This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Exemestane in Treating Postmenopausal Women With Stage IV Breast Cancer (NCT00810797), a na phase 2 study. The primary outcome is Progression-free Survival.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00810797 |
| Phase | Phase 2 |
| Condition | Breast Cancer |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 36 |
| Arms in the primary outcome | n/a |
| Lead sponsor | City of Hope Medical Center |
| Results posted | Yes |
2. Clinical Question
Population
Postmenopausal women with stage IV breast cancer were the intended population. The registry records 36 participants enrolled. It does not report further eligibility details or describe the characteristics of participants who entered the analysis of progression-free survival.
Intervention
Participants received oral exemestane once daily on days 1-14. Courses were scheduled to repeat every 21 days in the absence of disease progression or unacceptable toxicity. The registry also lists laboratory biomarker analysis, quality-of-life assessment, and immunohistochemistry staining.
Comparator
No comparison group is recorded. The trial is listed as single-group, with allocation recorded as NA and masking as none. Its results therefore do not provide a randomized, like-for-like comparison between exemestane and another treatment or a control condition.
Primary question
The primary endpoint was progression-free survival, measured in months and defined as a median with a 95% confidence interval. The question was how long participants remained alive without recorded disease progression during follow-up, which was described as extending up to 3 years. The registry record does not report the median or its confidence interval.
The trial also listed overall response rate as a secondary outcome. A response-rate result is not reported in the registry record. Consequently, the available record identifies the clinical questions and treatment schedule but does not give the numerical results needed to describe the observed progression-free survival or response rate.
3. Trial Design
This was a phase II, single-group trial sponsored by City of Hope Medical Center. The registry lists 36 participants enrolled and records the study as completed. The study began on 2008-12-17, and its primary completion date is listed as 2019-06-26. These registry dates describe the study record; they do not supply the duration of follow-up for each participant.
Participants received exemestane orally once daily on days 1-14, with courses repeating every 21 days if there was no disease progression or unacceptable toxicity. The record does not describe a concurrent control arm. Allocation is listed as NA, and masking is listed as none. Thus, the design is not a randomized comparison, and treatment outcomes cannot be interpreted as a direct estimate of the difference between exemestane and another assigned treatment.
The primary outcome was median progression-free survival, with a 95% confidence interval. Follow-up for this endpoint was specified as until disease progression or death from any cause, up to 3 years. Progression was defined using RECIST v1.0: 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.
Overall response rate was listed as a secondary outcome. The record also identifies laboratory biomarker analysis, quality-of-life assessment, and immunohistochemistry staining among the interventions or study activities. It does not report detailed measurement schedules, the analysis population, or how these additional assessments were incorporated into the statistical 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
| Stage | Treatment (Exemestane) |
|---|---|
| STARTED | 36 |
| COMPLETED | 36 |
| NOT COMPLETED | 0 |
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.
| Characteristic | Unit | Treatment (Exemestane) |
|---|---|---|
| Participants analysed | 36 | |
| Age, Continuous | years | 60 (42 to 79) |
| Sex: Female, Male: Female | Participants | 36 |
| Sex: Female, Male: Male | Participants | 0 |
| Race/Ethnicity, Customized: Caucasian | Participants | 13 |
| Race/Ethnicity, Customized: Hispanic | Participants | 15 |
| Race/Ethnicity, Customized: African American | Participants | 1 |
| Race/Ethnicity, Customized: Asian | Participants | 4 |
| Race/Ethnicity, Customized: Other | Participants | 3 |
| Region of Enrollment: United States | participants | 36 |
6. Primary Endpoint
The registry lists the primary outcome as Progression-free Survival, measured over Until disease progression of death from any cause, up to 3 years.
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | months |
| Endpoint classification | Time-to-Event Analysis |
Progression-free survival measures the time from a study-defined starting point until disease progression or death from any cause. In this trial, the registry specifies a Kaplan-Meier estimate and defines progression according to RECIST v1.0: 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. Follow-up was described as continuing until progression or death, up to 3 years.
The endpoint is useful in trials of advanced disease because it incorporates both radiographic or clinical progression and death, rather than counting only tumor responses at a particular assessment. A median expresses the time by which the estimated progression-free survival curve reaches its midpoint. The confidence interval describes uncertainty around that median; it is not a range containing every participant's time to progression or death.
The registry record names median progression-free survival and a 95% confidence interval as the primary result format, but reports neither numerical estimate. It also does not state the time origin used for the endpoint or provide details about assessment timing. Without the numerical estimate and its interval, the magnitude and precision of the endpoint cannot be assessed from the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The available information establishes the design and endpoint, but not the primary outcome value. Although progression-free survival was defined as a median in months with a 95% confidence interval, neither the median nor the interval is reported in the registry record. No numerical progression-free survival estimate should therefore be inferred from the enrollment count, follow-up limit, or study status.
