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 Mepolizumab As a Steroid-sparing Treatment Option in the Churg Strauss Syndrome (NCT00527566), a na phase 1, phase 2 study. The primary outcome is Number of Participants With Indicated Side Effects.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00527566 |
| Phase | Phase 1, Phase 2 |
| Condition | Churg Strauss Syndrome |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Brigham and Women's Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The study concerns people with steroid-dependent Churg-Strauss Syndrome (CSS). The registry record lists Churg Strauss Syndrome as the condition and records an enrollment of 10. Further eligibility details and the characteristics of participants at baseline are not reported in the registry record.
Intervention
Participants received open-label mepolizumab, a monoclonal antibody against interleukin-5 according to the study summary. The stated purpose was to assess safety and tolerability and whether treatment would allow steroid tapering. Dose, administration schedule, and any treatment adjustments are not reported in the registry record.
Comparator
There was no listed comparison group: the design is single-group, allocation is recorded as NA, and the intervention is open-label. Consequently, the registry record does not provide a like-for-like control group for separating treatment-associated changes from other influences.
Primary question
The primary endpoint is the number of participants with indicated side effects. Its description focuses on side effects experienced 1 to 2 days after mepolizumab infusion, while the timeframe says participants were followed for approximately 44 weeks. The primary clinical question is therefore descriptive: what side effects were recorded among participants during the study, including those in the stated post-infusion window? The registry record does not report an inferential comparison or a formal estimate of treatment effect for this endpoint.
3. Trial Design
This was a completed Phase 1 and Phase 2 study sponsored by Brigham and Women's Hospital. The registry record gives a start date of 2007-09 and a primary completion date of 2009-08. Enrollment is recorded as 10, and the study condition is Churg Strauss Syndrome.
The design is single-group, with open-label mepolizumab and no listed comparator. Allocation is recorded as NA and masking as none. These features matter when interpreting outcomes: measurements were collected in a treatment group without a concurrent control group, and treatment was not masked. Any changes observed during follow-up therefore cannot, from this design alone, be attributed to mepolizumab rather than to other influences or the natural course of participants' condition.
The study summary describes the intended purpose as assessing whether mepolizumab is safe and well tolerated and whether it allows steroid tapering in people with steroid-dependent CSS. The intervention is identified as mepolizumab, a monoclonal antibody against interleukin-5. Dose, route, administration schedule, permitted background treatment, and the detailed tapering procedure are not reported in the registry record.
Participants were followed for the duration of the study, approximately 44 weeks, according to the primary endpoint timeframe. The primary outcome is the number of participants with indicated side effects, described as effects experienced 1 to 2 days after infusion. The record also names secondary outcomes concerning steroid dosing, overall positive change in CSS via measures outlined in study aims, and exacerbation rate. Although the record lists 5 outcome measures, it records 0 analyses. Results for those secondary outcomes and the statistical analysis plan 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
| Stage | Mepolizumab |
|---|---|
| STARTED | 10 |
| COMPLETED | 10 |
| 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 | Mepolizumab |
|---|---|---|
| Participants analysed | 10 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 10 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 48 (SD 5) |
| Sex: Female, Male: Female | Participants | 8 |
| Sex: Female, Male: Male | Participants | 2 |
| Race/Ethnicity, Customized: Participants – # White Participants | Participants | 7 |
| Race/Ethnicity, Customized: Participants – Unknown | Participants | 3 |
| Region of Enrollment: United States | participants | 10 |
6. Primary Endpoint
The registry lists the primary outcome as Number of Participants With Indicated Side Effects, measured over Participants were followed for the duration of the study, approximately 44 weeks.
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint is the number of participants with indicated side effects. The registry description specifies side effects experienced 1 to 2 days after mepolizumab infusion. The stated follow-up period is approximately 44 weeks. The endpoint is a participant count rather than a continuous measurement: it records whether participants were reported as experiencing an indicated side effect, not the severity or duration of every symptom.
Counting participants with events is a direct way to describe how often a safety outcome was observed in a small treatment group. It can help readers distinguish the number affected from the total number at risk. However, the endpoint label alone does not clarify how side effects were selected as “indicated,” how they were elicited, whether events were assessed after every infusion, or how multiple events in one participant were handled. Those details are not reported in the registry record.
