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 S9811 Hydroxyurea in Treating Patients With Unresectable Benign Meningioma (NCT00003590), a na phase 2 study. The primary outcome is Assess Number of Patients Who Achieve Confirmed and Unconfirmed Complete Response (CR) or Partial Response (PR).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00003590 |
| Phase | Phase 2 |
| Condition | Adult Meningioma |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 29 |
| Arms in the primary outcome | n/a |
| Lead sponsor | SWOG Cancer Research Network |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned patients with adult meningioma described as unresectable and benign. The response population was defined as all eligible patients who started treatment. The registry record does not report how many patients met that response-population definition. Total enrollment was 29.
Intervention
Participants received hydroxyurea, a drug intervention. The registry summary gives a general rationale involving chemotherapy drugs and tumor-cell division, but it does not report the treatment schedule or dose.
Comparator
There was no comparison group: the study is recorded as single-group, with allocation listed as not applicable. It was not masked. Consequently, the study was not designed as a randomized, like-for-like comparison between hydroxyurea and another treatment or control.
Primary question
The primary endpoint asked how many participants achieved a complete or partial response, whether confirmed or unconfirmed. The registry defines the response criteria and the confirmation requirement, but the primary response count or estimate is not reported in the registry record. The clinical question is therefore identifiable, while the magnitude of the reported response cannot be described from this record.
3. Trial Design
This was a phase II, single-group study of hydroxyurea for unresectable benign meningioma. The registry lists 29 participants enrolled. Allocation is recorded as not applicable, and masking as none; there is no concurrent control arm against which to compare outcomes. The sponsor is SWOG Cancer Research Network. The study began in 1998-11, reached primary completion in 2008-12, and is recorded as completed.
The primary outcome was the number of participants who achieved confirmed or unconfirmed complete response or partial response. The registry states that all eligible patients who started treatment were included in assessing response estimates. It does not report the count in that population. Treatment duration is described as up to 2 years or progression; participants responding could continue at the physician's discretion. This description does not establish the actual treatment duration for any participant.
A secondary outcome was the number of patients with grade 3 through 5 adverse events related to study drug. The record also gives safety counts for the hydroxyurea group. It lists no inferential analyses. The registry record does not report a randomized comparison, a prespecified comparator, or a statistical analysis plan. It also does not report details such as the hydroxyurea dose, visit schedule, or response-assessment schedule apart from the stated confirmation interval.
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.
Before assignment: All registered patients were to have eligibility assessed and sign informed consent prior to registration and receipt of protocol therapy.
Overall Study
| Stage | Hydroxyurea |
|---|---|
| STARTED | 29 |
| Eligible | 28 |
| Eligible and Began Protocol Therapy | 28 |
| COMPLETED | 7 |
| NOT COMPLETED | 22 |
Reasons for not completing this period:
| Reason | Hydroxyurea |
|---|---|
| Ineligible Patient | 1 |
| Adverse Event | 7 |
| Withdrawal by Subject | 1 |
| Lack of Efficacy | 11 |
| Death | 1 |
| Physician Decision | 1 |
Analysis population for the primary outcome, as defined in the registry: All eligible patients who started treatment were included in assessing response estimates.
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 | Hydroxyurea |
|---|---|---|
| Participants analysed | 28 | |
| Age, Continuous | years | 62 (24 to 84) |
| Sex: Female, Male: Female | Participants | 21 |
| Sex: Female, Male: Male | Participants | 7 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 27 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 |
| Race (NIH/OMB): White | Participants | 28 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 28 |
6. Primary Endpoint
The registry lists the primary outcome as Assess Number of Patients Who Achieve Confirmed and Unconfirmed Complete Response (CR) or Partial Response (PR), measured over Patients treated for 2 years or progression. If responding can continue at physician's discretion..
| Element | Registry entry |
|---|---|
| Result type | Number |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary endpoint counts participants who achieved complete response or partial response, including responses that were confirmed and those that were unconfirmed. A complete response is defined as disappearance of all measurable and evaluable disease, with no new lesions, no disease-related symptoms, and no evidence of non-evaluable disease. A partial response requires a decrease of at least 50% from baseline in the sum of products of perpendicular diameters for all measurable lesions, without progression of evaluable disease or new lesions.