The study is single-group, with no comparison arm listed. Any observed outcome in this design would describe participants treated in the study; by itself, it would not separate a treatment effect from other explanations for the observed course of disease. In particular, the record does not support a randomized treatment contrast. This is a design limitation, not evidence for or against a treatment effect.
The registry lists overall response rate as a secondary outcome, but does not report a numerical response result. It lists 2 outcome measures and 0 analyses. The record does not provide a p-value, hazard ratio, or other numerical estimate of an effect for the primary endpoint. It also gives no numerical information with which to assess the distribution of follow-up or the number of progression events used in the endpoint analysis.
The stated Kaplan-Meier product-limit method is appropriate as a general method for estimating time-to-event distributions when participants have different follow-up times and some observations are censored. The result depends on the event and censoring information collected. The registry does not report how many participants had progression, died without previously recorded progression, or were censored, nor does it describe censoring rules. These omissions make it impossible to evaluate the endpoint estimate's precision or its sensitivity to follow-up patterns from the registry record.
The posted adverse-event information records 4 participants affected by serious adverse events among 36 at risk and 35 affected by other adverse events among 36 at risk. The registry also lists five serious adverse-event terms, each with a frequency of 2.8%. These figures concern reported safety events and do not replace the missing progression-free survival result. The record alone does not establish whether any event was caused by treatment.
Overall, the registry supports a description of the intended population, regimen, design, and endpoint definition. It does not provide the numerical efficacy outcomes or analysis detail needed for a quantitative assessment of progression-free survival, response rate, or comparative benefit. A cautious interpretation should keep those missing results distinct from the study's completed status and its recorded enrollment.
9. Statistical Methods Explained
The primary endpoint is a time-to-event outcome. Rather than recording only whether progression occurred, time-to-event analysis uses both the event status and the time observed. A participant who has not had a recorded event by the end of available follow-up contributes information up to that point; this is generally described as censoring. The registry record does not report the number censored or the censoring rules used in this trial.
What does the Kaplan-Meier method estimate?
The registry says progression-free survival was estimated using the product-limit method of Kaplan and Meier. In general, this method estimates the probability of remaining event-free over time while accounting for participants whose event time is not observed during follow-up. It updates the estimated survival curve at event times and carries forward information from participants still under observation. The method does not require every participant to have an observed event, but interpretation relies on the quality of event and follow-up data and on assumptions about censoring.
Here, the event was defined as disease progression or death from any cause. Progression was specified 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 follow-up timeframe was listed as up to 3 years. The registry does not give the dates or schedule of tumor assessments, the time origin for calculating progression-free survival, or the number of observed events. Those details are not reported in the registry record.
What does a median and confidence interval convey?
A median time-to-event estimate is the point at which the estimated event-free probability reaches its midpoint. It is a summary of the estimated curve, not a claim that every participant experienced an event at that time. A 95% confidence interval communicates uncertainty in the estimated median under the method used. A wider interval generally indicates less precision, while a narrower interval generally indicates greater precision; the interval does not describe the spread of individual participant outcomes.
The registry specifies a median and 95% confidence interval as the intended reporting format, but does not include their values. As a result, the estimate's location and precision cannot be interpreted. The upper follow-up limit of 3 years is not itself a median estimate, and enrollment of 36 is not a substitute for the event information needed to estimate a time-to-event outcome.
Why does a single-group design matter?
A single-group study observes outcomes among participants receiving the study regimen without a concurrent control group recorded in the registry. In general, a treatment comparison requires a suitable contrast: observed outcomes under one condition compared with outcomes under another. Without that contrast, the study can describe the experience of its enrolled participants but cannot directly estimate a randomized between-group difference. The registry lists allocation as NA and masking as none, consistent with the absence of a recorded randomized comparison.
This distinction is important even if an outcome estimate is available. A time-to-event result from one group is not, on its own, an estimate of how outcomes would have differed under another treatment or no treatment. The registry does not report an external comparator or an adjusted comparison, and none should be assumed.
What can be inferred from the planning assumptions?
The record describes a planning illustration based on an observed effect, using a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. For time-to-event calculations, the stated quantity is the total number of events, using the Schoenfeld approach; other planning calculations are expressed as participants per arm. These are general planning assumptions, not observed trial outcomes or evidence that the single-group trial enrolled two arms.
The assumptions are not a report of the trial's original design justification. The registry record does not report the protocol's sample-size justification, and these planning assumptions should not be treated as the trial's own prespecified analysis plan. Nor do planning calculations constitute observed power. They illustrate sample-size requirements under stated hypothetical assumptions; they do not establish the probability that this completed study detected an effect.