The posted safety counts include one participant with a serious adverse event and nine participants with other adverse events, each among 10 at risk. These are descriptive safety counts, not a comparative estimate of risk. They do not establish that mepolizumab caused an event. The registry record does not report an inferential analysis for the primary endpoint, nor does it provide a confidence interval or a comparison against an untreated or alternative-treatment group.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The posted data describe a small, single-group experience with open-label mepolizumab. The safety denominators are 10 participants at risk. One participant is recorded as having a serious adverse event, and nine are recorded as having other adverse events. The record identifies Fractured Hip as the top serious adverse event term, with 10.0% shown. These entries describe what was recorded; they are not evidence by themselves that the intervention caused an event.
The serious and other adverse-event counts are separate registry categories. They should not be added to make a total number of participants with any adverse event, because the record does not say whether the categories overlap or how participants with multiple events were counted. The serious-event term is reported separately from the count of participants with a serious event; the record does not give further clinical details about the fracture or its relationship to treatment. Deaths are not reported in the registry record.
The absence of a comparator places a firm limit on interpretation. A single-group count can describe events among treated participants, but it cannot show how many events would have occurred without mepolizumab or under another treatment. Open-label conduct can also influence how events are noticed, reported, and classified. The registry record does not describe event-adjudication procedures, blinding of safety assessors, or rules for assigning causality.
The primary endpoint description focuses on events experienced 1 to 2 days after infusion, while the stated follow-up is approximately 44 weeks. The registry record does not clarify how the specified window relates to collection of the broader safety counts. No estimate of uncertainty, hypothesis test, or adjusted analysis is reported for the endpoint. Thus, the counts should be read as descriptive registry results rather than as precise estimates of an underlying event rate or as evidence from a controlled comparison.
The study summary also identifies steroid tapering as an aim, and secondary outcomes include steroid dosing and exacerbation rate. Those aims do not substitute for results: findings for them are not reported in the registry record. The record lists 5 outcome measures but records 0 analyses, so it does not provide an analysis framework with which to assess those outcomes or evaluate their statistical precision.
Any sample-size calculations associated with the posted material are planning illustrations based on an observed effect and specified assumptions, not the trial's design justification or evidence of observed power. The record does not report the original sample-size justification. Such illustrations cannot remedy the absence of a control group, an analysis, or uncertainty estimates for the reported counts.
9. Statistical Methods Explained
Interpreting a small clinical study starts with its design and the type of outcome being counted. This study has a single treatment group, open-label masking, and no listed allocation to alternative groups. The primary endpoint is a participant count. These details determine which statistical questions can be answered: the record can describe observed safety events in the treated group, but it cannot estimate a randomized between-group contrast.
What does a participant count represent?
A participant count indicates how many people in a defined group were recorded as experiencing an outcome. Its meaning depends on a clear numerator, a corresponding denominator, and a consistent rule for deciding what qualifies as an event. Here, the adverse-event entries report one participant with a serious event and nine with other adverse events, each among 10 at risk. These are descriptions of participants, not necessarily counts of all event episodes. A person may experience more than one event, and the registry record does not explain whether the categories overlap or whether recurring events were counted separately.
The primary endpoint wording refers to the number of participants with indicated side effects, while its description specifies side effects experienced 1 to 2 days after infusion. The record does not clarify the event collection procedures, the definition of an indicated side effect, or how the post-infusion window was applied. Definitions and collection schedules matter because different rules can yield different counts even when the underlying experience is similar.
Why does the single-group design matter?
A controlled comparison estimates how outcomes differ between groups that receive different assigned interventions. In a randomized study, allocation can help balance measured and unmeasured factors on average, though it does not guarantee perfect balance. This study does not report such a comparison: it is single-group, with allocation recorded as NA. There is therefore no concurrent control estimate for background event frequency or for changes that might occur without the study intervention.
Without a comparator, temporal changes and adverse events cannot be attributed to treatment using the study design alone. The open-label conduct is also relevant because participants and study staff know the intervention being given. Knowledge of treatment can influence reporting, assessment, and classification. The registry record does not report blinded outcome assessment or independent event adjudication.
What would uncertainty estimates add?
A confidence interval is a statistical range intended to express uncertainty around an estimate under a specified method and assumptions. For a participant count expressed relative to the number at risk, an interval can show how imprecisely the observed data estimate a broader event frequency. In a small group, the range may be wide because only a limited amount of information is available. A confidence interval would still describe sampling uncertainty, not correct for a missing comparator, incomplete outcome definitions, or possible measurement bias.
The registry record does not report confidence intervals, p-values, or an inferential analysis for the primary endpoint. It records 0 analyses. The posted counts should consequently be treated as descriptive, and readers should not infer statistical significance or precision from the counts alone. The serious-event count and other-event count should not be combined unless the event definitions and overlap rules are known.