Confirmation means that a repeat scan, at least 3 weeks apart, documented the response before progression. The registry defines no response as failure to achieve a complete or partial response, confirmed or unconfirmed. These criteria turn observations of tumor measurements and disease status into a defined response outcome. In general, a response endpoint can describe whether a prespecified change was observed during treatment; it does not, by itself, compare outcomes with what would have happened without treatment.
The registry identifies response as the primary outcome but does not report the number of participants who achieved either response category. It also does not report an uncertainty interval or other estimate of precision for the primary endpoint. Therefore, the outcome definition is available, but the result and its precision are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record describes a phase II study in which participants received hydroxyurea without a control group. Its central question was whether eligible participants who started treatment achieved complete or partial response under the stated criteria. The definition distinguishes complete response from partial response and requires a repeat scan at least 3 weeks apart for confirmation. These definitions clarify what counted as response; they do not supply the response result.
The primary outcome result is not reported in the registry record. No response count, response proportion, confidence interval, or inferential test is listed. The enrollment of 29 is not itself a response result and does not identify how many participants were eligible, started treatment, or were assessable for response. The registry does state that all eligible patients who started treatment were included in assessing response estimates, but the size of that population is not reported.
Because the design is single-group and has no randomized comparator, an observed response count, if available elsewhere, would describe outcomes among the treated study population. Such a count alone would not isolate the effect of hydroxyurea from other explanations, including the natural course of disease, participant selection, or other aspects of care. No causal comparison can be made from the design as recorded.
The safety information is also limited to counts. For hydroxyurea, the serious-adverse-event figures list 0 affected among 28 at risk, while the other-adverse-event figures list 28 affected among 28 at risk. These categories should not be conflated. The record separately identifies a secondary outcome concerning grade 3 through 5 adverse events related to study drug, but its result is not reported. Deaths are not reported in the safety figures.
There are no inferential analyses listed, and the registry record does not report confidence intervals, hypothesis tests, adjustment methods, or a statistical analysis plan. As a result, the precision and statistical uncertainty of the primary response outcome cannot be assessed from this record. The available information supports a description of the study's design, endpoint definitions, and recorded safety counts, but not a conclusion about the size or certainty of a treatment effect.
9. Statistical Methods Explained
The study is recorded as single-group, with allocation not applicable and no masking. In general, a single-group study observes outcomes in participants receiving the intervention without a concurrent comparison group. It can document what happened in the enrolled study population, but it does not provide a randomized estimate of the difference between hydroxyurea and an alternative. Without a control arm, changes or responses cannot be attributed to the intervention with the same comparative protection against bias that random allocation is intended to provide.
The primary measure is a participant count for complete or partial response, including confirmed and unconfirmed responses. This is a binary outcome at the participant level: each assessed participant is classified as having or not having a response under the defined criteria. The endpoint description specifies the required measurement changes and disease conditions. For confirmation, the registry requires a repeat scan at least 3 weeks apart, documented before progression. A confirmed response and an unconfirmed response are both included in the primary endpoint title, so they are not presented as separate primary outcomes in the available description.
In general, a count can be reported alone or used to estimate a proportion among a defined response population. The denominator matters: it identifies which participants contribute to that estimate. The registry says that response estimates included all eligible patients who started treatment, but does not report the number in that group or the primary response count. Enrollment of 29 therefore cannot be substituted for the response denominator. The record also does not report how participants with missing or unevaluable response assessments were handled.
A confidence interval is a statistical range intended to convey uncertainty around an estimate. Its width depends on the amount of information and the variability of the outcome, as well as the method used to construct it. No confidence interval for response is reported in the registry record. Without the response estimate, denominator, and interval, readers cannot judge the precision of the primary result from this record. No p-value or inferential analysis is listed either.
Multiplicity refers, in general, to the added risk of chance-positive findings when multiple outcomes or statistical tests are evaluated. A statistical plan can specify which outcomes are primary, how secondary outcomes are handled, and whether any adjustment is made when several tests are conducted. This record names a primary response outcome and a secondary adverse-event outcome, but does not report an analysis plan, testing hierarchy, or multiplicity adjustment. It also lists no analyses. It is therefore not possible to determine from the registry record whether multiplicity was addressed in any analysis outside the record.