The record says only sponsor-reported hazard ratios are used for time-to-event calculations, but it does not report a numerical hazard ratio for this trial. A hazard ratio is a relative comparison of event rates over time and ordinarily requires a comparison between groups. It is distinct from a median progression-free survival estimate. No such numerical comparison can be described from the registry information.
10. Multiplicity, Missing Data and Analysis Populations
The registry names progression-free survival as the primary outcome and overall response rate as a secondary outcome. It lists 2 outcome measures and 0 analyses. These entries identify the outcomes recorded in the registry, but do not describe a statistical analysis plan or establish which analyses were performed. The registry record does not report whether additional outcomes or subgroup analyses were planned.
Multiplicity arises when multiple outcomes, comparisons, time points, or subgroups are tested. In general, conducting many statistical tests can increase the chance of at least one apparently unusual result arising by chance. Researchers may address this through prespecified outcome hierarchies or statistical adjustments, but whether such approaches were used in this trial is not reported in the registry record. No adjustment method, testing hierarchy, or multiplicity strategy is stated.
The record does not provide the numerical result for the primary outcome or the secondary response-rate outcome. It also does not report p-values, confidence intervals for the response rate, or an analysis population. The number enrolled is recorded as 36, but the registry does not state how many participants were included in each outcome analysis or whether all enrolled participants were analyzed.
Details about missing observations are also not reported in the registry record. There is no description of missing outcome data, withdrawal handling, censoring rules, or whether any imputation was used. For a time-to-event endpoint, the amount and pattern of follow-up and the treatment of participants with incomplete observation affect interpretation. The registry information does not permit assessment of those issues.
These gaps do not prove that analyses or safeguards were absent; they mean that the record does not describe them. The statistical interpretation must therefore remain limited to the stated design, endpoint definitions, and safety counts, without attributing unreported procedures to the study.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Treatment (Exemestane) | 4 | 36 | 11.1% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Treatment (Exemestane) | 30 of 36 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment (Exemestane) | 35 of 36 |
Most frequent serious adverse event terms
| Event term | Organ system | Treatment (Exemestane) |
|---|---|---|
| Rectal hemorrhage | Gastrointestinal disorders | 1 of 36 |
| Disease progression | General disorders and administration site conditions | 1 of 36 |
| Device related infection | Infections and infestations | 1 of 36 |
| Skin infection | Infections and infestations | 1 of 36 |
| Hypotension | Vascular disorders | 1 of 36 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Treatment (Exemestane) |
|---|---|---|
| Hot flashes | Vascular disorders | 24 of 36 |
| Blood glucose increased | Metabolism and nutrition disorders | 22 of 36 |
| Aspartate aminotransferase increased | Investigations | 21 of 36 |
| Fatigue | General disorders and administration site conditions | 20 of 36 |
| Hemoglobin decreased | Blood and lymphatic system disorders | 18 of 36 |
| Joint pain | Musculoskeletal and connective tissue disorders | 16 of 36 |
| Pain | General disorders and administration site conditions | 14 of 36 |
| Constipation | Gastrointestinal disorders | 13 of 36 |
| Alkaline phosphatase increased | Investigations | 13 of 36 |
| Serum sodium decreased | Metabolism and nutrition disorders | 13 of 36 |
Serious events with the highest arm-level rate: rectal hemorrhage (2.8%), disease progression (2.8%), device related infection (2.8%), skin infection (2.8%), hypotension (2.8%).
For the treatment group, the registry records 36 participants at risk for serious adverse events and 4 affected. It records 36 at risk for other adverse events and 35 affected. These are participant counts associated with the registry's adverse-event categories; they are not a comparison between treatment arms, because no comparator arm is listed.
The registry lists Rectal hemorrhage, Disease progression, Device related infection, Skin infection, and Hypotension among the top serious adverse-event terms, each with a reported frequency of 2.8%. These term-specific entries should be read as recorded event frequencies, not as evidence that events were caused by exemestane. The registry does not report a causal assessment in the information available.
The record also lists 30 deaths. That count alone does not indicate how many deaths were attributed to disease progression, treatment, or another cause, nor does it supply timing or a comparison rate. The primary endpoint includes death from any cause as an event, but the registry does not provide the event breakdown or a numerical progression-free survival estimate.
Safety counts describe what was recorded in this group. Without a control group and fuller event details, they cannot establish comparative risk or explain the relationship between specific events and treatment.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a completed phase II, single-group study evaluated an intermittent exemestane regimen in postmenopausal women with stage IV breast cancer. It specifies oral dosing on days 1-14, with courses repeating every 21 days when there was no progression or unacceptable toxicity. It also defines progression-free survival and names overall response rate as a secondary outcome.