How should planning calculations be understood?
Sample-size calculations based on an observed effect can illustrate how a future comparison might be planned under stated assumptions. The planning assumptions described for the associated material include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect specified as a fraction of the observed effect. These calculations are planning illustrations, not the design used in this single-group study. They do not show that the study had a particular probability of detecting an effect, and they are not observed power.
The original sample-size justification is not reported in the registry record. It is also not reported whether the observed effect used for planning came from a prespecified endpoint or how it was estimated. An illustrative calculation cannot be treated as a retrospective validation of the study's enrollment or as a substitute for a controlled design.
What analysis details remain unknown?
The record does not report the statistical methods used for the primary endpoint, an analysis population, handling of missing observations, or whether any participants were excluded from analyses. It does not describe multiplicity control, interim analyses, or a prespecified hierarchy among outcomes. These omissions limit assessment of how the reported results were generated and whether all planned analyses are represented. General statistical principles can explain why those details matter, but the record does not support conclusions about which procedures were actually used.
10. Multiplicity, Missing Data and Analysis Populations
The registry record lists 5 outcome measures and names secondary outcomes concerning steroid dosing during the trial, overall positive change in Churg-Strauss Syndrome via measures outlined in study aims, and exacerbation rate. It records 0 analyses. The specific outcome definitions, analysis hierarchy, and prespecified approach to multiplicity are not reported in the registry record.
Multiplicity arises when several outcomes or statistical tests are considered. Without a stated plan, it is difficult to know whether the primary endpoint was treated as the sole confirmatory outcome, how secondary outcomes were interpreted, or whether any adjustment for multiple testing was intended. The available record does not establish that a particular adjustment was or was not performed; the method is not reported in the registry record.
Missing-data methods and analysis populations are also not reported in the registry record. The safety entries give 10 participants at risk for each listed adverse-event category, but they do not describe attendance, follow-up completeness, withdrawals, or the handling of unavailable observations for other outcomes. A stated denominator does not by itself establish complete follow-up for every endpoint.
The record does not report interim analyses or stopping rules. Their presence or absence cannot be inferred from the completed status. These gaps matter because analysis choices can influence which participants contribute to results and how uncertainty is assessed. Without those details or reported analyses, interpretation should remain descriptive and confined to the counts and study features that are recorded.
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 |
|---|---|---|---|
| Mepolizumab | 1 | 10 | 10.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Mepolizumab | 9 of 10 |
Most frequent serious adverse event terms
| Event term | Organ system | Mepolizumab |
|---|---|---|
| Fractured Hip | Musculoskeletal and connective tissue disorders | 1 of 10 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Mepolizumab |
|---|---|---|
| Upper Respiratory Infection | Respiratory, thoracic and mediastinal disorders | 7 of 10 |
| Wheezing and Shortness of Breath | Respiratory, thoracic and mediastinal disorders | 7 of 10 |
| Headache | Nervous system disorders | 4 of 10 |
| Digestive System Issues | Gastrointestinal disorders | 3 of 10 |
| Churg-Strauss Syndrome Flair | Endocrine disorders | 3 of 10 |
| Sinusitis | Respiratory, thoracic and mediastinal disorders | 3 of 10 |
Serious events with the highest arm-level rate: fractured hip (10.0%).
The registry reports one participant with a serious adverse event among 10 at risk and nine participants with other adverse events among 10 at risk. Fractured Hip is listed as the top serious adverse event term, with 10.0%. These are safety descriptions from the treated group, not a comparison with another treatment or with no treatment.
The serious and other categories should be read separately. The record does not state whether a participant with a serious event could also appear among those with other adverse events, so the counts should not be combined. It also does not provide event-level details, timing beyond the primary endpoint description, severity grading, or a causal assessment. The listed serious-event term does not establish that the event was caused by mepolizumab.
The registry record does not report deaths. That wording reflects the information recorded, not confirmation that no deaths occurred. Because the study is single-group and includes 10 participants at risk, the counts offer a limited descriptive account and cannot establish comparative safety or precisely characterize uncommon events.
12. What the Result Does, and Does Not, Mean
The registry record establishes that this completed, open-label, single-group study evaluated mepolizumab in the context of steroid-dependent Churg-Strauss Syndrome. It records an enrollment of 10 and describes follow-up of approximately 44 weeks for the primary endpoint. It also reports one participant with a serious adverse event and nine with other adverse events, each among 10 at risk, and names Fractured Hip as the top serious adverse event term at 10.0%.
