should be understood as descriptive, with the recorded at-risk counts as context.

The completed status and enrollment figure do not remedy the missing primary outcome result. Nor do the listed secondary outcomes establish that analyses or estimates for those outcomes are available. The most defensible reading is that the registry documents the study design and outcome definitions, but does not contain enough primary-result information to quantify response or its precision.

13. Why This Trial Matters Statistically

This study illustrates an important distinction between a registered endpoint and a reported endpoint result. A protocol-style description can define a clinically relevant outcome in detail, including lesion measurement, confirmation, and assessment schedule, while still leaving the observed outcome count unavailable in the registry record. Statistical interpretation requires both a clear definition and the data needed to estimate the outcome.

It also shows why denominator information matters. The registry lists enrollment of 28, while identifying eligible and treated patients as the primary endpoint population. Without the number assessed and the number meeting response criteria, an endpoint frequency cannot be reconstructed. Treating enrollment as the outcome denominator would require an assumption not supported by the record.

The single-group design is another central statistical feature. It permits description of outcomes in the treated group, but does not supply a randomized estimate against a comparator. This distinction is especially important when interpreting language about how well a treatment performs: a within-group outcome and a comparative treatment effect answer different questions.

Finally, the registry lists multiple outcome measures but records 0 analyses. This highlights the value of transparent reporting of analysis populations, missing-data handling, multiplicity procedures, estimates, and uncertainty. Without those details, readers cannot determine the statistical strength or precision of findings across the outcome set. The record’s limits are not a reason to infer a result; they identify what remains unquantified.

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 principal limitation for statistical interpretation is that the registry record does not report the primary response count, its analyzed denominator, or a confidence interval. The outcome definition and assessment schedule are detailed, but the observed primary endpoint cannot be quantified from these entries. The enrollment of 28 does not establish the denominator for the eligible-and-treated analysis population.

The design is single-group, with allocation listed as not applicable and no masking. No control group is recorded, so a randomized comparative treatment effect cannot be estimated. Any outcome description from the treated group would also be open to explanations that a concurrent comparison could help assess.

The registry lists 8 outcome measures and 0 analyses. It does not report the statistical analysis plan, multiplicity procedures, missing-data methods, analysis-population definitions beyond eligible and treated patients for the primary outcome, or a sample-size justification. It also does not state whether response assessments underwent independent review. These omissions limit assessment of prespecification, bias, precision, and the robustness of any analyses reported outside the registry record.

The safety entry provides at-risk and affected counts plus selected event terms, but no comparative safety group, causal attribution for each event, or death count. The secondary outcomes are named, but their numerical results and analyses are not reported in the registry record. These limitations concern what can be concluded from the record; they do not establish that analyses or other information do not exist elsewhere.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Enzastaurin in Treating Patients With Persistent or Recurrent Ovarian Epithelial Cancer or Primary Peritoneal Cancer — NCT00407758.
• Registry record last updated 2019-03-20; status last verified 2019-03.
• Results first posted 2017-11-21.
• 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

NCT00407758 is a completed phase II, single-group study of enzastaurin hydrochloride in patients with persistent or recurrent epithelial ovarian cancer or primary peritoneal cancer. The registry lists the Gynecologic Oncology Group as sponsor, enrollment of 28, a recorded start of 2006-11, and primary completion on 2016-08-01. Masking is listed as none, and allocation as not applicable.

The primary outcome is the number of eligible and treated participants with complete or partial tumor response according to RECIST version 1.0. The registry describes response criteria and imaging follow-up, but does not report the primary response count or an analysis. It lists 8 outcome measures and 0 analyses. The safety entry reports 27 participants at risk and 12 affected for serious adverse events, and 27 at risk and 27 affected for other adverse events.

The study record supports description of its design, endpoint rules, and posted safety figures. It does not provide a numerical primary response estimate, an uncertainty interval, or a randomized comparison.