Those design details do not establish the size or direction of any clinical effect. The median progression-free survival and its 95% confidence interval are not reported in the registry record, and no numerical overall response rate is reported. It is therefore not possible to quantify the observed outcome, describe its precision, or judge how it compares with a particular alternative from this record.
The single-group design is central to interpretation. Even when outcomes are recorded, an uncontrolled study cannot provide a randomized comparison against another treatment. Differences between observed outcomes and outcomes under an alternative cannot be estimated directly from this design alone. The registry does not identify a comparator or report an adjusted treatment contrast.
The safety entries provide counts of participants with serious and other adverse events and list several serious-event terms. They do not by themselves establish that exemestane caused those events or define comparative safety. The death count is likewise not an attribution of cause.
Thus, the record supports a careful account of the trial's question, regimen, endpoint definition, and recorded safety figures. It does not support a numerical claim about efficacy, a causal conclusion, or a comparative treatment claim. The missing estimates and analysis details should be treated as unavailable, rather than inferred from study completion or enrollment.
13. Why This Trial Matters Statistically
This trial is statistically informative as an example of how design determines the questions a result can answer. A single-group study can characterize outcomes observed among participants receiving a regimen, while a randomized comparison is designed to contrast outcomes between assigned groups. The registry lists no comparator, so the distinction between describing an outcome and estimating a treatment contrast is especially important.
The primary endpoint is time-to-event, with progression-free survival estimated using the Kaplan-Meier product-limit method. This framework uses information from participants with different follow-up durations and can account for observations that end before an event is recorded. It also makes event definitions and censoring practices important. The record gives a RECIST v1.0 progression definition and a follow-up limit of up to 3 years, but does not report the event counts, censoring details, or endpoint estimate.
Reporting a median together with a confidence interval would communicate both the location and uncertainty of the primary estimate. Those numerical results are absent from the registry record. This is a reminder that a stated endpoint method does not substitute for its result: without the estimate and interval, precision and outcome magnitude cannot be judged.
The registry's safety counts also illustrate why descriptive counts should be kept separate from causal or comparative conclusions. Counts in a single group describe reported events in that group; without a comparator and further event attribution, they do not estimate excess risk due to treatment.
The statistical value of the record is therefore in clarifying the study design and the limits imposed by missing results. It identifies what was intended to be measured, while leaving the central numerical efficacy result unavailable for interpretation.
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 primary limitation for interpreting outcomes is that the registry record does not report the median progression-free survival or its 95% confidence interval. Although the endpoint and estimation method are specified, there is no numerical primary result to assess. The secondary outcome, overall response rate, is named but its numerical result is also not reported.
The design is single-group, with allocation recorded as NA and masking as none. No comparator is listed. As a result, the record does not provide a randomized treatment contrast. Any description of outcomes in this group would not, by itself, determine what would have happened under another treatment or control condition.
The registry records 36 participants enrolled, but does not state the analysis population or the number included in the primary endpoint analysis. It does not report event counts, follow-up distributions, censoring rules, assessment schedules, or the endpoint's time origin. These details are relevant to understanding how a Kaplan-Meier estimate was obtained and how precisely it reflects observed follow-up.
Other analysis details are also unavailable. The record does not report a statistical analysis plan, missing-data procedures, multiplicity handling, subgroup analyses, or a sample-size justification for the trial. Although planning assumptions are described, they should not be mistaken for the trial's original protocol or analysis plan.
The available adverse-event summary gives participant counts and selected serious-event terms, but not a detailed account of event timing, attribution, or comparative risk. The registry lists 30 deaths, without giving their causes or relationship to treatment. These omissions limit the conclusions that can be drawn from the safety record as well as from the efficacy outcomes.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Exemestane in Treating Postmenopausal Women With Stage IV Breast Cancer — NCT00810797.
- Registry record last updated 2026-10-29; status last verified 2026-10.
- Results first posted 2020-09-23.
- 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.
Continue through the Clinical Biostats statistical pathway
Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
This completed phase II study enrolled 36 postmenopausal women with stage IV breast cancer and evaluated a single-group, intermittent exemestane regimen. Participants received oral treatment once daily on days 1-14, with courses repeating every 21 days in the absence of disease progression or unacceptable toxicity.
The primary endpoint was median progression-free survival, estimated by the Kaplan-Meier product-limit method and defined using RECIST v1.0 progression criteria or death from any cause, with follow-up up to 3 years. Overall response rate was listed as a secondary outcome.
The registry record does not report the numerical primary or secondary efficacy results, the analysis population, or key follow-up and analysis details. It records 4 participants affected by serious adverse events, 35 affected by other adverse events, and 30 deaths. The single-group design does not provide a randomized comparator.