These observations describe the safety information recorded for this group. They do not establish that mepolizumab caused any specific event, nor do they show how event frequency compares with another treatment or with no treatment. A single-group design without masking leaves no concurrent control for separating treatment effects from other explanations. The record also does not provide enough detail to assess event attribution or the full rules for identifying and counting side effects.
The study's stated aim included whether treatment would allow steroid tapering, and the registry lists steroid dosing and exacerbation rate among secondary outcomes. Those aims should not be confused with demonstrated results. Findings for these outcomes, and an inferential analysis of the primary endpoint, are not reported in the registry record. The record's outcome titles describe questions of interest, not conclusions about what happened.
Statistical precision is also not established by the posted counts. No confidence interval or p-value is reported for the primary endpoint. Planning calculations based on an observed effect, if consulted alongside these results, are illustrations for future design under assumptions; they are not evidence that this study had adequate power or that a treatment effect was established. The appropriate interpretation is therefore narrow: the registry records these participant counts in a small, uncontrolled study, while comparative effects and broader conclusions remain unresolved by the reported analyses.
13. Why This Trial Matters Statistically
This study is a useful example of why design and analysis must be read together. A safety count may be clinically relevant as a description of what was observed, but the same count has a different meaning when there is no concurrent control group. The single-group, open-label design supports a descriptive account of participants receiving mepolizumab; it does not provide a like-for-like comparison that isolates the intervention's effect.
The registry's endpoint wording also illustrates the importance of operational definitions. The primary outcome is a count of participants with indicated side effects, and the description gives a post-infusion window of 1 to 2 days. Without further information about event definitions, collection procedures, and overlap between event categories, readers cannot determine the full scope of what the count captures. The stated follow-up of approximately 44 weeks adds context but does not resolve those measurement questions.
Finally, the record distinguishes outcome intentions from analyzed results. It identifies steroid dosing and exacerbation rate as secondary outcomes, lists 5 outcome measures, and records 0 analyses. This makes clear why a registry entry should not be read as a complete statistical report: design details and outcome titles do not substitute for estimates, uncertainty measures, and transparent analysis methods. Planning illustrations likewise answer a prospective design question under assumptions; they are not findings from the trial. These distinctions are central to interpreting small clinical studies responsibly.
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 enrollment of 10 and the safety denominators of 10 place the results in a small-study context. Counts from a group of this size provide limited information about the range and frequency of possible events, and no confidence interval is reported to show statistical uncertainty. The registry record does not report baseline characteristics, so the clinical profile of the participants cannot be assessed from the recorded information.
The study is single-group, open-label, and has no listed comparator. This limits causal interpretation and makes it impossible to estimate a between-group treatment difference from the registry counts. The record does not report detailed treatment dosing, administration, background medication rules, steroid-taper procedures, or adherence. These omissions limit understanding of what treatment exposure the outcomes represent.
Safety reporting is also limited in detail. The record gives participant counts for serious and other adverse events and identifies Fractured Hip as the top serious term, but it does not report event-level timing, causality, severity beyond the serious classification, or whether the categories overlap. The primary endpoint describes side effects 1 to 2 days after infusion, while follow-up is approximately 44 weeks; how these descriptions relate to collection of all safety results is not reported.
For efficacy-related questions, the record names secondary outcomes but reports 0 analyses. Statistical methods, analysis populations, missing-data handling, multiplicity procedures, and interim analyses are not reported in the registry record. The absence of those details means that no conclusions about the outcomes' precision, completeness, or prespecification can be drawn from the recorded information.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Mepolizumab As a Steroid-sparing Treatment Option in the Churg Strauss Syndrome — NCT00527566.
- Registry record last updated 2017-03-22; status last verified 2017-02.
- Results first posted 2017-03-22.
- 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
NCT00527566 is a completed Phase 1 and Phase 2, open-label, single-group study sponsored by Brigham and Women's Hospital. The registry record lists Churg Strauss Syndrome, enrollment of 10, a start date of 2007-09, and primary completion on 2009-08. Participants received mepolizumab; no comparator is listed.
The primary endpoint is the number of participants with indicated side effects, described as effects experienced 1 to 2 days after infusion, with follow-up of approximately 44 weeks. The safety record reports one participant with a serious adverse event and nine with other adverse events, each among 10 at risk. Fractured Hip is the top serious adverse event term, reported as 10.0%.
The registry names secondary outcomes related to steroid dosing, overall positive change in CSS, and exacerbation rate. It lists 5 outcome measures and 0 analyses. Comparative efficacy results, inferential statistics, and details of missing-data and multiplicity methods are not reported in the registry record.