Missing data can affect interpretation when participants do not have an evaluable outcome or withdraw before assessment. General methods include defining an analysis population in advance and explaining how missing observations are treated. The registry identifies the response population as eligible patients who started treatment, but does not give the population count, missing-data rules, or the number of unavailable assessments. The endpoint definition's use of no response for failure to achieve a complete or partial response does not, on its own, explain how genuinely missing response information was classified.
In general, over-dispersion describes variability greater than a chosen statistical model expects; it matters when count data are modeled using assumptions that allow less variability than the data exhibit. No count-model analysis, dispersion estimate, or model-based inference is reported for this study. The primary endpoint is described as a number of participants, and the registry lists no analyses. It would therefore be inappropriate to infer that an over-dispersion adjustment was used or needed.
The planning illustration associated with an observed effect is not the trial's original design justification and is not observed power. The registry record does not report a sample-size justification or a planned power calculation. It also does not report interim analyses or stopping rules. Those design and analysis details should be treated as not reported in the registry record rather than inferred from the study's phase or enrollment.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies a primary response outcome and a secondary outcome counting patients with grade 3 through 5 adverse events related to study drug. It does not report a statistical analysis plan, the number of planned statistical tests, a testing hierarchy, or any adjustment for multiplicity. No inferential analyses are listed. Consequently, the handling of multiple outcomes or possible repeated analyses is not reported in the registry record.
Missing-data handling is also not reported. The primary outcome population is described as all eligible patients who started treatment, but the size of that population, the number with unavailable assessments, and rules for incomplete or unevaluable data are not given. The registry's definition of no response does not specify how missing observations were classified. The record therefore does not establish whether missingness was absent, excluded, or handled through a particular method.
The record does not provide an analysis population count beyond the population definition, nor does it state whether any additional populations were analyzed. It does not report sensitivity analyses or methods for assessing the effect of missing outcomes. These omissions limit evaluation of how robust a response estimate would be to eligibility decisions, treatment initiation, or incomplete follow-up. They should not be filled in by assuming standard practice.
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 |
|---|---|---|---|
| Hydroxyurea | 0 | 28 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0.05% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Hydroxyurea | 28 of 28 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Hydroxyurea |
|---|---|---|
| Neutropenia/granulocytopenia | Investigations | 21 of 28 |
| Leukopenia | Investigations | 19 of 28 |
| Fatigue/malaise/lethargy | General disorders | 15 of 28 |
| Thrombocytopenia | Investigations | 14 of 28 |
| Headache | Nervous system disorders | 14 of 28 |
| Nausea | Gastrointestinal disorders | 12 of 28 |
| Lymphopenia | Investigations | 10 of 28 |
| Edema | General disorders | 8 of 28 |
| Dizziness/light headedness | Nervous system disorders | 7 of 28 |
| Diarrhea without colostomy | Gastrointestinal disorders | 6 of 28 |
The hydroxyurea safety figures list 28 participants at risk for serious adverse events, with 0 affected. For other adverse events, 28 were listed at risk and 28 affected. These are separate categories in the registry and should not be combined or interpreted as interchangeable measures. The figures describe the recorded counts; they do not, on their own, explain event severity within the other category, timing, duration, or participant-level overlap between categories.
The secondary outcome is described as the number of patients with grade 3 through 5 adverse events related to study drug. A result for that specifically defined outcome is not reported in the registry record. The safety figures do not provide a breakdown by event term, and the list of top serious-event terms is empty. Deaths are not reported. A count of affected participants is not the same as a count of individual events, since one participant can experience more than one event; the record does not provide event totals for these categories.
These counts should be read as descriptive safety information for the hydroxyurea group, not as a comparative risk estimate. With no control group, the registry does not support a comparison of adverse-event frequency against another treatment or untreated group.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a phase II, single-group study evaluated hydroxyurea in patients with unresectable benign meningioma. It specifies the primary response criteria, the intended response population, and a treatment period described as up to 2 years or progression, with continuation for responders at physician discretion. It also gives safety counts for the hydroxyurea group. These details help define the study question and how its outcomes were framed.
The record does not report the primary response count or estimate. It therefore cannot show how many participants achieved complete or partial response, nor how precise any response estimate was. Enrollment of 29 should not be treated as the number who responded or as a substitute for the defined response population. The registry also does not report a confidence interval, p-value, or inferential analysis for response.
Even if a response count were available, the single-group design would describe outcomes among treated participants rather than establish a comparative treatment effect. Without a control group, the record cannot separate treatment effects from other potential explanations for observed outcomes. It also does not report a statistical plan, missing-data rules, or a sample-size justification, so these aspects of the analysis cannot be evaluated.
The safety counts indicate 0 affected among 28 at risk in the serious-adverse-event category and 28 affected among 28 at risk in the other-adverse-event category. The specifically named secondary outcome concerning grade 3 through 5 events related to study drug has no reported result. These data should not be used to infer a comparison with another treatment or to fill in unreported details about event type, attribution, or deaths.
In short, the registry record defines a clinical question and reports selected design and safety information, but it does not report the primary efficacy result. It can support an account of what the study set out to assess, not a conclusion about the magnitude, precision, or comparative effect of hydroxyurea.
13. Why This Trial Matters Statistically
This study illustrates why endpoint definitions and analysis populations matter when reading a clinical trial. The registry specifies a response outcome with distinct criteria for complete and partial response, and it defines confirmation through a repeat scan at least 3 weeks apart. It also names the population intended for response estimates: eligible patients who started treatment. Those details are necessary for understanding what a reported response count would represent.
The record also shows the interpretive limits of a single-group design. Without a concurrent comparator, outcomes describe participants receiving hydroxyurea but do not provide a randomized contrast. That distinction remains important even when the endpoint is clearly defined and the study is completed. A study's phase and enrollment do not replace an estimate of the primary outcome or a measure of its uncertainty.
Finally, the registry record illustrates how incomplete reporting constrains statistical interpretation. It identifies the primary and secondary outcomes, yet does not report the primary response result, inferential analyses, missing-data procedures, or a multiplicity plan. For researchers and clinicians evaluating trial records, distinguishing a specified endpoint from a reported result is essential. The design, outcome definitions, and safety counts can be described; unreported estimates and methods cannot be reconstructed from those details.
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 for interpretation is that the primary response result is not reported in the registry record. The record defines complete and partial response, but gives no response count, estimate, or measure of precision. It also does not report the size of the eligible, treatment-started response population. Total enrollment is 29, but that figure does not establish the primary endpoint denominator.
The single-group design has no randomized comparator, so it cannot provide a direct comparative estimate against another treatment or control. Masking is listed as none. The record does not report the hydroxyurea dose, detailed treatment schedule, or full assessment schedule. Although the timeframe describes treatment for 2 years or until progression and physician-discretion continuation for responders, it does not show actual exposure or follow-up for individual participants.
Statistical details needed to assess analysis choices are not reported: the sample-size justification, analysis plan, interim analyses, missing-data rules, multiplicity approach, and inferential results. The secondary outcome concerning grade 3 through 5 adverse events related to study drug has no reported result. The safety figures do not include a detailed event-term breakdown, and deaths are not reported. These limitations prevent assessment of the primary result's precision and of several aspects of efficacy and safety reporting.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: S9811 Hydroxyurea in Treating Patients With Unresectable Benign Meningioma — NCT00003590.
- Registry record last updated 2016-05-20; status last verified 2016-04.
- Results first posted 2012-02-16.
- 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.
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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
NCT00003590 is a completed phase II, single-group study of hydroxyurea for unresectable benign meningioma, sponsored by SWOG Cancer Research Network. The registry lists 29 enrolled participants, no masking, and no randomized comparator. The primary outcome was the number achieving confirmed or unconfirmed complete or partial response among eligible patients who started treatment. The response criteria are defined, but the primary response result is not reported in the registry record.
The serious-adverse-event figures list 0 affected among 28 at risk; other adverse-event figures list 28 affected among 28 at risk. The specified secondary outcome for grade 3 through 5 adverse events related to study drug has no reported result. No inferential analyses are listed. The record does not report the sample-size justification, missing-data procedures, multiplicity handling, or statistical analysis plan.